Abstract 13023: Characteristics of Treatment Failure With Rate and Rhythm Control Strategies in Patients With Atrial Fibrillation: Insights From the AFFIRM (Atrial Fibrillation Follow-up Investigation of Rhythm Management) Trial

Introduction: In patients with atrial fibrillation (AF) both “rate control” and “rhythm control” therapies have distinct set of limitations. We sought to investigate the rates and reasons of crossover from an initially assigned rate control arm to rhythm control and from rhythm to rate control therapy in patients who were enrolled in the AFFIRM trial. Methods: We compared the characteristics of patients who continued in the initially assigned treatment arm versus those who crossed over to the alternative treatment strategy in both “rhythm” and “rate” control arms. Two-sample t-test and chi-squared tests were used to compare means and proportions respectively. Results: A total of 4,060 patients were enrolled in the AFFIRM trial and over a mean follow-up duration of 3.5 years, 842 of them underwent crossover from an initially assigned treatment arm. The rate of crossover from an initially assigned rhythm control arm (594/2033, 29.2%) was more frequent than the rate of crossover from rate control to rhythm control (248/2027, 12.2%, p < 0.0001). In the rhythm control arm, the patients who crossed over to rate control had a significantly higher incidence of prior failure of an antiarrhythmic drug (139/594, 23.4%) than in those who continued as assigned (210/1439, 14.6%, p < 0.0001). In the rate control arm, patients who crossed over to rhythm control were relatively younger (68.3 ± 8.2 vs. 69.7 ± 8.0 years in those who continued, p = 0.01). The leading reasons for crossover to rate control were failure to achieve or maintain sinus rhythm (272/594, 45.8%) and intolerable adverse effects (122/594, 20.5%). In comparison, the major reasons for crossover to rhythm control were failure to control AF symptoms (159/248, 64.1%) and intolerable adverse effects (9/248, 3.6%). The difference in crossover pattern was statistically significant (p < 0.0001). Conclusions: Rhythm control was abandoned more commonly than rate control in patients who were enrolled in the AFFIRM trial. Failure of antiarrhythmic drug therapy prior to randomization was a significant factor for crossover from rhythm to rate control. Patients who crossed over from rate to rhythm control were younger than those who continued. The crossover from rhythm to rate control was driven by the occurrence of adverse effects.