Biventricular pacing in atrioventricular block with heart failure: Is pacing the left ventricle the right thing to do?

摘要

Background: Atrioventricular (AV) block is a common cardiac rhythm disorder treated with cardiac pacing, usually right ventricular (RV) apical pacing. High percentages of RV pacing are associated with long-term deleterious effects and may worsen left ventricular (LV) systolic function in patients with systolic heart failure. We evaluated the benefit of biventricular (BiV) pacing in patients with systolic dysfunction and AV block requiring pacing. Methods: Patients who had AV block with indications for pacing and LV systolic dysfunction having LV ejection fraction (LVEF) < 50% with New York Heart Association (NYHA) Class I, II or III symptoms were enrolled. All patients received a cardiac resynchronization device (pacemaker or implantable cardioverter defibrillator (ICD), the latter if they independently met an indication for defibrillator therapy). They were randomly assigned to RV pacing versus BiV pacing. The primary endpoint was a composite of all-cause mortality, a heart failure (HF) urgent care visit requiring intravenous therapy or a 15% or more increase in LV end-systolic volume index (LVESVI) Results: A total of 691 patients were randomized, and they were followed for an average of 37 months. The primary endpoint occurred in 190 patients (55.6%) in the RV pacing group and in 160 patients (45.8%) in the BiV pacing group (hazard ratio 0.74; 95% credible interval (CI) 0.60-0.90). The secondary end point of all-cause mortality or HF hospitalization was seen in 129 patients (37.7%) in the RV pacing group and 115 patients (32.9%) in the BiV group (hazard ratio 0.78; 95% credible interval (CI) 0.61-0.99). There was no significant difference in all-cause mortality alone. Procedure or systems-related complications were seen in 10.3% of patients. Conclusions: BiV pacing was superior to standard RV pacing in patients with AV block and LV systolic dysfunction with NYHA class I, II or III symptoms.