High rate of recurrence at long-term follow-up after new-onset atrial fibrillation during acute myocardial infarction.

Aims: Silent and symptomatic atrial fibrillation (AF) are common during acute myocardial infarction (AMI), and associated with higher in-hospital and 1-year mortality. Are silent and symptomatic AF associated with higher rates of AF recurrence after hospitalization for AMI?

Methods And Results: All consecutive patients admitted for AMI between January 2012 and August 2015 were prospectively analysed by continuous electrocardiogram monitoring <48 h after admission. Silent AF was defined as asymptomatic episodes lasting at least 30 s. The population was divided into three groups: no-AF, silent AF, and symptomatic AF. Altogether, 1621 patients were included in the prospective study and discharged alive from hospital. After excluding those with previous AF, permanent AF since the AMI and coronary artery bypass grafting surgeries and those lost to follow-up, 1282 remained. During the AMI, 1058 patients (83%) had a persistent sinus rhythm (SR), 168 (13%) had silent AF, and 55 (4%) had symptomatic AF. After a median follow-up of 1037 days (interquartile range 583-1342), new AF episodes were recorded in 59 patients (6%) of the SR group, 21 (13%) in the silent AF group, and 13 (24%) in the symptomatic AF group (P < 0.001). After Cox multivariate analysis, AF during AMI, indexed left atrial volume, age, and creatinine at discharge were identified as independent risk factors of AF after AMI.

Conclusion: The results of our large-scale study suggest that patients experiencing paroxysmal new-onset AF (silent or symptomatic) during AMI are at higher risk of AF at follow-up. Our data raise the question of implementing anticoagulation therapy following these brief and often neglected episodes.