Structural conditions in the hypertrophied and failing heart

Abstract

Hypertrophy represents a chronic adaptation of the myocardium to diastolic (volume) or systolic (pressure) loads. Resultant “eccentric” and “concentric” hypertrophy is discussed relative to ventricular compliance. The need for defined pressure-volume curves with known ventricular mass and shape in human disease is stressed. Ultrastructural constraints to normal and abnormal function are noted in terms of the sarcomere, and the physiologic features of fiber orientation in the ventricular wall and their implications for normal function are denoted. In the absence of significant qualitative changes in structure in ventricular hypertrophy, the quantitative implications of these changes are noted. As yet, little is known of the fiber orientation and connective tissue skeleton of the heart in either severe hypertrophy or severe myocardial failure with dilatation.