Cardiac Resynchronization Therapy and its Potential Proarrhythmic Effect

Abstract

SummaryCardiac resynchronization therapy (CRT) has become an established adjunctive treatment to optimal pharmacologic therapy in patients with advanced chronic heart failure (CHF), diminished left ventricular (LV) function and intraventricular conduction delay. Although CRT has been shown to improve ventricular hemodynamics, quality of life and exercise capacity, there is some evidence that it may rarely potentiate ventricular arrhythmias. As CRT is considered for an expanded population of CHF patients, and left-sided pacing is considered as an option for pacemaker-indicated patients (potentially without defibrillator backup), the effect of these pacing modalities on the incidence of ventricular tachyarrhythmia must be systematically studied and mechanistically understood. Strategies to prospectively predict the proarrhythmic potential of LV epicardial pacing need to be developed, and therapy accordingly individualized. This review attempts to summarize the current information on proarrhythmia in resynchronization therapy.

A Critical Appraisal of Implantable Cardioverter-Defibrillator Therapy for the Prevention of Sudden Cardiac Death

“…Alternatively, insertion of the device may be directly or indirectly proarrhythmic. There are numerous speculated mechanisms by which an ICD may promote arrhythmogenesis including device malfunction, induction of arrhythmias from inappropriate shocks, pacemaker-facilitated triggers, and reversal of activation wavefronts from epicardial resynchronization increasing dispersion of refractoriness (31)(32)(33)(34)(35). Additionally, local lead effects with mechanical irritation and late fibrosis may be a potential mechanism for VT (Fig.…”

Ventricular arrhythmia storm in the era of implantable cardioverter-defibrillator

“…However, there have been case series demonstrating the potential proarrhythmic effects of CRT devices 39. The proposed mechanisms include increased dispersion of refractoriness, prolonged QT interval and atypical autonomic response 39. The LV lead may induce premature ventricular contraction triggers or activate scar-related regions of slow conduction to facilitate re-entry.…”

Managing patients with ICD shocks and programming tachycardia therapies during acute heart failure syndromes

“…However, case reports and case series have demonstrated the potential proarrhythmic effects of biventricular devices [38, 39]. These events are relatively rare, and proposed mechanisms include increased dispersion of refractoriness, prolonged QT interval, and atypical autonomic response.…”