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

BACKGROUND

Right ventricular (RV) pacing in implantable cardioverter-defibrillator (ICD) patients may have detrimental effects on morbidity and mortality, in particular by inducing heart failure (HF).

OBJECTIVE

We investigated whether RV pacing increases the risk of HF in an asymptomatic ICD population.

METHODS

We 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.

RESULTS

The 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 <or=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 <or=50% patients; P = .006). RV pacing >50% also independently predicted appropriate shocks (adjusted HR 1.50; 95% CI 1.02-2.20; P = .04).

CONCLUSION

RV pacing was associated with an increased risk of HF in asymptomatic ICD patients, particularly in those with preexistent left ventricular dysfunction.