Assessment of myocardial perfusion during cold stress using thallium-201 scintigraphy in diabetic patients with abnormal changes in left ventricular function during cold stress.

Eleven type-I (insulin-dependent) diabetic patients with abnormal changes in left ventricular function in response to cold stress (CS) were investigated to try and determine the cause of these abnormal responses. Resting M-mode echocardiography demonstrated that all 11 patients had normal left ventricular dimensions and wall motion, thereby excluding overt cardiomyopathy. Thallium-201 scintigraphy was used to assess myocardial perfusion during CS and eight patients were found to have perfusion defects during stress which persisted in four. It is possible that CS unmasks evidence of myocardial ischemia but it is also possible that the abnormal responses to CS reflect altered vasomotor reactivity in the diabetic patient, producing coronary spasm. Left ventricular function may be influenced by many factors in diabetes and an abnormal CS test may not necessarily indicate structural disease. Such tests, however, may help in the further understanding of the pathophysiology of heart disease in diabetes.