Acute infection is suspected of involvement in the onset of acute myocardial infarction (MI). We aimed to assess the incidence, pathogenesis and prognosis of post-infectious MI. All consecutive patients hospitalized for an acute MI in coronary care units were prospectively included. Post-infectious MI was defined by a concurrent diagnosis of acute infection at admission. Type 1 MI (acute plaque disruption) or Type 2 MI (imbalance in oxygen supply/demand) were adjudicated according to the universal definition of MI. From the 4573 patients admitted for acute MI, 466 (10%) had a concurrent acute infection (median age 78 (66-85) y, 60% male), of whom 313 (67%) had a respiratory tract infection. Type 2 MI was identified in 72% of post-infectious MI. Compared with other MI, post-infectious MI had a worse in-hospital outcome (11 vs. 6% mortality, p < 0.01), mostly from cardiovascular causes. After adjusting for confounders, acute infections were no more associated with mortality (odds ratio 0.72; 95% confidence interval 0.43-1.20). In the group of post-infectious MI, Type 1 MI and respiratory tract infection were associated with a worse prognosis (respective odds ratio 2.44; 95% confidence interval: 1.12-5.29, and 2.89; 1.19-6.99). In this large MI survey, post-infectious MI was common, accounting for 10% of all MI, and doubled in-hospital mortality. Respiratory tract infection and Type 1 post-infectious MI were associated with a worse prognosis.
Keywords: Type 2 myocardial infarction; acute coronary syndrome; elderly; in-hospital mortality; infection; pneumonia; pulmonary tract infection; sepsis.