Cardiac function during stress testing in long-standing insulin-dependent diabetics.

Four dynamic tests of cardiac function were compared in a group of 13 long-standing insulin-dependent diabetics who had no clinical evidence of cardio-respiratory disease. One patient developed abnormal features during 24 hour ambulatory electrocardiograms while all 13 patients had normal exercise electrocardiograms. The change in left ventricular ejection fraction during dynamic supine exercise as measured by gated blood-pool scintigraphy was not significantly different from control subjects (p less than 0.1) while during cold stimulation testing the change in left ventricular ejection fraction in the diabetics was highly significantly different from the control subjects (p less than 0.01). Five of the patients had one or more abnormal tests of autonomic function. The cold stimulation test may be a sensitive index of cardiac dysfunction in diabetics but as the mechanism is unclear alternative explanations are possible. While the etiology of heart disease in such patients is uncertain it is likely to be multifactorial and this test may prove useful in investigating the natural history and pathogenesis of cardiac disease in diabetics.