Silent ischemia a clinical update

18 Mar
2011

Silent ischemia

Case 1

A 49-year-old insurance executive was scheduled for an exercise tolerance test. The patient had no significant past medical history and was in excellent health. He jogged two miles regularly three times a week and played golf on weekends. Screening for hypercholesterolemia in the pre­ceding two years yielded values consistently under 200 mg/ dl. He had been a heavy cigarette smoker for over 20 years, but stopped in the preceding month. Physical examination of the heart and lungs was unremarkable.

Family history was remarkable for the sudden death of his father at age 47 and myocardial infarction in one brother at age 45. Routine electrocardiogram was within normal limits. The baseline blood pressure was 125-70 mm Hg and heart rate 68 beats/min. At 2 min 20 s in stage 2 of the Bruce protocol, electrocardiographic evidence of myocardial ische­mia was noted (2 mm horizontal ST depressions) in inferior and anterolateral precordial leads. The patient had no complaint and felt he could continue exercising, assessing the work load as “light.” Seconds later, his blood pressure dropped from 150/70 mm Hg to 100/60 mm Hg accompanied by greater depression of the ST segments in the precordial leads. The patient remained asymptomatic, but the physician elected to terminate the test. Maximum heart rate achieved was 115 beats/minute. The blood pressure returned to baseline two minutes into the recovery period; however, ischemic ST changes persisted for nine minutes and were accompanied by frequent premature beats. A thallium scintigram confirmed the presence of global ischemia and demonstrated a fixed defect in the inferior wall compatible with an old inferior wall myocardial infarction. cialis super active

Coronary angiograms revealed severe stenosis of the left main coronary artery, with good distal run off, and total occlusion of the right coronary artery. An area of akinesis was present in the inferior wall. Left ventricular ejection fraction was estimated to be 50 percent. Triple coronary artery bypass surgery was performed and recovery was uneventful. On follow-up six months later, he remained asymptomatic and was taking one aspirin daily.

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