Silent myocardial ischemia in unstable angina and acute myocardial infarction. Prospective clinical study

To establish the prevalence and characteristics of silent myocardial ischemia in patients with unstable angina and acute myocardial infarction and its possible correlation with coronary artery lesions; two groups patients were studied, fifteen with unstable angina and fifteen with acute myocardial infarction. In all patients a continuous 24 hours ECG recording was made with a solid state microprocessor for ST variation analysis, and all underwent coronary arteriography and ventriculography, the severity of coronary heart disease was determined by Gensini scoring system and the coronary angiography morphology was studied. In 86% patients with unstable angina ischemic ST changes were found, 90% of these episodes were silent. There were 66% of the patients with acute myocardial infarction and ST ischemic changes of these 75% were silent. There was no correlation with the ischemic myocardium score index, nor with the angiographic morphology or the heart rate. Therefore it can be said that myocardial ischemia is a result not only of anatomic factors but of many others such as vasoconstriction, endothelial, myocardial, systemic and hemorheological alterations.