[Myocardial involvement in diabetic patients evaluated by exercise thallium-201 scintigraphy and cardiac...

To evaluate myocardial involvement in diabetes mellitus, we studied 39 patients with negative double-Master's test and without hypertension by exercise thallium-201 (T1-201) myocardial scintigraphy using a bicycle ergometer. Among the 39 patients, 12 (30.8%) showed filling defects in the scintigrams (positive cases), including eight with stress-induced defects and four with fixed defects. The positive cases had higher scores of diabetic complications (3.6 +/- 2.4 vs 2.1 +/- 1.8; p less than 0.05) and longer durations of diabetes as compared with those of the negative cases. The frequency of insulin therapy was also greater in the positive cases. Eleven patients (5 positive and 6 negative cases) who underwent cardiac catheterization had no significant stenotic lesions of their coronary arteries. However, all of the positive cases showed abnormal wall motion, mainly hypokinesis, by left ventriculography (LVG). The abnormalities of the LVG corresponded to the findings of the scintigrams (i.e. filling defects and decrease in washout ratios by circumferential profile analysis). These results suggest that in some diabetics myocardial involvement exists in the early stage without overt cardiac disease and exercise T1-201 scintigraphy is useful in detecting pre-clinical cardiomyopathy. Cardiomyopathy in diabetics seems to be due to disturbances of the myocardial microcirculation.