Abstract 2934: Prolonged QRS Duration is Associated with a Marked Increase in Mortality in the AF-CHF Study
Prolonged QRS duration (QRSd) has been associated with increased mortality in many studies of patients with left ventricular (LV) dysfunction. However, not all studies show a clear relation between QRS duration and outcomes. Understanding the relative and absolute risks of death with normal vs. abnormal (≥120 msec) QRSd may be useful in understanding the potential absolute benefits of interventions such as the implantable defibrillator. The Atrial Fibrillation and Congestive Heart Failure (AF-CHF) study was a randomized trial of rhythm control vs. rate control in 1376 patients with atrial fibrillation and ejection fraction (EF) ≤ 35%, and heart failure (NYHA class II-IV or [EF < 25% or prior CHF hospitalization]). The primary result showed no mortality difference between treatment strategies over 37 ± 19 months of follow-up. Overall, mean actuarial annual cardiovascular mortality was 7.8%, with a hazard ratio of 1.058 (rhythm vs rate). In this substudy, 1219 patients had QRS duration (< 120 ms or ≥ 120 ms) and EF < 30% or ≥ 30% available at baseline ; 81.7% were male, age 66.7± 11.1 years, 31.3% class III-IV at baseline, mean EF 26.9 ± 6.0 % ; 47.8% had coronary artery disease (CAD). In a multivariable analysis adjusting for treatment, age, sex, NHYA Class at baseline (3– 4 vs 1–2), EF, and diagnosis (CAD yes vs no), QRS ≥ 120 ms was associated with a HR for CV death of 1.8 [95% CI(1.4, 2.3)], all cause death of 1.7 [95% CI(1.4, 2.1)] and arrhythmic death of 2.3 [95% CI(1.6, 3.3)], p< 0.0001. Age HR 1.02 [95% CI(1.01, 1.03)], NYHA HR 1.36 [95% CI(1.1, 1.7)], QRS duration ≥ 120 HR 1.8 [95% CI(1.4, 2.3)] and CAD if yes HR 1.7, (CI 1.4–2.2), were the independent predictors of CV death. In patients with AF and CHF, a prolonged QRS duration (≥ 120 ms) is associated with a substantial increase in cardiovascular mortality, all cause death and arrhythmic death, independently of EF or underlying disease.