Prognostic significance of atrial fibrillation is a function of left ventricular ejection fraction

BACKGROUND: Atrial fibrillation (AF) has been reported to be associated with decreased survival in population-based studies. Its prognostic importance in end-stage heart failure is not clear. METHODS AND RESULTS: We investigated the prognostic implications of AF as function of left ventricular (LV) ejection fraction (EF) in 8,931 consecutive patients undergoing echocardiography at our medical center between 1990 and 1999. Patient characteristics were: age 66 +/- 13 years, EF 51 +/- 15, AF in 1,203 patients. There were 1,911 deaths over a mean follow up of 913 days. The prevalence of AF was 11% in patients with normal left ventricular ejection fraction (LVEF) (EF >/= 55%, n = 5, 130), and 18% each in those with mild (EF 41-54%, n = 1209), moderate (EF 26-40%, n = 1183) and severe reductions in left ventricular ejection fraction (LVEF) (EF /= 450, raising a possibility of enhanced susceptibility of these patients. CONCLUSIONS: The effect of AF on mortality diminishes with worsening LV function and is absent in those with severe LV dysfunction. Susceptibility of patients with QT prolongation to AF mortality warrants further attention.