The Impact of Cardiac Resynchronization Therapy on the Frequency of Ventricular Arrhythmias

Background: Cardiac resynchronization therapy (CRT) has a proven role in improving mortality in patients with heart failure and ventricular dyssynchrony. However, the effects of biventricular pacing (CRT) on ventricular arrhythmia susceptibility have not been definitely established, and data regarding the risk of ventricular arrhythmias (VA) with CRT has been limited and conflicting.The aim of this study was to compare the burden of VA in the short term before and after an upgrade to a cardiac resynchronization device in order to avoid the long term effects of myocardial remodeling.Methods: We analyzed 44 consecutive patients with severe LV systolic dysfunction who underwent an upgrade from a single chamber defibrillator to biventricular defibrillator due to worsening heart failure status.Results: CRT was associated with a decrease in VA in patients with high arrhythmic burden, in women and in patients older than 65.Conclusion: In this study we provide convincing evidence that in patients with identical electrophysiological substrate, biventricular pacing alone is associated with a decrease in VA burden.