The Finer Intramyocardial Vasculature in Various Forms of Experimental Cardiac Hypertrophy

The finer intramyocardial vascular architecture in various forms of cardiac hypertrophy was studied by a combined stereomicro‐angiographic and histological procedure. Significant cardiac hypertrophy was induced by renal hypertension, aortic stenosis and swimming exercise. The training‐induced hypertrophy was reversible. The myocardial vascular architecture was altered in cardiac hypertrophy. There were essential differences in the vascular patterns of training‐induced hypertrophy, on one hand, and hypertrophy secondary to hypertension and aortic stenosis, on the other. The nature of these differences suggested that training‐induced hypertrophy was associated with neoformation of vessels in an otherwise structurally unaltered myocardial vasculature, while the other forms of hypertrophy were dominated by a transformation of the preformed vascular pattern. In the regression of hypertrophy, which took place during the resting period after training, only minor changes appeared in the myocardial vascular pattern.