Right Ventricular Pacing
Can More of a Bad Thing Be Good?
This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.
See Article by Cronin et al
Implantable cardioverter–defibrillators (ICDs) have been shown to prolong life both in the setting of secondary prevention after a malignant ventricular arrhythmia and primary prevention in patients with a severely reduced left ventricular ejection fraction (LVEF). As with most therapies, the overall benefit of the ICD is a balance between its beneficial and detrimental effects. Termination of malignant ventricular arrhythmias is clearly the primary benefit of the ICD. Unfortunately, as we study outcomes in patients with pacemakers and ICDs, we have identified potential adverse effects that may counterbalance the beneficial effects. It has become increasingly apparent that the ICD shocks that terminate ventricular tachyarrhythmias can not only prevent a sudden death but also paradoxically increase the subsequent risk of death primarily via progression of heart failure. Programming interventions that lead to the withholding of ICD shocks for all but the fastest and more sustained ventricular arrhythmias have been shown to reduce the overall risk of death among ICD recipients. Similarly, though some patients might have severely symptomatic bradycardia or pauses without ventricular pacing from a pacemaker or ICD, this pacing itself, especially when it occurs too frequently, can lead to many important adverse outcomes, including atrial fibrillation, new or worsened heart failure, and increased mortality.1–4
In this issue, Cronin et al5 show an association between increased right ventricular (RV) pacing and an increased risk of the need for an appropriate ICD shock. With higher percentages of cumulative and weekly RV pacing, there was a trend toward an increased risk that a patient would receive a shock, although this risk, when compared with that associated with <1% RV pacing, did not become statistically significant until …