Significance of recurrences of new atrial fibrillation in acute myocardial infarction.

Background: Although new-onset atrial fibrillation (AF) frequently recurs following the acute myocardial infarction, the significance of AF recurrences is unknown.

Objective: The objective of the present study was to evaluate the incidence, clinical predictors and prognostic significance of AF recurrences following the acute myocardial infarction.

Methods And Results: A total of 320 consecutive patients with AF following the acute myocardial infarction were evaluated and the patients with AF recurrences were compared to those with single episodes of AF in whom AF did not recur after restoration of sinus rhythm. The incidence of AF recurrences was 22.5%. AF recurrences were highly associated with congestive heart failure and worse Killip class was identified as the most important predictor of AF recurrences. Patients with AF recurrences had poorer outcome, including higher in-hospital (36.1% versus 12.9%) and 7-year (68.2% versus 48.6%) mortality. After multivariate adjustment, AF recurrence remained an independent predictor of in-hospital [odds ratio (OR) = 3.08, 95% confidence interval (CI), 1.45-6.53, p = 0.001], and 7-year [relative risk (RR) = 1.52, 95% CI, 1.00-2.31, p = 0.026] mortality.

Conclusion: New-onset AF frequently recurs following the acute myocardial infarction and our analysis demonstrated that recurrences of AF independently predicted in-hospital and long-term mortality.