Improvement of left atrial function is associated with lower incidence of atrial fibrillation and mortality after cardiac resynchronization therapy

Abstract

Left atrial (LA) volume is a predictor of cardiovascular events in patients with heart failure. Improvement of LA function and reverse remodeling was observed after cardiac resynchronization therapy (CRT). The purpose of this study was to explore the clinical significance of improvement in LA function after CRT. Echocardiographic studies were performed before and 3 months after CRT in 97 patients (72 men and 25 women; age 63.8 +/- 13.3 years) with standard CRT indication but no history of atrial fibrillation (AF). LA active emptying fraction based on the change in volumes (LAV-EF) were calculated, and significant improvement in LA function (LA responder) was defined as a relative increase >/=50% from baseline LAV-EF. The primary end-points were newly developed AF detected by ECG or device and all-cause mortality. After 1,200 +/- 705 days of follow-up, LA responders (n = 47 [48.5%]) had a significantly lower incidence of AF (12.8% vs 40%, P = .002) and mortality (17% vs 44%, P = .004) than did LA nonresponders. In Cox proportional hazard analysis, LA responders was the only independent predictor of lower risk of new-onset AF (hazard ratio 0.22, 95% confidence interval 0.08-0.61, P = .003), whereas both LA responders (hazard ratio 0.22, 95% confidence interval 0.09-0.53, P <.001) and left ventricular reverse remodeling (>10% reduction in left ventricular end-systolic volume at 3 months; hazard ratio 0.96, 95% confidence interval 0.93-0.99, P = .03) were independent predictors of lower risk of death after CRT. Improvement of LA function after CRT was associated with a lower incidence of AF and mortality in AF naïve patients with severe heart failure.