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EKG Pop Quiz

Michael Giocondo, MDCardiac ElectrophysiologySaint Luke’s Cardiovascular Consultants

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No financial relationships to disclose.

DisclosuresEKG #175 y/o woman with a dual-chamber pacemaker implanted for SSS presents for her annual visit. Symptoms: None. Programming: DDDR 60-130 bpm.

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EKG #1: The Pacemaker Behavior Noted is BestDescribed as…1) Atrial pacing with capture. Normal device function.

2) Ventricular pacing with capture. Normal device function.

3) Atrial and ventricular pacing with capture. Normal device function.

4) No evidence of pacing. Normal device function.

5) No evidence of pacing. Abnormal device function.

EKG #1: Explanation- This EKG demonstrates normal sinus rhythm at 84 bpm with no

evidence of either atrial or ventricular pacing.- Normal pacemaker behavior in DDDR mode is to inhibit pacing

if the intrinsic rhythm is above the lower rate limit.- This behavior limits battery usage by preventing unnecessary

pacing.- In addition, preventing excess unneeded right ventricular

pacing prevents development of a pacing-induced cardiomyopathy caused by dyssynchronous ventricular activation related to right ventricular-only pacing.

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EKG #282 y/o man with a dual-chamber pacemaker implanted for CHB 10 years ago presents for an urgent visit due to symptoms of dyspnea. Programming: DDDR 60-120 bpm.

EKG #2 – EKG Obtained 1 Year Prior82 y/o man with a dual-chamber pacemaker implanted for CHB 10 years ago presents for an urgent visit due to symptoms of dyspnea. Programming: DDDR 60-120 bpm.

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EKG #2: The Pacemaker Behavior Noted is Best Described as…1) Atrial pacing with capture, normal device function

2) Ventricular pacing with capture, normal device function

3) Atrial and ventricular pacing with capture, normal device function

4) Abnormal device function

EKG #2: Explanation- This EKG demonstrates sinus rhythm with asynchronous, non-

physiologic ventricular pacing at 65 bpm.- This behavior is normal for a pacemaker device that has

reached elective replacement indicator (ERI), A.K.A. recommended replacement time (RRT) status.

- The device reverts to VVI mode with ventricular pacing at a fixed rate without rate-response.

- With pacing the ventricular only, device battery drain related to dual-chamber pacing is avoided.

- Patients are often symptomatic with fatigue, dyspnea, and palpitations due to “pacemaker syndrome’.

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EKG #377 y/o man with a dual-chamber pacemaker implanted for SSS presents for an annual visit. Symptoms: intermittent palpitations. Programming: DDDR 60-120 bpm.

EKG #3: The Pacemaker Behavior Noted is Best Described as…1) Atrial pacing with capture, normal device function

2) Ventricular pacing with capture, normal device function

3) Atrial and ventricular pacing with capture, normal device function

4) Abnormal device function

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EKG #3: Explanation- This EKG demonstrates an atrial and ventricular paced rhythm

with intermittent AV delay prolongation.- This pacemaker behavior is normal and is related to an an

advanced algorithm that allows for extension of the atrioventricular delay in order to allow prolonged conduction through the native conduction system.

- This algorithm provides back-up ventricular pacing triggered after the prolonged AV delay expires.

- All pacemaker brands employ similar algorithms to prevent unnecessary RV pacing and to promote battery longevity.

EKG #3: Explanation

Note Variable Atrioventricular Delay

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EKG #489 y/o woman with a dual-chamber pacemaker implanted for CHB post TAVR who presents for a routine visit. Symptoms: None. Programming: DDDR 60-120 bpm.

EKG #4 – EKG Before Pacemaker Implant89 y/o woman with a dual-chamber pacemaker implanted for CHB post TAVR who presents for a routine visit. Symptoms: None. Programming: DDDR 60-120 bpm.

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EKG #4 – Compare Before and After QRS Complexes89 y/o woman with a dual-chamber pacemaker implanted for CHB post TAVR who presents for a routine visit. Symptoms: None. Programming: DDDR 60-120 bpm.

Before Pacer After Pacer

EKG #4: The Pacemaker Behavior Noted is Best Described as…1) Atrial pacing with capture, normal device function

2) Ventricular pacing with capture, normal device function

3) Atrial and ventricular pacing with capture, normal device function

4) Abnormal device function

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EKG #4: Explanation- Atrial and ventricular pacing with capture is noted.- The unique feature noted here is the unusually narrow paced

QRS complex of ## msec related to His bundle pacing.- His bundle pacing allows the pacing stimulus to directly enter

the conduction system or its surrounding tissue in order to provide more physiologic pacing vs. right ventricular apical pacing.

- This newer technique has been shown to decrease heart failure symptoms in relatively small research studies.

- Large research studies comparing this technique to standard right ventricular apical pacing are being discussed.

EKG #4: Explanation

His Bundle Pacing: Lead Positioning

RA

His

RV

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EKG #571 y/o woman with a dual-chamber pacemaker implanted for CHB who presents for a urgent visit because of intermittent lightheadedness. Programming: DDDR 60-120 bpm.

EKG #5: The Pacemaker Behavior Noted is Best Described as…1) Atrial pacing with capture, normal device function

2) Ventricular pacing with capture, normal device function

3) Atrial and ventricular pacing with capture, normal device function

4) Abnormal device function

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EKG #5: Explanation- The intermittent pauses noted are related to pacemaker

sensing of electrical “noise” from a lead fracture.- Pacemakers are not readily able to differentiate lead “noise’

from normal intrinsic cardiac electrical activity.- This patient required urgent pacemaker lead revision with

addition of a new right ventricular lead.- Pacemaker lead fracture may also cause pacing output failure.

This may be difficult to diagnose, so pacemaker-dependent patients with symptoms of lightheadedness, near-syncope or syncope should be thoroughly evaluated.- Lead impedance and threshold testing, pocket manipulation, isometric maneuvers, ambulatory

monitoring, and chest x-ray.

EKG #5: Explanation

Electron Microscope View of Lead Fracture Grossly Fractured Pacemaker Lead

Intracardiac EGM:Pacing Inhibition From Lead “Noise”