Epidemiology of silent myocardial ischemia in asymptomatic middle-aged men (the ECCIS Project)

Abstract

To evaluate the prevalence of type I silent myocardial ischemia and silent myocardial infarction, 4,842 men aged 40 to 59 years, identified in occupational samples in Florence and Rome, and free from major heart disease, severe illnesses and chest pain, underwent a 3-stage diagnostic procedure. The first stage included resting electrocardiogram, hyperventilation test, exercise electrocardiogram and 24-hour Holter electrocardiogram. The subjects who were suspected of having type 1 silent myocardial ischemia or previous silent infarction at the first stage (n = 439; 9.1%) were entered into the second stage, which included echocardiogram, thallium 201 sintigraphy in conjunction with exercise testing or dipyridamole test, exercise radionuclide ventriculography and ergonovine test. Three hundred eighty-seven men participated in the second stage; after the diagnostic procedures were performed, 104 men (2.1%) were still suspected of having type 1 silent myocardial ischemia or infarction on the basis of predefined criteria. Sixty-two men continued on into the third diagnostic workup including coronary angiography. The final diagnosis of type 1 silent myocardial ischemia or infarction was reached in 25 patients (prevalence 0.52%; adjusted estimate 0.89%). Of these 25, 19 had coronary atherosclerotic disease, 1 had Kawasaki disease, 1 had coronary anomaly, 1 had induced focal coronary spasm, and 2 had normal coronary arteriograms despite the presence of unquestionable old myocardial infarction. Altogether, 6 patients with silent myocardial infarction were identified. The coronary profile, based on the measurement of a number of coronary risk factors, was definitely worse in the 25 subjects with type 1 silent myocardial ischemia or previous silent infarction than in the other subjects.