Objective: This study undertook to determine if the presence of atrial fibrillation in patients with asymptomatic and symptomatic left ventricular dysfunction was associated with increased mortality and, if so, whether the increase could be attributed to progressive heart failure or arrhythmic death.
Background: Atrial fibrillation is a common condition in heart failure with the potential to impact hemodynamics and progression of left ventricular systolic dysfunction as well as the electrophysiologic substrate for arrhythmias. The available data do not conclusively define the effect of atrial fibrillation on prognosis in heart failure.
Methods: A retrospective analysis of the Studies of Left Ventricular Dysfunction Prevention and Treatment Trials was conducted that compared patients with atrial fibrillation to those in sinus rhythm at baseline for the risk of all-cause mortality, progressive pump-failure death and arrhythmic death.
Results: The patients with atrial fibrillation at baseline, compared to those in sinus rhythm, had greater all-cause mortality (34% vs. 23%, p < 0.001), death attributed to pump-failure (16.7% vs. 9.4%, p < 0.001) and were more likely to reach the composite end point of death or hospitalization for heart failure (45% vs. 33%, p < 0.001), but there was no significant difference between the groups in arrhythmic deaths. After multivariate analysis, atrial fibrillation remained significantly associated with all-cause mortality (relative risk [RR] 1.34, 95% confidence interval [CI] 1.12 to 1.62, p=0.002), progressive pump-failure death (RR 1.42, 95% CI 1.09 to 1.85, p=0.01), the composite end point of death or hospitalization for heart failure (RR 1.26, 95% CI 1.03 to 1.42, p=0.02), but not arrhythmic death (RR 1.13; 95% CI 0.75 to 1.71; p=0.55).
Conclusions: The presence of atrial fibrillation in patients with asymptomatic and symptomatic left ventricular systolic dysfunction is associated with an increased risk for all-cause mortality, largely explained by an increased risk for pump-failure death. These data suggest that atrial fibrillation is associated with progression of left ventricular systolic dysfunction.