Abstract
ObjectivesThe beneficial effects of cardiac resynchronization therapy (CRT) are thought to result from favorable left ventricular (LV) reverse remodeling, however CRT is only successful in about 70% of patients. Whether response to CRT is associated with a decrease in ventricular arrhythmias (VA) is still discussed controversially. Therefore, we investigated the incidence of VA in CRT responders in comparison with non-responders.MethodsIn this nonrandomized, two-center, observational study patients with moderate-to-severe heart failure, LV ejection fraction (LVEF) ≤35%, and QRS duration >120 ms undergoing CRT were included. After 6 months patients were classified as CRT responders or non-responders. Incidence of VA was compared between both groups by Kaplan-Meier analysis and Cox regression analysis. ROC analysis was performed to determine the aptitude of LVEF cut-off values to predict VA.ResultsIn total 126 consecutive patients (64±11years; 67%male) were included, 74 were classified as responders and 52 as non-responders. While the mean LVEF at baseline was comparable in both groups (25±7% vs. 24±8%; P = 0.4583) only the responder group showed an improvement of LVEF (36±6% vs. 24±7; p<0.0001) under CRT. In total in 56 patients VA were observed during a mean follow-up of 28±14 months, with CRT responders experiencing fewer VA than non-responders (35% vs. 58%, p<0.0061). Secondary preventive CRT implantation was associated with a higher likelihood of VA. As determined by ROC analysis an increase of LVEF by >7% was found to be a predictor of a significantly lower incidence of VA (AUC = 0.606).ConclusionsImprovement of left ventricular function under cardiac resynchronization therapy goes along with a reduced incidence of ventricular arrhythmia.
Highlights
Cardiac resynchronization therapy (CRT) has become an integral component of systolic heart failure (HF) therapy
A meta-analysis of large clinical trials, involving patients being implanted with CRT-devices with defibrillator backup (CRT-D), could not show a reduction in device interventions due to ventricular arrhythmias (VA) [8]
Besides reduction in left-ventricular end-systolic volume (LVESV), as the established marker for mechanical remodeling, improved left ventricular systolic function (LVEF) could be a functional and obtainable alternative, which might be less afflicted by inter- and intra-observer variability [16,17,18,19]
Summary
Cardiac resynchronization therapy (CRT) has become an integral component of systolic heart failure (HF) therapy. Up to date there is a bulk of evidence for the beneficial effect of CRT in patients with moderate-to-severe clinical impairment, which includes improved quality of life, fewer hospitalizations and decreased mortality [1]. In patients responding to CRT left-ventricular reverse remodeling leads to a reduction of myocardial stretch and favorable neurohumoral changes [10,11]. It can invoke profound changes on the (sub)cellular level [12,13]. Whether an improvement of LVEF among CRT patients goes along with a decreased incidence of VA has not been prospectively evaluated
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