Three-dimensional characteristics of the intramyocardial microvasculature of hypertrophied human hearts.

The three-dimensional architecture of the intramyocardial microvasculature was demonstrated in hypertrophied human hearts using Evan's method: scanning electron microscopic observation of the cardiac muscle chemically digested by hydrochloric acid and collagenase. Twenty autopsied hearts, which had already been fixed in 10% formalin, were investigated, including 17 hypertrophied hearts (mean cardiac weight, 587 g) and three control hearts (mean cardiac weight, 238 g). The luminal surfaces of the arterioles were characterized by the coiled arrangement of their smooth muscle cells. The structure of these vessels was not significantly different in hypertrophied and normal hearts. The capillaries showed great changes in the hypertrophied muscle: capillaries running on the body of the myofibres, in loop form on disorganized myofibres, and protruding into myofibres and/or probably penetrating through them. These features indicated an increase in the ratio of capillary/myofibre in hypertrophied human hearts. In hypertrophied hearts the venules had a more developed system than normal hearts, but without change in their basic architecture.