Left ventricular diastolic function in young long-term type 1 (insulin-dependent) diabetic men during exercise assessed by digitized echocardiography

Digitized M-mode echocardiograms were obtained during semisupinebicycle exercise in 10 relatively young (< 40 years) long-term( 12 years) type 1 (insulin-dependent) diabetic men, withoutovert heart disease, and 10 controls. Recordings were done atrest and during workloads of 50 and 100 W. At rest, heart ratewas similar in the groups, while at peak exercise it was higherin the diabetics whose left ventricular (LV) end-diastolic dimensionwas smaller at all study phases. From baseline to peak exercisethe diastolic period decreased in both groups, while the LVdiastolic peak rate of dimension increase, normalized for end-diastolicdimension, the rapid filling period and the LV dimension changeduring this period increased. The normalized peak rates of dimensionincrease and heart rates correlated positively in the groups.However, diabetics had a lower normalized peak rate of dimensionincrease after adjusting for heart rate by covariance analysis,both at rest (18%) and during peak exercise (20%). Thus, comparedto controls, this well defined group of type 1 diabetic menhad a consistent subclinical decrease in their peak rate ofdimension increase, both at rest and during exercise. Furthermore,the peak rate of dimension increase remained lower in the diabeticsubjects after normalization for their smaller end-diastolicdimension and after adjustment for their higher heart rate.