Atrial Pace on PVC Algorithm Inducing Ventricular Fibrillation

Abstract

proarrhythmia, PVC response, implantable cardiovertor defibrillator, atrial pace on PVC Case PresentationA 62-year-old man presented to the hospital following an episode of syncope and implantable cardiovertor defibrillator (ICD) shock. He was known to have ischemic cardiomyopathy, prior coronary artery bypass grafting in 2007, and a dual-chamber ICD, a Current Accel DR (St. Jude Medical, Inc., Minneapolis, MN, USA) implanted in 2009 following a ventricular fibrillation (VF) arrest.Device interrogation revealed a VF episode that was successfully terminated with a 36-J shock. Testing of the atrial and ventricular leads demonstrated adequate pace/sense function and normal lead impedances. Device parameters were as follows: DDD mode with a base rate of 40 beats per minute (rate response sensor was passive), postventricular atrial refractory period (PVARP) was 275 ms, ventricular intrinsic preference (VIP) was enabled and programmed to 100-ms extension (a setting to prolong the atrioventricular [AV] delay and permit intrinsic conduction), and premature ventricular contraction (PVC)/pacemakermediated tachycardia responses were enabled. Tachycardia detection was set to three zones, with the ventricular tachycardia 1 (VT1) zone starting at 375 ms, VT2 starting at 320 ms, and VF zone starting at 280 ms. Therapy was programmed with antitachycardia pacing followed by shocks in the first two zones and shocks only in the VF zone. The presenting episode is shown in Figure 1. What is the most likely mechanism of initiation of this VF episode; is it likely related to the underlying Conflict of interest:

The limitations and potential adverse effects of the premature ventricular contraction response

“…Although pacing-induced ventricular fibrillation is rare, the potentially life-threatening risk should not be underestimated. 2,3 In the present case, PVC response was turned off, which successfully rendered ventricular spikes on T-wave undetectable. This case highlights the limitations and potential adverse effects of such automated algorithms as PMT prevention/intervention, which could have resulted in ventricular proarrhythmia.…”

“…As demonstrated in the present case, PVC response may have a potential risk of ventricular pacing on the T‐wave, especially in the setting of atrial tachyarrhythmia with oscillation and AV conduction prolongation. Although pacing‐induced ventricular fibrillation is rare, the potentially life‐threatening risk should not be underestimated . In the present case, PVC response was turned off, which successfully rendered ventricular spikes on T‐wave undetectable.…”

Premature ventricular contraction response-induced new-onset atrial fibrillation

“…In the current case, the PVC response algorithm resulted in a short interval between the atrial activity late within the PVARP and the PVC response commanded atrial pacing, resulting in a long–short sequence and tachycardia. Although a previous report showed that the patient’s algorithm can induce ventricular arrhythmias via induction of a long–short sequence, 2 this represents the first report in the literature of this mechanism of AF initiation. Atrial pacing must occur at a critical time relative to the intrinsic atrial activity in order to set up functional reentry and fibrillatory activity.…”

Novel findings of an old algorithm: PVC response “Atrial Pace’’ initiates atrial arrhythmias in Abbott ICD and CRT‐D devices

“…Thus, there are numerous patients who may be affected by this programming. Although PVC response is nominally programmed Off, in our representative cohort this A‐Pace on PVC was used in half of the patients and the previous case reports from US, 5,6 Canada 12 , China 7 , and Japan 13 indicate that this programming has been used frequently around the world. Nevertheless, the clinical significance of our findings needs further evaluation.…”