糖尿病患者におけるSilent myocardial ischemia—トレッドミル運動負荷試験による検討

Silent myocardial ischemia in diabetics:by treadmill exercise testing

　今回我々は，糖尿病患者におけるsilent myocardial ischemiaをトレッドミル運動負荷試験を用いて検討した。対象は狭心症状のない糖尿病患者92例（男性28例，女性64例）で平均年齢は59±11歳であった。方法は，symptom-limitedのトレッドミル運動負荷試験を行い，負荷時または負荷直後の心電図でJ点より80msecにて0.1mV以上のST下降のあるものを陽性，max HRがtarget HRの80％以上で，かつ有意のST下降のないものを陰性，有意のST下降はないがmax HRがtarget HRの80％未満のものを判定不能とした。その結果，92例中21例（23％）が陽性，35例（38％）が陰性，36例（39％）が判定不能であった。判定不能例を除いた56例中では38％が陽性であった。トレッドミル陽性例と陰性例の臨床的特徴を比較したところ，陽性例では喫煙率，高血圧合併率，中性脂肪の値が有意に高かった。陽性例のうち冠動脈造影の施行された6例中4例に75％以上の有意狭窄が認められた。

We examined silent myocardial ischemia in diabe-tics 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 im-mediately after exercise for judgement. ST segment depression was defined as positive if there was at least 0.1mV of ST depression 80ms 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 depres-sion 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 de-pression, 36 (39%) showed equivocal ST depression. In 56 diabetics exclusive of treadmill equivocal pa-tients, 38% of patients showed positive ST depres-sion. Treadmill positive diabetics had a significan-tly higher rate of smokers, patients with hyperten-sion, and a higher triglyceride level as compared with treadmill negative diabetics. Coronary arterio-graphy, which was performed in six treadmill posi-tive diabetics, revealed coronary stenosis of more than 75% in four patients.