Abstract 17834: Incident Cardioversion is Associated with Reduced Mortality among Older Adults with Atrial Fibrillation: Insights from the AFFIRM Trial
Background: A rhythm control strategy has not been shown to improve long-term outcomes in atrial fibrillation (AF), possibly due to detrimental effects of antiarrhythmic medications. Aging is associated with impaired left ventricular early relaxation, thus, diastolic filling depends more on atrial contraction, impaired in AF. Electrical cardioversion (EC) is an alternate way to restore normal sinus rhythm, but is often underused in older adults due to concern for its invasive nature and risk of stroke, and lack of evidence for long-term benefit. We explored the hypothesis that the use of EC would be associated with reduced mortality in older adults with AF.
Methods: In the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) trial, 4060 patients with AF were randomized to rate versus rhythm control strategy. Of these, 3091 (76%) patients were ≥65 years. EC was a rhythm control strategy, and 47% of patients in the rhythm-control group received EC. However, 36% of the rate-control patients also received EC. We used multivariable Cox regression models, adjusting for baseline demographics and other covariates including randomization factor, to estimate the association between incident EC and outcomes during 6 years of follow-up.
Results: Patients (n=3091) had a mean (±SD) age of 73 (±4) years, 43% were women and 9% African American. EC was associated with significant reduction in all-cause mortality among elderly AF patients (adjusted HR when EC was compared with no-EC, 0.71; 95% CI, 0.58–0.87; p=0.001). In contrast, among younger adults, EC was not associated with mortality (adjusted HR when EC was compared with no-EC, 1.46; 95% CI, 0.89–2.39; p=0.138). This age-related difference in the association between EC and mortality was statistically significant (adjusted p for interaction, 0.016).
Conclusions: Older adults with AF receiving incident electrical cardioversion had lower risk of death. These findings are intriguing and mechanistically plausible, but need to be tested prospectively.
- © 2010 by American Heart Association, Inc.