Exercise capacity and cardiac function in type 1 diabetic patients treated with continuous subcutaneous insulin infusion. A controlled study

Abstract

In order to investigate the effect of improved glycaemic control on exercise capacity and cardiac function, bicycle exercise and echocardiography at rest and after exercise was performed in 24 short-term type 1 diabetic patients, randomized to conventional insulin therapy (CIT) or to continuous subcutaneous insulin infusion (CSII). After 6 months significant improvement in glycaemic control was seen in the CSII group showing a decrease in mean blood glucose and haemoglobin Ale (HbAlc), while no change was observed in the CIT group. Exercise capacity increased by 24% (p<0.01) in the CSII group and decreased by 16% (NS) in the CIT group. In the CSII group fractional shortening of the left ventricle during rest decreased by 14% (p<0.02), while an increase of 2% (NS) was seen in the CIT group. Further, changes of left ventricular fractional shortening during rest were inversely correlated to changes in exercise capacity. After exercise, fractional shortening of the left ventricle and rate-pressure product was unchanged in the two groups. In conclusion this study shows a beneficial effect of improved glycaemic control induced by CSII on exercise capacity possibly by reducing resting state demands to the cardiovascular system.

Key Words:

• cardiac function
• echocardiography
• exercise capacity
• metabolic control
• type 1 diabetes