Diabetic myocardial alterations in ultrastructure and function.

Myocardial samples taken from six healthy and six alloxan-diabetic dogs by means of percutaneous needle-biopsy were investigated electronmicroscopically. Specific increase in the number of collagen fibers and that of mitochondria were demonstrated beside the widening of Z bands. In the same experimental animals, a close, inverse correlation was detected (y = 0.0068x + 0.1680; r = 0.8648; F = 29.6705; n = 12) between the values of the left ventricular passive elastic modulus and those of the plasma glucose disappearance rate determined immediately before the haemodynamic investigation. On the basis of the ultrastructural findings, the proliferation of collagen fibers can be made also responsible for functional disorder of the diabetic myocardium.