Right ventricular pacing is associated with increased rates of appropriate implantable cardioverter defibrillator shocks

BACKGROUND: Right ventricular (RV) pacing has been associated with increased risk of pacemaker-induced cardiomyopathy, hospitalization and death among patients with implantable cardioverter defibrillators (ICDs). Little is known about its association with ventricular tachyarrhythmias. We hypothesize that RV pacing is associated with increased incidence of appropriate ICD shocks and death. METHODS: Retrospective study of consecutive patients with de novo ICD insertion (excluding cardiac resynchronization therapy devices) from a single tertiary care center. Patients were classified into <10% RV pacing (low-pace group) and ≥10% RV pacing (high-pace group). Data were compared using two-tailed t tests and Fisher's exact test. Binomial logistic regression was performed to identify predictors of appropriate ICD therapies. RESULTS: A total of 178 patients (54 high paced and 124 low paced) were included. Mean follow-up was 43 ± 11 months. Appropriate shocks occurred in 27 patients (15%) and were significantly higher in the high-pace group (35% vs. 10%, p = 0.008), as the number of deaths (31% vs. 11%, p = 0.001). Binary logistic regression showed a significantly increased risk of shock (OR 2.99, p = 0.01) and death (OR 3.61, p = 0.002) in high-paced patients. Multivariable analysis showed no difference in risk of shocks based on age, sex or ejection fraction. Older patients had higher risk of death. CONCLUSIONS: In this population of ICD patients, those with a high prevalence of RV pacing experienced more shocks for VF/VT and had higher mortality. Further studies should be done to determine whether minimizing RV pacing reduces arrhythmias, shock burden and death in patients with ICDs.