Right ventricular pacing and the risk of heart failure in implantable cardioverter-defibrillator patients

BackgroundRight ventricular (RV) pacing in implantable cardioverter-defibrillator (ICD) patients may have detrimental effects on morbidity and mortality, in particular by inducing heart failure (HF).ObjectiveWe investigated whether RV pacing increases the risk of HF in an asymptomatic ICD population.MethodsWe evaluated all patients without symptomatic HF who received an ICD. The primary endpoint was the occurrence of HF, which was defined as new HF, hospitalization for HF, or death due to HF. The secondary endpoint was appropriate shocks.ResultsThe study population consisted of 456 patients with mean left ventricular ejection fraction (LVEF) 40% ± 13%. Mean follow-up was 31 ± 22 months. Because of the bimodal distribution of pacing, patients were divided into two groups: paced ≤50% (median 0%; n = 313) and paced >50% (median 96%; n = 143). HF occurred more often in the paced >50% group (20% versus 9%; P <.001). Multivariate analysis identified RV pacing >50% (adjusted hazard ratio [HR] 1.85; 95% confidence interval [CI] 1.08–3.15; P = .03), baseline LVEF <26% (adjusted HR 3.15; 95% CI 1.77–5.59; P <.001), angina pectoris, history of atrial fibrillation, and baseline diuretic use as independent predictors of HF. RV pacing caused more HF events in patients with LVEF <26% (n = 64; 55% of paced >50% patients versus 20% of paced ≤50% patients; P = .006). RV pacing >50% also independently predicted appropriate shocks (adjusted HR 1.50; 95% CI 1.02–2.20; P = .04).ConclusionRV pacing was associated with an increased risk of HF in asymptomatic ICD patients, particularly in those with preexistent left ventricular dysfunction.