How can I tell a catheter position from its electrograms?

Use the relationship between local atrial, His and ventricular signals, then confirm with imaging and pacing behavior. A His catheter can show a sharp His potential between atrial and ventricular electrograms. A coronary sinus catheter usually records a sequence of left atrial signals across its electrodes. Signal order changes with rhythm and activation direction, so a familiar trace alone does not establish position.

What does a pacing maneuver add to a tachycardia diagnosis?

It tests how the rhythm responds to a timed input. The pacing site, evidence of capture, sequence of subsequent electrograms and change in tachycardia timing all matter. For example, a ventricular premature beat delivered when the His bundle is refractory that advances the next atrial signal supports an accessory connection. An apparent response without confirmed ventricular capture or reliable His timing cannot carry the same conclusion.

Which findings should prompt urgent communication during an EP procedure?

A sudden fall in blood pressure, new loss of capture, sustained dangerous rhythm, abrupt change in conduction, unexpected bleeding or a new neurologic finding requires immediate attention. Check that the measurement or signal is real while alerting the team. The pattern and timing guide the next assessment: hypotension after transseptal or ablation work, for example, raises concern for pericardial effusion and warrants prompt imaging and coordinated response.

RCES Cardiac Electrophysiology Study Guide

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An RCES must connect the patient's condition, the recorded signals and the equipment in use. A rhythm strip alone may suggest an arrhythmia, but catheter electrograms, pacing responses and the clinical timeline often determine what is actually happening. This guide follows an EP procedure from preparation through handoff. You will work through catheter position, conduction intervals, pacing maneuvers, mapping, ablation and cardiac implantable electronic devices while keeping patient monitoring and equipment safety in view. The examples use stated measurements so that you can calculate and interpret them without treating an illustrative value as a universal clinical threshold. Throughout, the focus is the specialist's work: acquire reliable data, recognize changes, communicate findings promptly and support the responsible clinician's decisions.

Conducting Pre-Procedural Activities

1. Match the room to the planned procedure

Start with the ordered procedure and work backward through what each phase requires. A left atrial ablation needs surface ECG and intracardiac recording channels, a stimulator that delivers timed impulses, a mapping system with its reference patches, imaging, ablation connections, vascular supplies and a sterile field. Check that components communicate and that displayed signals have the expected channel labels before the patient depends on them. Confirm that resuscitation equipment is accessible, and arrange radiation shielding for people who will remain near fluoroscopy. The CCI RCES credential page includes room preparation among the role's tasks. A console that powers on is only one part of readiness: missing reference patches can prevent reliable catheter localization even when the recording system works. Match each check to the planned procedure and resolve gaps before that phase begins.

Worked example: A left atrial ablation is scheduled. The recording system displays test signals and the stimulator passes its output check, but no mapping reference patches are available. Those passing checks do not establish mapping readiness. Obtain the correct patches, apply them as required, and verify localization before collecting map points. Keep the gap visible to the team until it is resolved.

Watch the distinction: A common error is treating a successful equipment self-check as proof the whole room is ready. Mapping, imaging, sterile supplies and rescue equipment each need their own procedure-specific check.

Reference: [1]

2. Reconcile the record and procedure plan

The schedule, procedure order and signed consent serve different purposes. Read them together with the history, allergies, relevant laboratory results and device information before setup is finalized. A mismatch may change which catheters, energy equipment, medication monitoring or rescue supplies the team needs. During the time-out, the team confirms the patient, intended procedure and other required details against the authoritative record rather than silently choosing whichever label seems most likely. The RCES contributes by identifying discrepancies, documenting or conveying the relevant facts and holding preparation at a safe point while the responsible team reconciles them. A consent that mentions ablation does not by itself prove ablation will occur, just as a schedule entry cannot narrow a signed order. The operative plan must be made clear before equipment use depends on it.

Worked example: The schedule reads “diagnostic EP study,” while both the signed consent and physician order include possible ablation. Before opening ablation instruments, tell the operator and circulating team about the mismatch. Have the team reconcile the schedule with the intended procedure during verification. Prepare according to the confirmed plan, including equipment and monitoring needed if ablation proceeds.

Watch the distinction: Do not assume the schedule is the final authorization because it is visible on the room board. It can lag behind an updated order or consent and must be reconciled.

Reference: [1]

3. Verify identity through transport

Identity checking is a continuous handoff task, including the move from a holding area to the EP room. Compare two independent patient identifiers on the wristband with the record and transport documentation; a room number or procedure label is not a reliable identifier. Then confirm the intended destination and procedure with the receiving team. Transport also carries clinical information: current rhythm, oxygen or monitoring needs, IV access, mobility limits and any change since the last assessment. Keep required monitoring connected or provide an agreed equivalent during the move. If an identifier conflicts, stop at a safe point and resolve it through the care team before transfer proceeds. A familiar name, matching face or correct procedure does not compensate for a conflicting identifier because records for two patients can otherwise be combined.

Worked example: A transport request and wristband show the same name, but their dates of birth differ. Keep the patient in the monitored care area and compare the wristband, record and request with the responsible staff. Once the erroneous entry is corrected and two independent identifiers agree, give the receiving team the rhythm and monitoring handoff, then continue transport.

Watch the distinction: Matching names alone can feel sufficient, especially when the patient recognizes the procedure. Names can repeat, and a wrong date of birth may reveal a record or request mismatch.

Reference: [1]

4. Prepare monitoring and implanted devices

Before an EP procedure, check that IV access is usable, the patient can tolerate the planned position, monitoring electrodes have good skin contact and external rescue pads are correctly placed when needed. For a patient with a cardiac implantable electronic device, identify the device type and its relevant programmed behavior, alerts and baseline rhythm from interrogation. Electrosurgery and ablation can produce signals the device may sense as cardiac activity; the team's plan may therefore address therapy settings, pacing dependence and how function will be checked afterward. Record the initial state so later changes can be interpreted. A paced QRS on the monitor establishes that a paced beat occurred, not that sensing, battery status, stored events or all lead functions are satisfactory. The RCES prepares equipment, communicates findings and supports the clinician-directed device plan.

Worked example: A patient with an ICD is scheduled for ablation that may involve electrosurgery. Document the initial rhythm, device settings, lead information and active alerts. Confirm the team's plan for device therapy and postprocedure checks. Ensure ECG and hemodynamic monitoring and external rescue equipment are ready before energy delivery; a visible paced beat alone cannot verify ICD readiness.

Watch the distinction: A tempting shortcut is to regard a normal-looking paced rhythm as a complete device check. Interrogation can reveal alerts or stored events that the current surface strip cannot show.

Reference: [1]

5. Prepare the site without breaking sterility

An insertion site must permit the planned catheter route while giving the operator a clean, usable working area. Prepare the skin and place drapes so the access region remains visible and sterile instruments can reach it without crossing unprepared surfaces. Sterility is a chain of contact: a prepared patch of skin cannot protect a sheath if a contaminated cable touches the sterile field or hardware. Notice where imaging cables, recording leads, ultrasound equipment and staff hands will pass before access begins. If a breach occurs, identify what was touched, remove affected sterile items and restore the field. The RCES should communicate the breach plainly rather than trying to hide it beneath a new drape. The same reasoning matters at vascular access and at a device pocket, where contaminated hardware may be implanted.

Worked example: After femoral preparation and draping, a nonsterile recording cable crosses the intended access field and contacts a sterile drape. Stop setup at that point and tell the sterile team. Remove the cable from the field, replace the affected drape and any contacted sterile items, then re-establish a clean path for cables before vascular access begins.

Watch the distinction: Covering a contaminated area with another drape does not restore sterility to an item already touched. Trace the contact and replace affected material before proceeding.

Reference: [1]

Conducting Intra-Procedural Activities

6. Track comfort alongside sedation

Patient comfort and signal quality are linked in EP work: movement can change catheter contact, distort electrograms and invalidate map points. Yet a restless patient may be uncomfortable, hypoxemic or developing a sedation-related ventilation problem. Track respiratory effort, oxygenation, pressure and rhythm alongside the timing of medication and procedural stimulation. Pulse oximetry can lag behind a fall in ventilation, so shallow breathing deserves attention before a severe displayed change appears. Tell the clinician or sedation professional responsible for airway and medication management what changed, and pause measurements that depend on stable contact while assessment occurs. The RCES can support positioning, monitoring and equipment readiness within the team plan. Sedation should never be increased merely to quiet noisy recordings without first evaluating why the patient is moving.

Worked example: During activation mapping, a patient becomes restless after sedation. Breaths become shallow, oxygen saturation falls from the previously stable trend and catheter electrograms vary with movement. Alert the sedation team, report the respiratory and signal changes together, and pause point collection. Resume only after the patient's ventilation and recording conditions have been assessed and stabilized.

Watch the distinction: Calling movement a mapping nuisance can delay recognition of impaired ventilation. The correct first question is what changed in the patient, followed by whether the resulting electrograms remain usable.

Reference: [1]

7. Interpret a change in vital signs

A vital-sign value has meaning in its timeline. When pressure falls, first check the tracing, transducer or cuff and whether the change repeats; at the same time, look at rhythm, oxygenation and the procedural step that just occurred. An unchanged heart rate does not rule out blood loss, tamponade or another hemodynamic problem. After transseptal access, sustained hypotension deserves prompt communication because an effusion can impair filling before a distinctive rhythm change appears. The RCES reports the magnitude and trend, confirms the measurement and helps make imaging and rescue equipment available while the responsible team evaluates the cause. Avoid spending minutes troubleshooting a monitor when the patient also shows signs of poor perfusion. Conversely, one isolated artifact should not be treated as a diagnosis without checking the patient and an independent measurement.

Worked example: Immediately after septal crossing, invasive pressure falls from its stable baseline on several beats, while the ECG rate remains similar. Check the transducer connection and compare an independent pressure or clinical perfusion sign. Promptly report persistent hypotension and the timing of access. Support the team's assessment for bleeding or pericardial fluid rather than attributing it to the stable rate.

Watch the distinction: A steady heart rate can falsely reassure the team. Pressure reflects filling and vascular resistance as well as rhythm, so a sustained drop still needs urgent evaluation.

Reference: [1]

8. Recognize medication effects on EP findings

EP measurements can change because a drug alters conduction, because pacing conditions change or because a complication develops. Use administration time and the drug's expected site of action as clues, then compare intervals recorded under similar conditions. The AH interval runs from the atrial electrogram to the His potential and reflects conduction through the AV nodal region; HV runs from His to ventricular activation and reflects downstream conduction. An AV nodal blocking drug can lengthen AH while HV remains stable. That pattern localizes the measured delay but does not prove every concurrent change is benign. Continue watching rate, pressure and rhythm, and report excessive slowing or a new unstable finding. The RCES documents the measured effect and chronology, while medication decisions remain with the responsible clinician.

Worked example: Before a clinician-administered AV nodal blocking medication, AH is 90 ms and HV is 45 ms. Under comparable pacing conditions afterward, AH is 140 ms and HV remains 45 ms. AH lengthened by 50 ms, while the measured His-to-ventricle interval changed by 0 ms. Report an AV nodal-region effect with the drug timing, and continue monitoring pressure and conduction.

Watch the distinction: Do not label every longer atrial-to-ventricular interval as His-Purkinje disease. Separate AH from HV and compare the same pacing conditions before localizing the change.

Reference: [1]

9. Support vascular access safely

Access planning begins with the intended chamber and catheter route, then determines which vessel, sheath and imaging support are needed. For venous EP access, ultrasound can help distinguish vein from artery and show needle position; the observed pressure waveform and blood characteristics may provide additional clues. No single visual cue is infallible. Bright pulsatile return during a planned venous puncture raises concern for arterial entry, and advancing a dilator can turn a small puncture into a larger injury. Communicate the finding before sheath advancement and support the operator's reassessment with imaging or pressure information. Once access is established, watch for bleeding, hematoma and changes in distal perfusion. The related RCIS study guide covers broader invasive cardiovascular access, while EP preparation also depends on the planned intracardiac catheter route.

Worked example: The team plans a femoral venous sheath for a diagnostic EP catheter. At needle puncture, the return is bright and pulsatile. Tell the operator immediately and do not prepare to advance the dilator as though venous access is confirmed. Support vessel identification with the available imaging and pressure assessment, then proceed only after the team establishes the correct route.

Watch the distinction: Blood color alone cannot prove vessel identity because oxygenation and lighting vary. A concerning return requires confirmation before dilation, where an access error becomes harder to reverse.

Reference: [1]

10. Trend anticoagulation measurements

Activated clotting time is a point-in-time measure of anticoagulation effect, so its interpretation depends on when blood was drawn relative to medication, procedures and prior samples. Plot values in chronological order and label the actual draw time, administration time and result time separately. A sample collected before an anticoagulant dose cannot show that dose's effect, even if the result arrives afterward. Compare serial values with the team's target for that procedure and with the sampling method used; do not infer a universal target from a single number. Unexpected results also warrant checking specimen identity, timing and collection issues before they drive a decision. The RCES communicates the trend and any chronology error, then obtains a requested repeat sample. This protects decisions during left-sided instrumentation without assigning medication doses to the technologist.

Worked example: An ACT sample is drawn at 09:12, an anticoagulant is given at 09:16 and the 09:12 result appears at 09:20 labeled “postdose.” The label is chronologically wrong by four minutes. Correct the record, tell the team the value reflects predose blood, and obtain the requested later sample to assess the medication effect against the procedure-specific target.

Watch the distinction: Result time is not sample time. Treating a predose specimen as postdose may make anticoagulation appear inadequate and distort the team's next decision.

Reference: [1]

11. Connect glucose and blood gas results to monitoring

Glucose and blood gas results add physiologic context to continuous EP monitoring. Glucose extremes can alter patient status and complicate a long procedure; acid-base and gas changes may affect myocardial excitability and hemodynamics. A rising carbon dioxide level with shallow ventilation suggests reduced alveolar ventilation, particularly when recorded after sedation. New ectopy at the same time deserves attention, but temporal association alone does not prove carbon dioxide caused it. Compare the gas result with respiratory rate, capnography if available, oxygenation, pressure and rhythm strips. State specimen type and collection time when reporting a gas because arterial and venous values answer different questions. The RCES relays the combined trend to the responsible team and continues recording rhythm changes while the team assesses ventilation and other causes.

Worked example: During a prolonged sedated procedure, an arterial blood gas shows carbon dioxide rising from 42 to 55 mmHg while observed breathing slows and ventricular ectopy becomes more frequent. Report the 13 mmHg increase, sample timing, ventilation change and ectopy together. The team can assess ventilation and competing causes; the gas result alone does not diagnose the rhythm mechanism.

Watch the distinction: It is easy to treat a blood gas and ectopy strip as unrelated displays. Their timing may identify a shared physiologic change, though it cannot establish causation by itself.

Reference: [1]

12. Read the device interrogation summary

Interrogation gives a device history that a surface ECG cannot provide. Identify the device type and programmed mode first, then review battery status, lead measurements, alerts and stored episodes with their timestamps. A pacing percentage describes how often the device recorded pacing over its reporting period; it does not show whether every paced beat captured or why high-rate events occurred. Stored electrograms, when available, help distinguish a recorded rhythm from oversensing or artifact, but the episode still needs clinical context. Compare findings with the current rhythm and the planned procedure, especially when electromagnetic interference or programming changes are expected. The RCES should convey specific alerts and relevant episode timing to the operator, preserving baseline data for later comparison. A single visible spike is a narrow observation, not a summary of device function.

Worked example: A patient shows intermittent ventricular pacing on the monitor. Interrogation also reports a lead alert and two stored high-rate episodes from the previous day. Record the programmed mode, battery and lead data, then relay the alert and episode times with the current rhythm. The present pacing pattern does not explain the alert or establish that the prior episodes were clinical tachycardia.

Watch the distinction: Reporting only the paced percentage can bury the actionable finding. An alert or stored electrogram may change how the team interprets a seemingly ordinary surface rhythm.

Reference: [1]

13. Separate capture, sensing and lead integrity

Capture, sensing and impedance test different parts of a pacing system. Capture asks whether an output pulse depolarizes myocardium at a given voltage or current and pulse width. Sensing asks whether the device detects intrinsic cardiac signals of sufficient amplitude. Lead impedance reflects resistance along the electrical path and can shift with conductor, insulation or connection problems. Interpret these measurements together and against prior values rather than as independent pass marks. An abrupt impedance rise with intermittent loss of capture suggests a possible interruption in the output path, although confirmation requires more than one observation. A visible intrinsic electrogram only shows that some signal reaches the sensing circuit; it cannot prove every output pulse reaches tissue. The RCES documents test conditions, checks connectors and lead data as appropriate, and reports the pattern for clinical troubleshooting.

Worked example: A ventricular lead previously measured 520 ohms; it now measures 1,450 ohms on the same interrogation, and some paced outputs lack a following ventricular response. Intrinsic ventricular signals remain visible. The impedance increased by 930 ohms, alongside intermittent capture failure. Report the abrupt change and check the connection and lead information; preserved sensing does not clear the output pathway.

Watch the distinction: Seeing sensed intrinsic beats can tempt you to call the lead normal. Sensing and delivery use related hardware but test different functions, so capture failure still needs investigation.

Reference: [1]

14. Decode a pacing mode

The first three positions of an NBG pacing code state the paced chamber, sensed chamber and response to a sensed event. In VVI, the device paces the ventricle, senses the ventricle and inhibits a scheduled output when it detects a qualifying native ventricular beat. The timing cycle resets or adjusts according to the device's programmed behavior, so a missing spike after a native QRS may be exactly what the mode intends. Confirm that the sensed beat occurred inside the relevant timing window and that the device detected a true cardiac signal. Oversensing of noise can also inhibit output and may be dangerous in a pacing-dependent patient. Read the ECG together with device markers and interrogation data before deciding whether inhibition is appropriate. The code describes intended logic; actual capture and sensing still require observation.

Worked example: A VVI device is set to a hypothetical lower rate of 60 beats per minute, equivalent to a 1,000 ms interval. A native ventricular beat occurs 700 ms after the last paced beat, and the next scheduled spike is absent. If markers confirm native sensing, inhibition explains the gap. Check subsequent timing and capture before calling the behavior normal overall.

Watch the distinction: A missing spike is not automatically a pacing failure. In an inhibiting mode it may be expected, but noise oversensing can produce a similar surface appearance.

Reference: [1]

15. Match equipment to procedure phase

EP equipment changes purpose across procedure phases. Diagnostic catheters must deliver interpretable intracardiac signals through the right connectors and recording channels; mapping catheters also need a recognized geometry and localization reference; ablation catheters require compatible energy and safety connections. Physical fit does not establish electrical, software or dimensional compatibility. Before collecting points, verify the catheter model selected in the 3D system, electrode order, connection path and reference stability. A wrong geometry can place apparently precise points at false positions, making later activation or lesion decisions unreliable. During implantation, analogous checks link leads, analyzer cables and programmer settings to the device being tested. The RCES should recognize which data each setup can validly produce and stop using a display when its configuration is uncertain.

Worked example: A mapping catheter plugs into its interface and displays electrograms, but its model is absent from the 3D system's selected-device list. Signal recording may still work; localization cannot yet be trusted. Verify the catheter and interface model, update the system selection or obtain compatible equipment, then validate geometry before acquiring map points. Do not retain points collected under an unverified configuration.

Watch the distinction: A matching plug can give false confidence. Hardware may connect while the mapping software applies the wrong electrode spacing or has no valid geometry for the catheter.

Reference: [1]

16. Respond to a sterile-field breach

A sterile field depends on the contact history of each item, not on whether it still looks clean. Gloves, drapes, instruments and implant components lose sterile status when they touch an unprepared surface or pass through an unprotected path. At a device implant, a lead connector is part of hardware that may enter or remain near the pocket, so a breach has direct significance. Identify the affected component and any secondary contacts, tell the sterile team, and replace or reprocess items as appropriate before proceeding. Avoid moving a contaminated item across the field while resolving the problem. The RCES can protect workflow by anticipating cable routes and by keeping sterile and nonsterile personnel roles clear. A delay to restore the field is preferable to concealing a breach that later cannot be traced.

Worked example: During implantation, a sterile lead connector slips onto an undraped table. It still appears clean, but the table is outside the sterile field. Tell the operator and remove the connector from use. Replace the affected component and any sterile item it subsequently touched, then re-establish a protected route to the pocket before testing or connection continues.

Watch the distinction: Wiping a breached implant component at the bedside does not automatically restore sterility. The contact history determines whether it can be used, regardless of visible soil.

Reference: [1]

17. Set up a trustworthy EP recording

An EP interval is a measurement between specified electrogram deflections on a known time scale. Verify channel labels first: mistaking a ventricular channel for a His channel changes the physiological meaning of a cursor pair. Set gain so small signals are visible without clipping, choose a sweep speed that separates nearby deflections and retain timing markers. Increasing sweep speed spreads events farther apart on the screen but does not lengthen conduction in the patient. Measure from consistent onset or peak conventions under comparable rhythm and pacing conditions. If a displayed AH interval changes after a settings adjustment, revisit the original trace and cursor placement before reporting a biological change. The RCES protects diagnostic value by preserving raw recordings and noting display adjustments, since later review may need to distinguish acquisition changes from physiology.

Worked example: On a trace at 100 mm/s, an A-to-H separation spans 10 mm, giving 10 mm ÷ 100 mm/s = 0.10 s, or 100 ms. At 200 mm/s, the same interval spans 20 mm: 20 ÷ 200 = 0.10 s. If the displayed value differs, check cursors and channel labels before concluding AH changed.

Watch the distinction: More screen distance between deflections after a sweep-speed increase is a display effect. Convert distance using the current scale before interpreting conduction.

Reference: [1]

18. Operate the stimulator with capture checks

The stimulator specifies when and how strongly impulses are delivered; the myocardium determines whether they capture. Cycle length is the interval between programmed stimuli, so stimulus frequency in impulses per minute equals 60,000 ms per minute divided by cycle length in milliseconds. That calculation describes the stimulator train only. Verify a local evoked electrogram or consistent surface response after each stimulus to establish capture, and watch for artifact that can mimic a response. Output, pulse width, catheter contact and tissue properties all affect capture. If beats are missed, identify whether stimuli failed to fire, failed to reach the catheter or reached tissue without depolarization. Document the setting and observed capture separately. The RCES practice questions can reinforce this distinction between programmed timing and actual cardiac response.

Worked example: A drive train has a 600 ms cycle length. Its programmed rate is 60,000 ms/min ÷ 600 ms/stimulus = 100 stimuli/min. If every alternate stimulus fails to capture and the pattern is regular, effective captured responses occur about every 1,200 ms, or 50 beats/min from pacing. Check output and catheter contact before interpreting conduction at the intended train rate.

Watch the distinction: Do not report programmed stimuli per minute as the patient's paced heart rate when capture is intermittent. The ECG and intracardiac response determine effective pacing.

Reference: [1]

19. Trace noise through the signal chain

Noise can enter at the electrode, catheter contact, cable, connector, amplifier or display. Its distribution helps locate the fault. Artifact confined to one bipolar pair points toward that pair's electrodes or its connection; simultaneous artifact across many channels suggests a shared cable, reference, amplifier or external source. Compare the noisy channel with adjacent intracardiac pairs and the surface ECG, then look for a physiologic activation sequence. A true arrhythmia generally changes organized atrial or ventricular activity across relevant channels, while electrical noise may be abrupt, high frequency and disconnected from hemodynamic or ECG changes. Inspect accessible connectors and cables without disturbing sterile boundaries, and preserve a strip of the event for review. The RCES should report uncertainty when a noisy signal could mask a real rhythm change rather than declaring the patient stable from one clean channel.

Worked example: One bipolar catheter pair develops rapid irregular spikes, while neighboring pairs, surface ECG and blood pressure remain unchanged. The pattern localizes suspicion to that pair's contacts or cable rather than a new global tachycardia. Save the strip, inspect the accessible connection and compare signals after correction. Continue patient monitoring because a local artifact can still hide useful electrograms.

Watch the distinction: A dramatic intracardiac trace can look like fibrillation. Before naming an arrhythmia, ask whether other channels and the patient's pulse show a corresponding change.

Reference: [1]

20. Know what filters can hide

Filters change the displayed frequency content of an electrogram. A high-pass setting can suppress slow baseline movement but also attenuate broad components; a low-pass setting can reduce high-frequency noise while blunting small, sharp potentials. Gain changes amplitude on the screen without restoring information already removed by filtering. Because the His potential may be small and brief between atrial and ventricular signals, inappropriate settings can make it disappear or shift the apparent point chosen for measurement. Compare channels and a saved trace made before the change, restore a suitable recording configuration and then place interval cursors. Do not infer that His-Purkinje conduction vanished simply because the H deflection is no longer visible. If the signal remains absent under appropriate settings, also consider catheter position and contact before interpreting the physiology.

Worked example: A clear A-H-V sequence is recorded, then a filter change leaves visible A and V components but no distinct H. Return to the earlier settings and compare the saved trace. If H reappears, the loss was a display or acquisition effect, and HV should be measured from the valid trace. If it does not, reassess catheter position and signal quality.

Watch the distinction: A missing displayed H after a filter change does not prove new conduction block. First determine whether the recording setup removed a small signal needed for HV measurement.

Reference: [1]

21. Build a stable 3D mapping reference

A 3D mapping system calculates catheter position relative to a reference, so the reference must remain stable while points are collected. Surface patches, intracardiac reference electrodes, catheter connections and the selected localization method all affect the displayed geometry. Check that patches adhere firmly and that the reference catheter has not moved before accepting a new location. Respiration can shift the heart within the chest; patient repositioning can shift the entire coordinate relationship. A sudden, similar displacement of many previously collected points suggests a reference change more strongly than simultaneous movement of every cardiac structure. Compare catheter location with electrograms and live imaging, then revalidate the reference and affected geometry before further mapping. The RCES task outline includes operation and troubleshooting of 3D mapping systems within the specialist’s work.

Worked example: During right atrial mapping, the patient is turned slightly and every saved point appears displaced by about 12 mm in the same direction. The local electrogram sequence and fluoroscopic catheter position look unchanged. A shared 12 mm shift points to a changed reference or coordinate registration. Tell the operator, check patches and reference position, and revalidate the map before adding points.

Watch the distinction: Treating the shifted display as new anatomy could send the catheter toward the wrong target. A geometry change needs confirmation against stable signals and independent imaging before it guides movement.

Reference: [1]

22. Judge whether a mapping point is valid

An activation map is only as reliable as the beats and electrograms used to build it. First confirm that the catheter is contacting the intended tissue and that its position is stable. Then inspect the local bipolar signal: a sharp near-field deflection that changes predictably across adjacent electrodes usually gives a better timing marker than a broad component seen everywhere. Use the same reference and comparable rhythm for each point. A premature beat, changing cycle length or loss of capture can alter activation order, making its timing unsuitable for a map of the clinical rhythm. Automated annotations also need visual review because the software may mark a pacing artifact, far-field signal or late component. If an apparently earliest point conflicts with contact, signal shape or neighboring points, exclude it or correct its annotation and collect more comparable beats.

Worked example: A point is labeled 32 ms before the surface QRS, earlier than its neighbors. Its deflection is broad on several electrodes, and it was collected during a premature ventricular beat. Nearby beats in the target rhythm show a sharp local signal 14 ms before QRS. Exclude the premature-beat point from this map, verify contact, and compare repeat points before naming an earliest site.

Watch the distinction: The most negative displayed time is not automatically the source. An incorrect annotation or a beat from another rhythm can create an early point with no valid local activation.

Reference: [1]

23. Reduce radiation exposure

Radiation reduction starts with using X-rays only when they answer a positioning or safety question that other available views cannot answer. Shorter fluoroscopy time reduces exposure; lower pulse or image acquisition rates can reduce it further when image quality remains adequate for the task. Staff can step back during imaging, because scatter generally falls with distance, and use properly positioned shields and personal protective equipment. Keep hands out of the primary beam and avoid unnecessary magnification or repeated image runs. A 3D map supplies catheter location within its registered geometry, while fluoroscopy can verify hardware course and relationships that require an X-ray view. Reassess which display is needed at each step. For a deeper comparison of projection and dose concepts, see the cardiac interventional radiography guide.

Worked example: A catheter is being moved between two already validated mapping sites. Its position and electrograms remain clear on the 3D display, while continuous fluoroscopy adds no needed detail. The team can navigate on the map and use brief fluoroscopic checks when hardware position requires confirmation. This reduces beam time while retaining imaging for the decision it can resolve.

Watch the distinction: Turning fluoroscopy off without checking what the team needs can obscure hardware or anatomy. Radiation reduction requires selecting the lowest exposure that still supplies the necessary information.

Reference: [1]

24. Use fluoroscopic views to resolve depth

Fluoroscopy compresses a three-dimensional catheter path onto a two-dimensional image. Two tips can appear superimposed even when one is anterior and the other posterior. Rotating to a sufficiently different projection changes which structures overlap and can reveal depth or chamber relationships. Use known landmarks, catheter shape, electrogram components and the planned route alongside the second view. A coronary sinus catheter, for example, can help orient the atrioventricular groove, but its projected course alone does not prove the precise location of another tip. When changing projection, account for the altered appearance of left and right on the monitor and identify the actual view before interpreting movement. If the two views still leave uncertainty, use available ultrasound or mapping information and communicate that uncertainty before the operator advances the catheter.

Worked example: A His recording catheter and a right ventricular catheter tip overlap in one projection. Their electrograms differ, but the image cannot show which tip lies deeper. A second, substantially rotated view separates the tips and shows the ventricular catheter farther along its expected course. Combine that view with the A-H-V and ventricular signals before assigning landmarks.

Watch the distinction: A single projected overlap does not mean two tips occupy the same site. Assigning a chamber from that view alone can mislabel electrograms and misdirect subsequent pacing.

Reference: [1]

25. Combine radiographic and nonradiographic images

Each imaging method answers a different question. Fluoroscopy shows radiopaque hardware and its projected motion in real time, but has limited soft-tissue detail. Intracardiac echo shows live septal, valve, wall and pericardial anatomy, though its interpretation depends on probe orientation and image quality. A 3D mapping system relates recorded points to a constructed chamber geometry; localization errors or an outdated reference can make its display disagree with the patient’s present anatomy. MRI-derived anatomy may add structural detail, but a preprocedure image is not live and registration can drift. When displays conflict, identify which observation directly addresses the next action. For catheter advancement toward tissue, current live anatomy and pressure or electrogram findings deserve immediate attention. Report the discrepancy, pause advancement and help the operator reconcile the images rather than treating one screen as universally authoritative.

Worked example: A map icon sits on the intended septal target, but intracardiac echo shows the tip tenting an adjacent structure. The map describes its registered position; echo shows the current tissue contact. Tell the operator about the conflict before further advancement. Recheck catheter identity, reference stability, echo orientation and other location evidence before the team proceeds.

Watch the distinction: Assuming a registered map always matches live tissue can conceal reference drift or imperfect image fusion. A plausible icon location does not overrule direct evidence of unintended contact.

Reference: [1]

26. Protect against electrical and fire hazards

Electrical injury and fire risk depend on the whole circuit, not just whether a generator powers on. Damaged insulation or loose connectors can permit unintended current paths, heating, interference or unreliable energy delivery. Inspect cables and connections before use and remove suspect equipment from service. During electrosurgery, the return electrode and cable path matter because poor contact can concentrate current at an unintended site. Energy delivery may also interfere with implanted devices, so monitoring and the team’s device plan must be ready. A fire requires an ignition source, fuel and an oxidizer; electrosurgery can supply ignition near drapes or other materials, especially where oxygen has accumulated. Keep the operative field arranged to limit that combination and communicate hazards before activation. The RCES role includes recognizing these risks and supporting the responsible team’s response.

Worked example: Before a device pocket is opened, a cable beside the drapes has cracked insulation. The electrosurgical console has passed its internal check, but that check has not tested the full cable surface. Stop setup with that cable, report the defect and replace it. Confirm the replacement connection and the planned oxygen and drape arrangement before energy use.

Watch the distinction: A normal console self-check cannot establish that every external lead is intact. Using a visibly damaged cable risks stray current or ignition despite a normal console display.

Reference: [1]

27. Recognize an intra-procedure emergency

During an EP procedure, a sudden pressure or rhythm change should trigger simultaneous verification and communication. Check whether the displayed abnormality is physiologic by comparing surface ECG, intracardiac electrograms, pulse or arterial tracing and the recent procedural event. Do not let verification delay an urgent alert when the patient is unstable. Complete atrioventricular block shows atrial activity without consistent conduction to ventricular activation; the ventricular rhythm may be slow or absent. If it appears during catheter manipulation and pressure falls, alert the operator and the team managing resuscitation, continue monitoring, and make ordered pacing and emergency equipment ready. Keep the chronology clear: what moved, what changed first and which signals confirm it. That sequence helps distinguish a transient recording fault from a clinically important complication, while treatment decisions remain with the responsible clinicians.

Worked example: Immediately after septal catheter movement, atrial electrograms continue at 80 per minute, but ventricular events fall to an independent 35 per minute and arterial pressure declines. The differing rates and lost A-to-V relationship support new complete AV block. Announce the finding, verify the pulse and tracing, and prepare temporary pacing support as directed while the team assesses the patient.

Watch the distinction: Waiting for several minutes to see whether the block resolves can prolong poor perfusion. A falling pressure with confirmed atrioventricular dissociation calls for immediate team communication and rescue readiness.

Reference: [1]

Performing Diagnostic Procedures

28. Identify diagnostic catheter locations

Diagnostic catheter identity comes from combining its route and image with its local electrical signature. A high right atrial catheter usually records a prominent atrial signal and can provide an atrial pacing site. A His-region catheter can record atrial, His and ventricular components in sequence, allowing AH and HV measurements when the deflections are clear. A right ventricular catheter has a dominant ventricular signal and provides ventricular pacing or recording. A catheter along the coronary sinus commonly displays a series of atrial electrograms across distal and proximal pairs, with ventricular components that vary by location. Activation sequence can change with the rhythm, so sequence alone does not establish the catheter’s position. Confirm the recorded signals against fluoroscopy or another available image, the expected course and pacing responses before labeling channels or using them to localize conduction.

Worked example: One catheter records distinct A, H and V deflections. A second has atrial signals appearing sequentially from distal to proximal pairs during the current rhythm. The first is positioned to record His activity; the second is consistent with a coronary sinus catheter. Check both against their imaged courses before assigning channel labels or interpreting the atrial activation direction.

Watch the distinction: Calling every sequential atrial recording a coronary sinus catheter ignores route and image evidence. A mislabeled catheter can reverse the apparent activation sequence and distort an arrhythmia interpretation.

Reference: [1]

29. Find a pacing capture threshold

A pacing capture threshold is the lowest tested output that produces reliable tissue capture under defined conditions. Hold pulse width constant, maintain catheter or lead contact, and reduce output in steps while checking each stimulus for a corresponding local electrogram and expected propagated response. A pacing spike by itself proves only that the stimulator delivered an output; it does not prove myocardial depolarization. Intermittent capture means the tested output is not consistently effective. Report the chamber, polarity if relevant, pulse width, output unit and stability of contact, because thresholds can change when these conditions change. Distinguish capture from conduction: an atrial stimulus may capture atrial tissue yet fail to conduct through the AV node. For a temporary catheter, reassess contact and connections before attributing an unexpectedly high threshold to tissue alone.

Worked example: At a fixed 0.5 ms pulse width and stable catheter position, 1.0 V captures on every stimulus, 0.8 V captures intermittently and 0.6 V never captures. The lowest tested output with consistent capture is 1.0 V at 0.5 ms. This is a measured bracket, not proof that the exact physiologic threshold is precisely 1.0 V.

Watch the distinction: Choosing 0.8 V because it captured once confuses occasional with reliable capture. A threshold statement must include the tested pulse width and contact conditions.

Reference: [1]

30. Measure baseline conduction intervals

Baseline intracardiac intervals separate portions of the atrioventricular conduction pathway. On the same captured beat, place the A cursor at the relevant atrial electrogram onset, H at the His deflection and V at the earliest appropriate ventricular activation. AH measures conduction from that atrial recording site through the AV node to His; HV measures conduction from His toward ventricular activation. Record the pacing or sinus condition because both interval interpretation and atrial recording location matter. Compare serial measurements on matched beats with unchanged recording settings. If AH increases while HV remains steady, the added delay is before the recorded His potential. If HV changes, investigate His-Purkinje conduction and cursor accuracy. For calculation practice after reviewing these signal definitions, the RCES practice questions provide a related exercise format.

Worked example: On one sinus beat, A begins at 120 ms, H at 215 ms and V at 260 ms. AH is 215 minus 120, or 95 ms; HV is 260 minus 215, or 45 ms. On a matched later beat, AH becomes 125 ms while HV remains 45 ms. The added 30 ms lies before the recorded His signal.

Watch the distinction: Measuring from an arbitrary atrial peak or comparing beats with different pacing conditions can create a false interval change. Cursor placement and beat context are part of the measurement.

Reference: [1]

31. Calculate corrected sinus node recovery time

Overdrive atrial pacing temporarily suppresses the sinus node. Sinus node recovery time is measured from the last paced atrial activation to the first clearly identified spontaneous sinus atrial activation after pacing stops. Corrected sinus node recovery time subtracts the patient’s baseline spontaneous sinus cycle length, estimating recovery beyond one ordinary cycle. The subtraction uses milliseconds on both sides: corrected recovery equals measured recovery interval minus baseline sinus cycle length. Confirm that the returning atrial beat is sinus rather than an ectopic atrial beat or an unrecognized paced response. Document the pacing rate and duration, which interval was longest, and the baseline rhythm used for correction. A single calculated value cannot by itself establish sinus node disease; symptoms, medications, autonomic state and the full protocol affect interpretation.

Worked example: After a documented overdrive pacing run, the longest interval from the last paced atrial activation to the first sinus atrial activation is 1,300 ms. The baseline sinus cycle length before pacing was 800 ms. Corrected recovery is 1,300 ms minus 800 ms, or 500 ms. Report 500 ms with the pacing conditions and confirm the returning beat’s sinus origin.

Watch the distinction: Subtracting from the last pacing stimulus rather than its captured atrial activation can skew the interval. Calling the result diagnostic without rhythm confirmation and clinical context overstates it.

Reference: [1]

32. Recognize AV nodal Wenckebach

Wenckebach behavior is a sequence, not merely one blocked beat. During progressively faster atrial pacing or a suitable rhythm, conduction through a decremental pathway may lengthen from beat to beat until an atrial impulse fails to reach the next recorded site. If atrial capture is confirmed, successive AH intervals lengthen, and the blocked atrial beat has no His potential, the observed failure lies before the recorded His signal. A stable HV interval in conducted beats supports the same localization. If a His potential appears without a ventricular response, the failure lies farther downstream. Check for missed atrial capture, concealed premature activity and ambiguous His signals before naming the block level. The RCES records the sequence, verifies stimulation and communicates the finding; the full clinical interpretation belongs in the procedure context.

Worked example: During atrial pacing, three captured atrial beats have AH intervals of 110, 145 and 180 ms, each followed by the same 45 ms HV interval. The next captured A has no H or V. The progressive AH increase of 35 ms per beat and absence of H on the blocked beat show Wenckebach behavior before the recorded His potential.

Watch the distinction: A missing ventricular beat does not automatically mean AV nodal Wenckebach. Without confirming atrial capture and whether a His potential occurred, the level of block remains uncertain.

Reference: [1]

33. Bracket an effective refractory period

An extrastimulus test uses a steady drive train, S1, followed by an earlier test stimulus, S2. Shortening the S1-S2 coupling interval probes when a tissue can no longer be captured or when a captured impulse can no longer conduct through a pathway. Those are different endpoints. To interpret the transition, keep drive cycle length, output, pulse width and catheter contact consistent, and confirm that each S2 actually captures its pacing site. The effective refractory period for a specified response is conventionally reported at the longest tested coupling interval that fails that response under the protocol. Testing in finite steps brackets the true transition rather than measuring it continuously. Record whether failure means atrial capture, AV conduction, ventricular capture or another defined endpoint, and note any changed rhythm or conduction history that could invalidate comparison.

Worked example: With the same drive train and confirmed atrial S2 capture, S2 at 350 ms conducts to His and ventricle; S2 at 340 ms produces an atrial electrogram but no His response. Tested in 10 ms steps, the AV conduction transition lies between 340 and 350 ms. The longest tested failing interval is 340 ms for this protocol; atrial refractoriness was not demonstrated.

Watch the distinction: Calling 340 ms the atrial capture refractory period would be wrong because the atrium captured. The observed failure concerns conduction beyond the atrial pacing site.

Reference: [1]

34. Read a wide-complex tachycardia cautiously

A wide QRS during tachycardia can arise from ventricular activation, supraventricular activation with abnormal intraventricular conduction, or pre-excitation. Start with the patient’s stability and the surface rhythm, then compare atrial and ventricular electrogram rates and relationships. More ventricular than atrial activations during a regular wide rhythm indicate AV dissociation and favor ventricular tachycardia. A narrow captured beat occurring amid wide beats further supports an intermittent supraventricular impulse reaching the ventricles during an otherwise ventricular rhythm. Morphology and prior QRS pattern can add evidence, but no isolated feature should be used without checking signal quality and timing. If instability accompanies the rhythm, communicate promptly and support the team response while documenting the observations. The RCES helps obtain dependable recordings and interpret their sequence, without independently making a treatment decision from one strip.

Worked example: During a regular wide-complex rhythm, ventricular electrograms occur at 150 per minute while atrial electrograms occur independently at 90 per minute. A single narrow beat appears when an atrial impulse reaches the ventricles. The excess ventricular rate, AV dissociation and capture beat favor ventricular tachycardia. Report the rhythm and the supporting signals immediately, especially if pressure is falling.

Watch the distinction: Calling every wide QRS ventricular tachycardia overlooks aberrancy and pre-excitation. Conversely, one apparent atrial deflection near a QRS does not establish that the atrium drives the rhythm.

Reference: [1]

35. Separate local from far-field electrograms

A near-field electrogram reflects depolarization close to the recording electrodes. On a bipolar pair it is often sharp, has a steep deflection and changes appreciably when contact or position changes. A far-field component comes from a more distant wavefront and can appear broadly on several adjacent pairs at similar times. Compare neighboring electrodes, unipolar and bipolar views when available, catheter movement and the known rhythm before selecting a timing marker. Amplitude alone is insufficient: poor contact can make a true local signal small, while a distant ventricular event can be large. For activation mapping, annotate the reproducible local component on comparable beats. If the component’s identity remains uncertain, record that uncertainty and obtain additional positions or pacing evidence before using the point to define a target.

Worked example: At a right atrial site, one contact pair has a sharp atrial deflection that shifts with a small catheter movement. A broad ventricular component appears at nearly the same time on four pairs. The spatially restricted, movement-sensitive atrial deflection is the better local atrial timing marker. Confirm contact and use that component consistently for nearby map points.

Watch the distinction: Marking the largest deflection as local can select a far-field ventricular signal. Locality depends on timing, spatial behavior and catheter contact, not amplitude alone.

Reference: [1]

36. Compare VA relationships in SVT

The ventriculoatrial, or VA, relationship describes when atrial activation follows ventricular activation during a tachycardia. A stable one-to-one VA pattern suggests the atrium and ventricle are linked in a reproducible sequence, but both AV nodal reentry and AV reentry through an accessory pathway can show it. Some atrial tachycardias can also produce an apparently stable relationship through conduction to the ventricle. The earliest atrial site helps locate the returning wavefront; an eccentric sequence near a suspected accessory connection raises that possibility without proving the circuit. Verify catheter location, timing reference and rhythm stability, then interpret pacing maneuvers that test whether ventricular activation is necessary to advance or sustain atrial activation. Report the evidence as a combined pattern and keep the mechanism provisional when alternative circuits still fit.

Worked example: During a narrow tachycardia, every ventricular electrogram is followed 90 ms later by an atrial electrogram. The earliest atrial recording lies near a suspected left-sided connection. Stable VA timing and eccentric atrial activation make AV reentry plausible. They do not establish it; the team should confirm catheter position and test the connection with an appropriately timed, captured pacing maneuver.

Watch the distinction: A fixed VA interval does not identify a unique SVT mechanism. Declaring an accessory pathway from timing alone ignores AV nodal reentry and atrial rhythms with consistent conduction.

Reference: [1]

37. Identify dual AV nodal physiology

During atrial extrastimulus testing, progressive shortening of S1-S2 often produces a gradual AH increase as AV nodal conduction slows. A disproportionate, abrupt AH increase after a small coupling change is an AH jump and supports dual AV nodal physiology: conduction may have shifted from a faster to a slower pathway. An atrial echo after the His and ventricular response suggests retrograde conduction returned activation to the atrium. Together, these findings make an AV nodal reentry circuit plausible, but they do not prove that a sustained clinical tachycardia uses it. Check that atrial capture, pacing site, drive cycle and annotation stayed constant. Describe the measured jump and echo precisely, then compare the induced tachycardia’s sequence and responses to pacing before assigning a mechanism.

Worked example: With identical drive trains, an S1-S2 interval of 330 ms yields AH of 180 ms. Shortening S1-S2 to 320 ms yields AH of 260 ms and one atrial echo. The coupling shortened 10 ms while AH increased 80 ms, a discontinuous response consistent with a pathway shift. The echo supports possible reentry; sustained tachycardia still needs separate assessment.

Watch the distinction: An AH jump is evidence of dual nodal conduction, not a diagnosis of AV nodal reentrant tachycardia. Annotation error or altered capture must be excluded before interpreting it.

Reference: [1]

38. Test for an accessory pathway

A retrograde accessory pathway can carry ventricular activation back to the atrium without using the usual His-AV nodal route. During tachycardia, a ventricular premature stimulus delivered while the His bundle is refractory is useful because a change in the next atrial activation is less readily explained by conduction through the refractory His system. Confirm ventricular capture, the stimulus timing relative to His refractoriness and the atrial activation sequence. If the stimulus advances the next atrial electrogram while preserving its sequence, that supports retrograde access to the atrium through an extranodal connection. It does not alone define the full tachycardia circuit; further pacing responses and the relationship of subsequent beats matter. An ineffective stimulus, uncertain His timing or a changed sequence weakens the inference and should be documented rather than forced into a diagnosis.

Worked example: During a stable tachycardia, a ventricular premature stimulus is delivered while the recorded His bundle is refractory. Ventricular capture is visible, and the next atrial electrogram occurs 25 ms earlier with the same atrial activation sequence. That response supports a retrograde accessory connection. Verify timing and capture on the stored trace before reporting the inference.

Watch the distinction: A stimulus marker alone does not prove ventricular capture. Without capture, an apparent atrial timing change cannot be attributed confidently to the intended ventricular premature beat.

Reference: [1]

39. Interpret a ventricular entrainment response

Ventricular entrainment tests how a tachycardia responds when ventricular pacing briefly drives the rhythm faster than its spontaneous cycle. Confirm that the paced beats capture the ventricle and determine whether the tachycardia is actually entrained rather than interrupted or replaced. After pacing stops, label the first genuine ventricular and atrial activations in order. A V-A-V return can support an AV-dependent mechanism such as AV nodal or AV reentrant tachycardia; a V-A-A-V pattern is more consistent with an atrial tachycardia continuing independently. The postpacing interval compared with the tachycardia cycle length can add information about circuit proximity, but its meaning depends on pacing site and conduction delays. Review the entire return sequence and other maneuvers before concluding a mechanism, because fusion, far-field signals or missed capture can create a misleading pattern.

Worked example: A tachycardia has a 360 ms cycle length. Ventricular pacing at a 340 ms cycle length produces confirmed ventricular capture and entrains the rhythm. After the last paced beat, the recorded return is ventricular, atrial, ventricular: V-A-V. This favors an AV-dependent tachycardia over an atrial tachycardia, but the team still compares activation sequence and other pacing evidence.

Watch the distinction: Reading the first postpacing atrial signal without proving ventricular capture can misclassify the return. A V-A-V label is useful only when the beats and entrainment are genuine.

Reference: [1]

40. Distinguish focal activity from reentry

A focal tachycardia starts from a source that repeatedly fires or triggers activation; reentry depends on a circulating wavefront with excitable tissue and conduction delay. Mechanism is inferred from several observations, not from regularity alone. Reproducible initiation after a premature beat, a consistent activation path and a timed stimulus that advances or delays subsequent beats without simply terminating the rhythm support a resettable circuit. Activation mapping can show whether local times progress around a loop, while pacing may show whether a site participates in that loop. A focal source can also be triggered by premature activity and may sometimes be reset, so those findings require careful comparison with activation pattern and return behavior. Verify that the stimulus captured the intended tissue and that the same tachycardia continued after the maneuver before describing a reset.

Worked example: A regular tachycardia repeatedly begins after a premature atrial beat. Sequential electrograms trace the same chamber route each cycle, and a captured stimulus delivered at a specific phase advances the next activation while the original sequence resumes. These findings favor a reentrant mechanism. They remain an inference until mapping and additional maneuvers exclude a focal source with similar timing.

Watch the distinction: Calling any premature-beat initiation proof of reentry is too strong. Triggered focal activity can begin that way; the continuing activation path and response to verified pacing supply the stronger evidence.

Reference: [1]

41. Use diagnostic maneuvers with context

A diagnostic maneuver is useful when you identify the tissue it perturbs and observe what continues afterward. Vagal stimulation and some clinician-directed drugs can slow or briefly block conduction through the AV node. If organized atrial activity continues at the same cycle length while ventricular responses disappear, the atrial rhythm can persist without ventricular activation. That observation helps distinguish an atrial rhythm from a tachycardia requiring the ventricle in its circuit. Record the atrial electrogram sequence before, during and after the maneuver; surface QRS disappearance alone cannot show whether atrial activity continued. A drug may also alter sinus rate, atrial refractoriness or blood pressure, so document its timing and the full response. The CCI RCES credential page includes differential diagnostic techniques in the role outline. The clinician chooses the maneuver; the RCES helps capture and communicate interpretable evidence.

Worked example: During a regular tachycardia, atrial electrograms recur every 300 ms. A clinician-directed maneuver produces two atrial activations without a following QRS, yet the atrial intervals remain 300 ms and the activation sequence is unchanged. AV conduction was transiently blocked while the atrial rhythm persisted. Document the blocked beats and subsequent recovery; this response argues against a circuit that requires each ventricular activation.

Watch the distinction: Calling the tachycardia terminated when QRS complexes vanish confuses ventricular response with the underlying rhythm. Check atrial electrograms before assigning a mechanism or outcome.

Reference: [1]

Performing Diagnostic Procedures: integrated decisions

42. Triangulate an ambiguous SVT

A stable ventriculoatrial interval says atrial activation follows ventricular activation consistently, but several supraventricular tachycardias can produce that pattern. Concentric atrial activation, earliest near the septum, helps describe the return route without identifying it uniquely. First verify that the apparent narrow tachycardia is genuine on surface and intracardiac channels, then measure its cycle length and VA interval using the same deflections each beat. During a ventricular pacing maneuver, confirm ventricular capture on every analyzed stimulus and establish whether atrial activation was directly captured. Only then interpret the return sequence. A V-A-V response after pacing supports an AV-dependent mechanism in the proper setting, yet additional maneuvers may be needed to separate AV nodal reentry from orthodromic AV reentry. Save the strips, timing markers and capture evidence so the operator can review the inference.

Worked example: A narrow tachycardia has a 340 ms cycle length, a reproducible 90 ms VA interval and earliest atrial activation at the septum. Ventricular pacing slightly faster than tachycardia captures each ventricle without direct atrial capture; the return sequence is V-A-V. Together, these findings favor an AV-dependent circuit. They do not, by themselves, identify whether AV nodal tissue or an accessory pathway supplies the retrograde limb.

Watch the distinction: Concentric atrial activation is often mistaken for proof of AV nodal reentry. A septal accessory pathway can produce a similar sequence, so preserve the pacing and timing evidence.

Reference: [1]

43. Use intracardiac echo to verify anatomy

Intracardiac echocardiography provides live anatomic context when catheter electrograms or a mapping shell leave position uncertain. Identify the interatrial septum, adjacent aortic root, atrial chambers and needle assembly before interpreting septal tenting. The image should be followed through movement and crossing because a single frame can miss a changed trajectory. After access, look for a new pericardial fluid collection and correlate it with pressure, heart rate and rhythm. A small image finding alone does not establish hemodynamic tamponade, while a growing collection with falling pressure demands immediate attention. Maintain accurate image orientation, communicate what structure is actually visible and preserve a baseline view for comparison. The operator makes the access and treatment decisions; the RCES supports imaging, recording and rapid recognition of a developing complication.

Worked example: Before crossing, ICE shows tenting at the intended interatrial region and no visible pericardial fluid. Shortly afterward, a new fluid rim appears and enlarges on repeat views. Arterial pressure falls from a stable 110/70 to 82/55 mmHg while the rhythm remains unchanged. Report the timed changes immediately and help the team reassess for bleeding or perforation.

Watch the distinction: A reassuring image of the needle before crossing cannot clear a new postaccess effusion. Repeat imaging and pressure trends describe the evolving event more accurately than the earlier view.

Reference: [1]

Assisting with Therapeutic Procedures

44. Support transseptal access

Transseptal support depends on confirming the assembly's path at each step: sheath and dilator position, septal engagement, needle crossing and left atrial entry. Imaging shows relationships to nearby structures; a properly zeroed pressure line helps identify the chamber entered. Blood color is unreliable because oxygenation and lighting can make venous and arterial blood look similar. After apparent crossing, compare the waveform with known atrial and systemic arterial traces before advancing equipment. A systemic arterial pattern raises concern for unintended arterial placement or a measurement error that must be resolved. Also watch for pressure decline, new effusion or rhythm change as access proceeds. The RCES should keep displays and images available, announce discordant findings promptly and support the operator's verification. Advancement should wait until the discrepancy is understood.

Worked example: After apparent septal crossing, the needle line reads 112/68 mmHg, closely matching a simultaneously measured radial arterial trace. Its waveform lacks recognizable atrial a and v components, although the aspirated blood looks bright. The waveform and color conflict with expected left atrial placement. Tell the operator, verify the line and transducer, and obtain imaging confirmation before further sheath movement.

Watch the distinction: Bright blood does not prove left atrial entry. Relying on its appearance while ignoring an arterial waveform risks advancing hardware into an unintended structure.

Reference: [1]

45. Build an activation map

An activation map assigns local electrogram times to locations using one stable reference, often a surface ECG feature or a fixed intracardiac signal. An earlier negative time means the annotated signal precedes that reference; it is useful only if the signal represents tissue under the mapping electrode. Inspect bipolar sharpness, unipolar shape where available, catheter contact, adjacent electrodes and beat morphology. Far-field activity can appear early across multiple sites without locating the source. Premature beats or variable tachycardia cycles also invalidate comparisons unless the map is gated to matching beats. Check the timing window and reference stability whenever an isolated point looks implausibly early. A credible early region should form a spatially coherent pattern with nearby validated points. The RCES supports point review and annotation; the operator integrates the map with anatomy and procedural risk.

Worked example: One point is annotated at minus 25 ms relative to QRS onset, and a neighboring point at minus 18 ms. The first deflection is broad, appears on several distant pairs and changes little with contact; the second is sharp and contact dependent. Although minus 25 ms is 7 ms earlier, exclude or reannotate that far-field point. The validated minus 18 ms site better represents local activation.

Watch the distinction: Selecting the most negative number automatically treats annotation as anatomy. A far-field or mismatched-beat timestamp can create a false earliest site and misdirect mapping.

Reference: [1]

46. Use pace and entrainment mapping

Pace mapping and entrainment mapping ask different questions. During pace mapping, compare the paced QRS with the clinical ventricular arrhythmia across multiple leads while confirming capture. A close match can suggest that pacing recruits a similar exit region, but nearby sites may produce similar QRS patterns. Entrainment tests a sustained circuit: pace slightly faster than tachycardia, confirm capture and assess the return after pacing stops. The postpacing interval is measured from the last captured pacing stimulus to the next local electrogram; compare it with the tachycardia cycle length in milliseconds. A small difference supports proximity to a circuit, subject to pacing site, capture and measurement limits. Concealed or manifest fusion and changes in tachycardia during pacing also matter. Neither maneuver alone proves a safe or effective ablation site.

Worked example: During a 320 ms ventricular tachycardia, pacing at one site produces a close match to the clinical QRS. At a second site, confirmed entrainment yields a 335 ms postpacing interval. The difference is 335 minus 320, or 15 ms, suggesting that the second site is near the circuit under the stated conditions. The QRS match addresses a possible exit; the interval addresses circuit proximity.

Watch the distinction: A matching paced QRS does not establish that the pacing electrode lies in the critical circuit. Likewise, a short return interval needs verified capture and a stable tachycardia.

Reference: [1]

47. Explain radiofrequency lesion formation

Radiofrequency energy heats tissue next to an electrode as current encounters electrical resistance. Heat then spreads into deeper tissue by conduction, so lesion formation depends on contact, power, duration, irrigation and local blood flow. Console power describes electrical delivery, not the exact thermal dose received by a target. Weak or shifting contact may leave little effective heating even as elapsed time accumulates. Excessive heating can cause abrupt impedance change, coagulum or steam formation; the displayed electrode temperature may not equal the hottest tissue temperature, especially with irrigation. Relate local electrogram change and contact information to the energy trace rather than interpreting either alone. The RCES operates and monitors equipment within the team's procedure, reports unstable contact or unexpected parameter trends and helps preserve a clear record of where and when energy was delivered.

Worked example: A hypothetical application delivers 20 W for 15 s, equivalent to 300 J of electrical energy because 1 W equals 1 J/s. The catheter slips repeatedly and the local electrogram remains unchanged. Those 300 J do not establish a useful lesion at the intended site. Report the unstable contact and review catheter position before the operator considers another application.

Watch the distinction: Longer delivery is not a reliable substitute for contact. It can add risk while the target receives inconsistent heating, and total joules cannot specify lesion depth.

Reference: [1]

48. Interpret ablation parameters together

Ablation parameters become meaningful as a synchronized trend. Note when delivery starts, whether catheter contact and location remain stable, and how power, temperature, impedance and local electrograms change together. A gradual change may reflect evolving tissue heating, while a sudden impedance rise or distorted signals can indicate poor coupling or excessive heating and requires immediate assessment. Irrigated and nonirrigated electrodes show different temperature behavior, so the console temperature cannot be interpreted without the catheter type. A loss of arrhythmia or local signal may show effect, but it cannot alone establish lesion durability. Keep the recording, mapping location and generator timeline aligned so the operator can distinguish a tissue response from artifact, catheter movement or a connection problem. The RCES should promptly call out concerning changes and carry out the team's energy-control direction.

Worked example: At a steady displayed 25 W, impedance rises from 110 to 145 ohms within seconds, a 35 ohm increase, while the local electrogram distorts. The simultaneous abrupt changes warrant concern for overheating or a technical fault. Announce the trend immediately, support stopping or adjusting energy as directed, and inspect the catheter and recording before further delivery.

Watch the distinction: Waiting for the programmed application time to finish ignores a new safety signal. Preset duration is a limit on planned delivery, not evidence that conditions remain safe.

Reference: [1]

49. Distinguish cryoablation from RF delivery

Cryoablation removes heat from tissue, altering cell function during cooling and producing lasting injury when a sufficient freeze is achieved. Early conduction effects may reverse with rewarming, which can help assess a target near sensitive conduction tissue; reversibility is not guaranteed. Radiofrequency delivery heats tissue and has a different response pattern and set of energy warnings. During either method, follow the rhythm, local electrograms, catheter stability and the function of nearby structures. For cryoenergy near AV conduction tissue, changes in AH, His-to-ventricle conduction or ventricular response deserve immediate communication, even if the desired tachycardia stops. At sites near the phrenic nerve, loss of diaphragmatic capture or motion may indicate injury risk. The operator determines whether to continue or terminate energy; the RCES supplies timely measurements and observations.

Worked example: During cooling near an AV conduction target, the tachycardia stops. On the next conducted beats, the AH interval rises from 90 to 150 ms while the HV interval remains 45 ms. The 60 ms increase localizes the observed slowing above the recorded His signal. Announce the change immediately so the operator can reassess energy delivery and follow recovery during rewarming.

Watch the distinction: Termination of the target rhythm does not make the application automatically acceptable. New AV conduction delay may signal injury to nearby tissue and must be reported promptly.

Reference: [1]

50. Support a pacemaker implant

A pacemaker lead must deliver current to myocardium, detect intrinsic activity and remain electrically connected after the pocket is closed. Test capture at a fixed pulse width while reducing output to find the lowest consistently capturing tested setting; document the conditions. Measure sensed intrinsic amplitude separately because a lead may capture but sense poorly. Impedance helps assess the lead and connection, with abrupt deviation prompting inspection, though one value cannot identify every fault. Fluoroscopy or other imaging shows the lead course, while electrical testing and observation during appropriate movement help reveal instability. Check the final programmed output against the tested capture behavior and confirm the observed paced rhythm. The RCES records and conveys lead measurements, assists troubleshooting and flags discordance before closure; the implanting clinician decides lead placement and programming.

Worked example: A new ventricular lead consistently captures at a tested 1.0 V output with a 0.4 ms pulse width. Its intrinsic sensed amplitude then falls sharply when the patient's arm is repositioned, and the lead tip shifts on imaging. Good capture at one position does not settle lead stability. Report the combined electrical and imaging changes and repeat testing after the operator reassesses position.

Watch the distinction: A low capture threshold is only one part of lead evaluation. It cannot compensate for unstable sensing, an abnormal connection or lead movement after the initial test.

Reference: [1]

51. Differentiate ICD and subcutaneous ICD checks

A transvenous ICD typically uses an intracardiac lead to sense ventricular rhythm, deliver shock therapy and, when configured, provide bradycardia pacing or antitachycardia pacing. A conventional subcutaneous ICD senses through a subcutaneous electrode and delivers defibrillation without a chronic transvenous pacing lead. Its usual configuration does not supply ongoing bradycardia pacing or standard antitachycardia pacing. That distinction matters before device selection and when investigating a reported pacing need. For a transvenous system, review lead sensing, capture where applicable, impedance, stored episodes and programmed therapies. For a subcutaneous system, review sensing vectors, stored detections and system integrity, including the surface ECG relationship. The RCES supports interrogation and communicates limitations and findings; device choice and therapy programming remain clinician decisions based on the whole patient.

Worked example: A patient being considered for a subcutaneous ICD has recurrent documented bradycardia for which the treating clinician is evaluating ongoing pacing. The proposed device can provide defibrillation, but its usual configuration lacks chronic bradycardia pacing. Flag the mismatch before implantation and provide the rhythm and device information for clinician review. The defibrillation indication alone does not resolve the pacing requirement.

Watch the distinction: Assuming every ICD can pace like a transvenous pacemaker overlooks the subcutaneous system's usual limitations. Confirm device architecture before explaining its available therapies.

Reference: [1]

52. Assess a CRT system

Cardiac resynchronization therapy aims to activate the ventricles in a coordinated programmed pattern. Confirm right and left ventricular lead function separately, then assess whether both ventricles are actually captured at the programmed outputs and timing. A device counter may count delivered pacing pulses even when one lead intermittently fails to capture or fusion with intrinsic conduction changes the resulting activation. Compare surface QRS morphology, intracardiac electrograms and lead tests with the intended AV and interventricular timing. Also inspect impedance and sensed signals for clues to lead or connection problems. Effective pacing should be assessed in the rhythm and conditions the patient is likely to experience, because capture may vary with posture or rate. The RCES documents the discrepancy and supports retesting; the clinician determines programming or lead changes.

Worked example: A programmer reports biventricular pacing on 96% of recent cycles. During testing at the current settings, the left ventricular lead fails to capture on several stimuli, while right ventricular capture remains consistent. The 96% counter describes delivered pacing events, not proven effective biventricular activation. Report the intermittent loss, record the tested outputs and rhythm, and support repeat lead assessment before accepting the result.

Watch the distinction: A high biventricular pacing percentage does not prove resynchronization when a lead loses capture. Verify electrical capture and the resulting activation pattern.

Reference: [1]

53. Prepare for lead extraction hazards

Chronically implanted leads can become bound by fibrous tissue along veins, the superior vena cava and cardiac structures. Extraction therefore can tear a vessel or heart wall even when the lead initially moves freely. Before the procedure, verify that invasive pressure, ECG and oxygenation monitoring are reliable and that the agreed surgical, transfusion and resuscitation resources are ready. During traction or sheath advancement, relate abrupt pressure, rhythm and oxygenation changes to the procedural moment. Hypotension with tachycardia may suggest hemorrhage; new pericardial fluid can point toward cardiac injury, while either observation requires rapid confirmation and team response. Maintain clear time-stamped records and communicate changes aloud. The RCES prepares and monitors equipment and supports the emergency plan; procedural rescue decisions belong to the responsible clinicians.

Worked example: During extraction of an old ventricular lead, arterial pressure falls from 118/72 to 78/48 mmHg and heart rate rises from 75 to 112 beats/minute. The pressure drop is 40 mmHg systolic, occurring immediately after sheath advancement. Verify the tracing, announce the timed change and help activate the prepared response for possible vascular or cardiac injury while monitoring continues.

Watch the distinction: Attributing sudden hypotension to sedation without considering extraction timing can delay recognition of bleeding. Verify the measurement while alerting the team to the change.

Reference: [1]

Assisting with Therapeutic Procedures: integrated decisions

54. Check left atrial appendage closure support

Left atrial appendage closure support requires several complementary observations before device release. Fluoroscopy shows the device frame, orientation and gross movement, while echocardiography shows the appendage opening, device relationship to tissue, adjacent structures and color-flow channels. Compare the deployed configuration with the operator's intended position in multiple views, then document stability assessment and any residual flow seen on imaging. A channel around an edge may reflect incomplete apposition, imaging angle or another issue requiring reassessment; one image cannot settle the mechanism. The RCES keeps imaging, pressure and rhythm data available, records the assessment sequence and promptly conveys disagreement between views. Device sizing, release and acceptance of any residual flow are clinician decisions made from the complete procedural assessment.

Worked example: Fluoroscopy shows a closure device that appears aligned and stable in one projection. Echo from a second view shows color flow passing around one edge into the appendage. The views answer different questions: the frame appears positioned, but sealing remains uncertain. Report both findings before release and help obtain the additional views or measurements the operator requests.

Watch the distinction: A stable fluoroscopic silhouette does not prove an adequate seal. Color-flow and anatomic findings must be reconciled before the device is accepted.

Reference: [1]

55. Coordinate a complication response

A complication response starts by connecting the event sequence with simultaneous physiologic evidence. After left atrial ablation, falling arterial pressure plus a newly enlarging pericardial collection raises concern for bleeding into the pericardial space and impaired filling. Confirm that the pressure trace is valid, but communicate the concern immediately rather than waiting for every finding to develop. Continue ECG and pressure surveillance, note any tachycardia or conduction change, and prepare the equipment requested for drainage and circulatory support. Maintain sterile access to rescue supplies and record the time of energy delivery, first pressure change and imaging findings. An effusion may have other causes and its size alone does not define hemodynamic effect; the combined trend determines urgency. The RCES supports the team's response without independently diagnosing or performing the intervention.

Worked example: Two minutes after left atrial energy delivery, arterial pressure declines from 108/66 to 76/50 mmHg. ICE shows a pericardial collection that is larger on repeat imaging, while the recording system confirms a sustained pressure decline. Announce the findings and timing, prepare pericardiocentesis supplies as directed, and continue rhythm and pressure monitoring while clinicians manage circulation.

Watch the distinction: Treating the pressure decline as an isolated monitor error ignores the growing fluid collection. Verify the trace promptly while preparing for the likely emergency.

Reference: [1]

Conducting Post-Procedural Activities

56. Reconcile postprocedure measurements

Postprocedure measurements need a before-and-after comparison tied to what changed in the lab. Record the final rhythm, blood pressure, oxygenation, relevant laboratory results and administered medications with their times. For a cardiac implantable electronic device, include final mode, programmed settings, lead measurements, alerts and any planned repeat interrogation. A newly paced surface pattern may be expected after programming, but recovery staff need the actual settings and observed rhythm to identify later deviation. Interpret a pressure or laboratory change alongside bleeding, fluids, sedation and anticoagulation history instead of describing it as an isolated number. State whether each finding was verified and which checks remain pending. For broader rhythm and hemodynamic context, the cardiac medicine certification guide is related reading; the RCES handoff must still carry procedure-specific device data.

Worked example: Before programming, a patient's intrinsic rate is 58 beats/minute and pressure is 116/70 mmHg. The new device lower rate is set to 70 beats/minute; the final strip shows consistent pacing at 70 beats/minute with pressure 114/68 mmHg. Record the setting, rhythm and pressure together. Recovery staff can then compare a later rate change with this documented baseline.

Watch the distinction: Writing only “paced and stable” hides the programmed rate and measured pressure. The receiving team needs numbers and timing to recognize a new change.

Reference: [1]

57. Confirm hemostasis and perfusion

Hemostasis and limb perfusion are related checks after femoral access. Inspect the dressing and surrounding tissue for active bleeding, swelling or expanding firmness, and compare distal pulses, temperature, color and sensation with the preprocedure or opposite-side findings. A closure device or dry dressing describes the puncture site; neither guarantees unobstructed distal flow. Conversely, a weak palpable pulse may reflect baseline disease or measurement difficulty, so verify the change and use an available Doppler assessment when appropriate. Escalate a new perfusion deficit promptly while continuing pressure and site surveillance. Document the access side, closure method, assessment time and exact change. The RCIS study guide offers related vascular access context; in EP recovery, multiple venous or arterial sites may each need separate assessment.

Worked example: Thirty minutes after femoral access closure, the dressing is dry. The affected foot is cooler than at the preprocedure check, and its previously palpable distal pulse is now difficult to find; the other foot is unchanged. Recheck the pulse and site, report the new asymmetry promptly and obtain the team's reassessment. A dry dressing does not resolve the perfusion concern.

Watch the distinction: Equating a dry dressing with complete recovery overlooks vessel obstruction or impaired limb flow. Assess the access site and distal limb as separate observations.

Reference: [1]

58. Detect evolving postprocedure complications

Recovery surveillance must follow the hazards of the procedure and the patient's evolving findings. Check access sites for delayed bleeding, trend pressure and rhythm for hemodynamic or conduction changes, and compare neurologic status with the preprocedure baseline. After left atrial work, a new focal neurologic deficit demands immediate escalation because cerebral injury is possible even when pressure and groin checks remain normal. Following ablation near conduction tissue, a new slow rhythm or AV block deserves prompt assessment; after device work, loss of capture or a new alert may signal an equipment or lead problem. Record the exact onset, last known normal state and accompanying rhythm and vital signs. The RCES detects and communicates changes, supports monitoring and handoff, and follows the responsible clinical team's emergency response.

Worked example: After a left atrial procedure, a patient who spoke normally at 14:10 develops new right arm weakness and slurred speech at 14:25. Blood pressure remains 112/70 mmHg and both groin sites are dry. Document the last normal and first abnormal times, alert the team immediately and continue rhythm and vital-sign monitoring. Normal access sites do not explain the neurologic change.

Watch the distinction: Waiting for bleeding or hypotension before escalating focal weakness delays evaluation of a separate complication. A new neurologic deficit is significant on its own.

Reference: [1]

59. Make patient teaching specific

Useful teaching names the patient's actual access or implant site, the agreed recovery plan and symptoms that require action. After a device implant, explain how the team wants the wound observed, what device alerts may look or sound like, and whom the patient should contact if an alert occurs. New syncope, severe dizziness, chest symptoms, fever or concerning wound changes should be tied to the discharge team's escalation instructions. After vascular access, include the specific site and what to do for bleeding, swelling or a new limb change. Avoid giving a universal movement restriction or follow-up schedule when the patient's plan may differ. Ask the patient to repeat the key actions in their own words, correct gaps and document what was understood. The RCES reinforces the team's instructions and reports unanswered concerns before discharge.

Worked example: A patient after pacemaker implantation accurately repeats wound-care instructions but says they would ignore a device alert and “sleep off” a fainting episode. Review the written plan with the patient: identify the contact route for an alert and the urgent response specified for syncope. Ask for a second teach-back, then document the corrected understanding and any remaining questions.

Watch the distinction: A patient who understands wound care may still lack an emergency plan. Verify what they will do for symptoms and device alerts, not just how they will inspect the incision.

Reference: [1]

60. Close the loop at handoff

A safe transfer joins the final bedside assessment with a concise account of what occurred. State the procedure, final rhythm and vital signs, access or wound sites, hemostasis method, distal perfusion findings, medications that affect recovery and any complications or interventions. For a device procedure, give the final programmed settings, observed capture or sensing concerns and alerts. Pending checks need an owner and expected follow-up, because “pending” without responsibility can disappear during transfer. Compare the patient's current condition with the documented preprocedure baseline and identify changes that need surveillance. Deliver the information to the receiving clinician, confirm acknowledgment of time-sensitive issues and record the handoff. The RCES contributes technical and physiologic details while the responsible team retains clinical decisions and orders.

Worked example: At transfer after device programming, pressure is 118/72 mmHg, the groin dressing is dry and the final strip shows ventricular pacing at 70 beats/minute. A repeat interrogation remains pending because of an earlier sensing alert. Tell recovery staff the final programmed lower rate, observed rhythm, access findings and alert history; identify who will obtain and review the repeat interrogation.

Watch the distinction: Reporting only stable pressure and a dry groin omits the unresolved device check. A complete handoff assigns the pending interrogation and preserves the final rhythm for comparison.

Reference: [1]

Official references and further reading

Registered Cardiac Electrophysiology Specialist exam with CCI

All study guides

Conducting Pre-Procedural Activities

1. Match the room to the planned procedure

2. Reconcile the record and procedure plan

3. Verify identity through transport

4. Prepare monitoring and implanted devices

5. Prepare the site without breaking sterility

Conducting Intra-Procedural Activities

6. Track comfort alongside sedation

7. Interpret a change in vital signs

8. Recognize medication effects on EP findings

9. Support vascular access safely

10. Trend anticoagulation measurements

11. Connect glucose and blood gas results to monitoring

12. Read the device interrogation summary

13. Separate capture, sensing and lead integrity

14. Decode a pacing mode

15. Match equipment to procedure phase

16. Respond to a sterile-field breach

17. Set up a trustworthy EP recording

18. Operate the stimulator with capture checks

19. Trace noise through the signal chain

20. Know what filters can hide

21. Build a stable 3D mapping reference

22. Judge whether a mapping point is valid

23. Reduce radiation exposure

24. Use fluoroscopic views to resolve depth

25. Combine radiographic and nonradiographic images

26. Protect against electrical and fire hazards

27. Recognize an intra-procedure emergency

Performing Diagnostic Procedures

28. Identify diagnostic catheter locations

29. Find a pacing capture threshold

30. Measure baseline conduction intervals

31. Calculate corrected sinus node recovery time

32. Recognize AV nodal Wenckebach

33. Bracket an effective refractory period

34. Read a wide-complex tachycardia cautiously

35. Separate local from far-field electrograms

36. Compare VA relationships in SVT

37. Identify dual AV nodal physiology

38. Test for an accessory pathway

39. Interpret a ventricular entrainment response

40. Distinguish focal activity from reentry

41. Use diagnostic maneuvers with context

Performing Diagnostic Procedures: integrated decisions

42. Triangulate an ambiguous SVT

43. Use intracardiac echo to verify anatomy

Assisting with Therapeutic Procedures

44. Support transseptal access

45. Build an activation map

46. Use pace and entrainment mapping

47. Explain radiofrequency lesion formation

48. Interpret ablation parameters together

49. Distinguish cryoablation from RF delivery

50. Support a pacemaker implant

51. Differentiate ICD and subcutaneous ICD checks

52. Assess a CRT system

53. Prepare for lead extraction hazards

Assisting with Therapeutic Procedures: integrated decisions

54. Check left atrial appendage closure support

55. Coordinate a complication response

Conducting Post-Procedural Activities

56. Reconcile postprocedure measurements

57. Confirm hemostasis and perfusion

58. Detect evolving postprocedure complications

59. Make patient teaching specific

60. Close the loop at handoff

Official references and further reading

Frequently Asked Questions

Related Study Guides

Registered Cardiovascular Invasive Specialist (RCIS)

Psychiatric-Mental Health Nurse Practitioner (PMHNP-BC)

Certified Pediatric Nurse Practitioner - Acute Care (CPNP-AC)