Uncommon Sense: What Does This Aberrant Pacing Spike Indicate?
Texas Heart Institute Journal
A 76-year-old woman with a history of coronary artery disease, end-stage renal disease, and intermittent 2nd-degree (Mobitz II) atrioventricular (AV) block was admitted after an unwitnessed fall. She reported no symptoms during the episode. She had an Accent DR RF dual-chamber pacemaker (model PM2210) with Tendril STS Model 2088TC atrial and ventricular bipolar leads (all from St. Jude Medical, part of Abbott). The pacemaker was set in DDDR mode (pacing rate, 60-120 beats/min). Its programmed
... in). Its programmed paced AV interval was 200 ms, and the sensed interval, 190 ms. Its Ventricular AutoCapture Pacing System, atrial and ventricular SenseAbility AutoSense function, and ventricular safety pacing were activated. The patient had an abnormal rhythm overnight, and her telemetry results were atypical (Fig. 1) . Interrogation revealed normal device function and no aberrant event stored in memory. What most likely caused the atypical tracing? A) Device threshold search B) Oversensing C) Ventricular safety pacing D) Accelerated idioventricular rhythm with ventricular undersensing (in the 6th complex from right of the tracing)