Atrial fibrillation during myocardial infarction with and without ST segment elevation

INTRODUCTION: The occurrence of atrial fibrillation (AF) in the acute phase of myocardial infarction with ST segment elevation is common and responsible for an excess hospital mortality. The aim of this work was to define the incidence, predictive factors, and the prognostic impact of AF during MI with and without raised ST segment in the RICO study. PATIENTS AND METHODS: Between January 2001 and July 2003, 1701 patients were included in this study: 130 (7.6%) had AF in the first 24 hours of management (AF+ group); 1571 (92.4%) remained in sinus rhythm (AF- group). RESULTS: Among the 1701 patients included in this study, 1197 (70.4%) had MI with raised ST and 504 (29.6%) had MI without raised ST. The incidence of AF was identical whatever the type of MI (7.6% with raised ST versus 7.7% without, p=0.334). The presence of Killip class >2 on admission and chronic obstructive pulmonary disease were independent predictive factors for the occurrence of AF (OR=3.84, p=0.007, and OR=2.47, p=0.014 respectively). The presence of AF was significantly associated with the occurrence of ventricular arrhythmia and/or cardiovascular mortality during admission in the non-selected MI population whatever the type of MI (raised ST ; AF+; 34% and AF-; 18%, p<0.01 versus without raised ST; AF+; 36% and AF-; 16%, p = 0.01). CONCLUSION: This study provides evidence that the incidence of AF during the first 24 hours of MI, as well as its poor prognosis, are identical whether or not there is ST segment elevation.