Frequent episodes of silent myocardial ischemia after apparently uncomplicated myocardial infarction.

Frequent episodes of silent myocardial ischemia were documented in two patients, one with recognized and one with unrecognized prior myocardial infarction. Neither patient had symptoms after the infarction, but both demonstrated silent myocardial ischemia on exercise testing, which prompted further study with 48 hour ambulatory electrocardiographic (Holter) recordings. In each patient, heart rate recorded with the Holter monitor during the ischemic episodes was usually less than that observed during ischemia precipitated by exercise testing. This suggests that increased vasoconstrictive tone may play a role in silent ischemic episodes occurring during daily activities.