[Asymptomatic ischemia following myocardial infarct]

To assess the incidence of silent ischemia after myocardial infarction, a prospective series of 100 consecutive patients was studied 5 weeks after the acute event. Objective evaluation of myocardial ischemia included a 9-lead ECG, thallium-201 scintigraphy and radionuclide ventriculography, each at rest and during symptom-limited bicycle ergometry. Diagnostic criteria were ECG: greater than or equal to 1 mm horizontal or downsloping ST depression or greater than or equal to 1 mm ST elevation; thallium scintigraphy: a clearly reversible perfusion defect at rest, detectable only after exercise; radionuclide ventriculography: an exercise-induced decrease in global LVEF greater than or equal to 5% and/or in anyone regional EF greater than or equal to 14%. Presence of ischemia was assumed if at least 2 of 3 objective ischemic signs were found. This was the case in 28 of 100 patients. During exercise, 15 of 100 patients complained of chest pain, but only 8 (54%) had objective evidence of ischemia. Thus, silent ischemia was demonstrated in 20 of 100 patients. The sensitivity of both nuclear cardiology procedures was markedly superior to that of the ECG in diagnosing post-myocardial ischemia.