Adverse effect of ventricular pacing on heart failure and atrial fibrillation among patients with normal baseline QRS duration in a clinical trial of pacemaker therapy for sinus node dysfunction

• Published in: Circulation (New York, N.Y.) N.Y.), 2003-06, Vol.107 (23), p.2932-2937
• Main Authors: SWEENEY, Michael O, HELLKAMP, Anne S, ELLENBOGEN, Kenneth A, GREENSPON, Arnold J, FREEDMAN, Roger A, LEE, Kerry L, LAMAS, Gervasio A
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Atrial Fibrillation - etiology; Biological and medical sciences; Bradycardia - complications; Bradycardia - therapy; Cardiac Pacing, Artificial - adverse effects; Cardiac Pacing, Artificial - methods; Cardiology. Vascular system; Electrocardiography; Female; Follow-Up Studies; Heart; Heart Failure - etiology; Heart failure, cardiogenic pulmonary edema, cardiac enlargement; Hospitalization - statistics & numerical data; Humans; Male; Medical sciences; Proportional Hazards Models; Randomized Controlled Trials as Topic - statistics & numerical data; Risk Assessment; Sick Sinus Syndrome - complications; Sick Sinus Syndrome - diagnosis; Sick Sinus Syndrome - therapy; Survival Analysis
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/01.CIR.0000072769.17295.B1

Dual-chamber (DDDR) pacing preserves AV synchrony and may reduce heart failure (HF) and atrial fibrillation (AF) compared with ventricular (VVIR) pacing in sinus node dysfunction (SND). However, DDDR pacing often results in prolonged QRS durations (QRSd) as the result of right ventricular stimulation, and ventricular desynchronization may result. The effect of pacing-induced ventricular desynchronization in patients with normal baseline QRSd is unknown. Baseline QRSd was obtained from 12-lead ECGs before pacemaker implantation in MOST, a 2010-patient, 6-year, randomized trial of DDDR versus VVIR pacing in SND. Cumulative percent ventricular paced (Cum%VP) was determined from stored pacemaker data. Baseline QRSd 40%) and VVIR (HR 2.56 [95% CI, 1.48 to 4.43] for Cum%VP >80%). The risk of AF increased linearly with Cum%VP from 0% to 85% in both groups (DDDR, HR 1.36 [95% CI, 1.09, 1.69]; VVIR, HR 1.21 [95% CI 1.02, 1.43], for each 25% increase in Cum%VP). Model results were unaffected by adjustment for known baseline predictors of HF hospitalization and AF. Ventricular desynchronization imposed by ventricular pacing even when AV synchrony is preserved increases the risk of HF hospitalization and AF in SND with normal baseline QRSd.