Cardiac function and insulin-dependent diabetes: radionuclide ventriculography in young diabetics

We have compared left ventricular function in 40 insulin-dependent diabetic patients (30 male, 10 female) aged 16-30 years (mean 23 years) with duration of diabetes 3 months to 25 years (mean 10 years) with 19 healthy age and sex-matched controls using radionuclide ventriculography at rest, during cold-pressor stimulation, isometric exercise, and dynamic exercise. There were no differences in exercise or smoking habits in the two groups. All subjects had a normal resting electrocardiogram and a normal electrocardiographic response to dynamic exercise using the Bruce protocol on the Marquette Computer Assisted System of Exercise. Left ventricular ejection fraction was similar at rest and fell in diabetics and controls, respectively, by 2.3 +/- 1.0% and 3.0 +/- 0.08% (NS) and by 2.4 +/- 0.8% and 2.2 +/- 0.8% (NS) during isometric exercise, and cold pressor testing. During supine dynamic exercise on a bicycle ergometer ejection fraction rose in both groups by 13.9 +/- 1.7% and 13.7 +/- 1.6%, respectively (NS). No statistically significant differences were found in peak ventricular filling and emptying rates and abnormalities of regional wall motion did not develop. Two female patients with diabetes for more than 10 years had an abnormal response to dynamic exercise manifested by a fall in ejection fraction. In comparison to the higher frequency of abnormalities reported in diabetics using echocardiography and the measurement of systolic time intervals, abnormal left ventricular function assessed by radionuclide ventriculography is uncommon in young patients.