[Silent myocardial ischemia in diabetics--by treadmill exercise testing]

We examined silent myocardial ischemia in diabetics by treadmill exercise testing. There were 28 diabetic men and 64 diabetic woman without angina, with a mean age of 59 +/- 11 years. Symptom-limited treadmill exercise testing was performed, and we used the electrocardiogram during exercise and immediately after exercise for judgement. ST segment depression was defined as positive if there was at least 0.1 mV of ST depression 80 ms from the J point. It was defined as negative if max heart rate (HR) was more than 80% of target HR and there was no significant ST depression. It was defined as equivocal if there was no significant ST depression but max HR was less than 80% of target HR. In 92 diabetics, 21 patients (23%) showed positive ST depression, 35 (38%) showed negative ST depression, 36 (39%) showed equivocal ST depression. In 56 diabetics exclusive of treadmill equivocal patients, 38% of patients showed positive ST depression. Treadmill positive diabetics had a significantly higher rate of smokers, patients with hypertension, and a higher triglyceride level as compared with treadmill negative diabetics. Coronary arteriography, which was performed in six treadmill positive diabetics, revealed coronary stenosis of more than 75% in four patients.