Abstract 4192: Unrecognized Myocardial Infarctions are Common in Cardiac Asymptomatic Subjects at High Vascular Risk

Abstract

Unrecognized myocardial infarction (UMI), generally assessed by the presence of a Q-wave on the electrocardiogram, is commonly found. Furthermore, mortality associated with UMI appears to be similar as for recognized myocardial infarction. With delayed enhancement cardiac MRI (DE-CMR) both Q-wave and non-Q wave infarctions can be identified. The aim of this study was to investigate the prevalence and determinants of UMI in high risk subjects without symptomatic coronary artery disease using DE-CMR. A DE-CMR was performed in 502 subjects with clinically manifest non-coronary atherosclerotic disease or marked risk factors for atherosclerosis. As all subjects had no known history of coronary artery disease, subendocardial and transmural scar tissue on DE-CMR was considered an UMI. In all subjects information on atherosclerotic risk factors was collected. Multivariable logistic regression was used to study the relation of risk factors with UMI. DE-CMR was of sufficient image quality in 480 (95.6%) subjects. Interobserver agreement was excellent (weighted kappa = 95%). An UMI was present in 45 (9.4%) of all subjects, and in 38 (13.1%) of 291 men and in 7 (3.7%) of 189 women. The risk of UMI increased from 6.0% (95%CI 2.2 – 9.8%) in those with two risk factors up to 26.2% (95%CI 15.2 – 37.3%) in those with 4 or 5 risk factors (male gender, age above mean of 53 years, ever smoking, history of stroke, and history of aneurysm of the abdominal aorta (AAA)). In multivariable analysis the risk of UMI was related to male gender (OR 2.6 (95%CI 1.1– 6.3)), age (OR 1.0 (95%CI 1.0 –1.1) per year), ever smoking (OR 3.1 (95%CI 1.0 –9.0), history of stroke (OR 2.1 (95%CI 1.0 – 4.4)) and history of AAA (OR 2.3 (95%CI 0.9 –5.9)). In high risk cardiac asymptomatic subjects UMI is common. The risk of UMI increases with increasing presence of risk factors.