Collagen in naturally occurring hypertrophied porcine myocardium.

A comparison of the collagen network in three dimensions was conducted in 8 hypertrophic cardiomyopathy (HCM)-affected and 8 normal hearts. All these hearts were obtained from male and age-matched pigs of the same breeding farm under identical feeding conditions. The selection of HCM-affected heart was based on the abnormal histologic features such as marked disorientation of muscle cells, thickening of the intramural coronary arterial wall with a narrowed lumen, endocardial fibrosis, and myocardial fibrosis. Mean values of heart weight and ratio of heart to body weight of HCM group were significantly (p < 0.01) increased by 36% and 47%, respectively, but not the body weight, as compared to those of the normal group. The scanning electron microscopic (SEM) investigation demonstrated that collagen weave, struts, and strands appeared more numerous in HCM-affected myocardium than in normals. Moreover, the tendons of collagen in HCM-affected myocardium showed increases in both numbers and thickness.