Clinical and Echocardiographic Factors Associated With New-Onset Atrial Fibrillation in Heart Failure　- Subanalysis of the WARCEF Trial.

Background: Heart failure (HF) patients have a high incidence of new-onset AF. Given the adverse prognostic influence of AF in HF, identifying patients at high risk of developing AF is important. Methods and Results: The incidence and factors associated with new-onset AF were investigated in patients in sinus rhythm with reduced LVEF enrolled in the Warfarin versus Aspirin in Reduced Cardiac Ejection Fraction (WARCEF) trial. Analyses involved clinical factors alone (n=2,219), and clinical plus echocardiographic findings (n=1,125). During 3.5+/-1.8 years of follow-up, 212 patients (9.6% of total cohort) developed AF. In both samples, new-onset AF was associated with age, male sex, White race, and IHD. Among echocardiographic variables, only LAD predicted AF. On multivariate Cox modeling, age (HR, 1.02; 95% CI: 1.00-1.03, P=0.008), IHD (HR, 1.37; 95% CI: 1.02-1.84, P=0.036) and LAD (HR, 1.48; 95% CI: 1.15-1.91, P=0.003) remained associated with AF onset. Patients with IHD, LAD>4.5 cm and age>50 years had a 2.5-fold higher risk of AF than patients without any of these characteristics (HR, 2.52; 95% CI: 1.72-3.69, P<0.0001). Conclusions: Age, IHD and LAD independently predict new-onset AF in HF patients in sinus rhythm, at younger age and smaller LAD than generally believed. This information may be useful to risk-stratify HF patients for AF development, allowing close monitoring and possibly early detection.