糖尿病患者の運動負荷ベクトル心電図(Frank法)

The myocardial damage in diabetic patients was evaluated by both resting and exercise vectorcardiograms. Exercise vectorcardiograms were obtained in the supine position by a submaximal exercise test using a bicycle ergometer from 65 patients with diabetes mellitus, 10 with ischemic heart disease, 8 with essential hypertension and 20 normal controls. To investigate the cause of myocardial damage in diabetic patient, vectorcardiograms (VCG) of dogs which had been injected with allylamine intravenously, were recorded. The results were as follows: 1. QRS bites defined as deviation from a smooth conture of the VCG loop with a duration longer than 2 msec and an amplitude greater than 0.05 mv were observed more often in diabetic patients than in normal controls. 2. The prevalence of the QRS bite increased along with an increment in the duration of diabetes mellitus and in the frequency of diabetic microangiopathy of ocular fundus. 3. The magnitude of the QRS bite increased with exercise, both in diabetic patients with an abnormal resting ECG and in patients with a normal resting ECG and a vectorcardiographically abnormal response to the exercise. 4. Diabetic patients frequently showed ST,T changes in VCG after exercise regardless of the resting ECG. 5. Repeated intravenous injection of allylamine frequently caused QRS bite in the VCG of dog's. 6. Pathological studies on the myocardium of the dog showing bite in VCG revealed lesions characterized by subendotherial proliferation of mononuclear cells, mainly in small intramural coronary arteries 100-200μm in diameter. The results suggest that microangiopathy of the myocardium would be responsible for diabetic myocardial damage.