Comparison of Rate Versus Rhythm Control for Atrial Fibrillation in Patients With Left Ventricular Dysfunction (from the AFFIRM Study)

Optimal treatment for patients with atrial fibrillation (AF) and left ventricular (LV) dysfunction is not well defined. It is unclear if sinus rhythm is of greater benefit in patients with significantly reduced ejection fraction (EF) than in patients with normal or mildly depressed LV function. The Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study compared 2 treatment strategies: “rhythm control,” attempting to maintain sinus rhythm, principally with antiarrhythmic drugs, and “rate control,” allowing AF to persist or recur while controlling the ventricular rate. We sought to determine if rhythm control was superior to rate control for patients in the AFFIRM study with various degrees of LV dysfunction. The present study analyzed outcome data of 3,032 subjects from the AFFIRM study with LV dysfunction by 3 EF strata: 40% to 49%, 30% to 39%, and <30%. The end points were mortality, hospitalization, and a change in New York Heart Association (NYHA) class. Analyses were done by intent to treat and by final rhythm status. In conclusion, there was no significant improvement in mortality, hospitalization, and NYHA class with the strategy of rhythm control in any of the 3 EF strata. When the data were analyzed by final rhythm status, we again found no significant benefit to patients in the rhythm control arm.