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

Abstract

Digitized M-mode echocardiograms were obtained during semisupine bicycle exercise in 10 relatively young (< 40 years) long-term (≥ 12 years) type 1 (insulin-dependent) diabetic men, without overt heart disease, and 10 controls. Recordings were done at rest and during workloads of 50 and 100 W. At rest, heart rate was similar in the groups, while at peak exercise it was higher in the diabetics whose left ventricular (LV) end-diastolic dimension was smaller at all study phases. From baseline to peak exercise the diastolic period decreased in both groups, while the LV diastolic peak rate of dimension increase, normalized for end-diastolic dimension, the rapid filling period and the LV dimension change during this period increased. The normalized peak rates of dimension increase and heart rates correlated positively in the groups. However, diabetics had a lower normalized peak rate of dimension increase after adjusting for heart rate by covariance analysis, both at rest (18%) and during peak exercise (20%). Thus, compared to controls, this well defined group of type 1 diabetic men had a consistent subclinical decrease in their peak rate of dimension increase, both at rest and during exercise. Furthermore, the peak rate of dimension increase remained lower in the diabetic subjects after normalization for their smaller end-diastolic dimension and after adjustment for their higher heart rate.

Left ventricular diastolic function, type 1 diabetes mellitus, exercise, digitized echocardiography