0482: Silent AF in acute myocardial infarction severely impairs long term prognosis

BackgroundSilent Atrial Fibrillation (AF) has recently been shown to be common in acute myocardial infarction (AMI) and to dramatically increase in-hospital death. However, the long term prognosis of silent AF in AMI remains unknown.MethodsFrom the 1st May 2011 and the 31st January 2013 all the consecutive patients were prospectively analyzed by continuous ECG monitoring (CEM) during the first 48 hours after admission for an AMI. Silent AF was defined as asymptomatic episodes lasting at least 30 sec. Patients discharged alive and with a follow-up at 1 year were included in the present study. Patients who developed silent AF were compared with symptomatic AF and No AF group.ResultsAmong the 737 patients included, 96 (13.0%) developed silent AF and 56 (7.6%) developed symptomatic AF during their hospital stay. Compared with the no AF group, patients with silent AF were markedly older 80 (64-84) vs. 61 (53-75) years; p<0.001), more frequently women (42% vs. 30%); p=0.069), and less frequently smoker (24% vs. 37%; p<0.001).GRACE risk score was significantly higher in silent AF group (131(101-148)) than in no AF group (98(75-); p<0.001). They also had a significant left atrial (LA) enlargement with LA surface indexed at 10.1 (8.5-12.6) vs. 9.2 (7.4-10.9)cm²/ m²; p<0.001 and LA volume indexed 29.4 (21.0-43.1) vs. 24.1 (18.1-32.9)cm3/m²; p<0.001. At one year follow-up, rehospitalizations for heart failure were more frequent after silent AF (4.2%) or symptomatic AF (8.9%) than in no AF group (1.4%), (p<0.001). One year mortality was dramatically higher in silent AF group (9.4%) and in symptomatic AF group (17.9%) than in no AF group (3.8%) (p