1978 Volume 42 Issue 8 Pages 955-960
The validity of isoproterenol test in the diagnosis of ischemic heart disease in the aged was evaluated in 67 autopsied cases. The additional ST segment depression of 0.5 mm or greater of the ischemic type after the intravenous infusion of isoproterenol (ISP) at a rate of 0.02 μg/kg/min for five minutes was considered to be the positive test. The sensitivity in 25 severe coronary stenoses of 75% or more was 72.0%, and specificity in 42 mild coronary stenoses was 71.4%. The false negative results were observed in 6 cases of ten myocardial infarctions, and the false positive results were observed in 5 cases of seven stenotic valvular diseases. The sensitivity and specificity after excluding the myocardial infarction and stenotic valvular disease were 100% and 81.8%, respectively. ST depression at rest was a poor indication of the coronary stenosis, and the specificity of the ISP test in the abnormal resting ST depression was 64.7%. The increases in heart rate and cardiac index after ISP infusion were greater in severe coronary stenosis without myocardial infarction than in mild coronary stenosis, indicating the hypersensitivity to the beta-adrenergic stimulation. The hemodynamic responses in myocardial infarction to the ISP infusion were similar to the reponses in mild coronary stenosis. The isoproterenol test was a safe and useful method not only in the assessment of the coronary heart disease, but also in clarifying the pathophysiological mechanism.
