The relationship of left ventricular geometry and hypertrophy to left ventricular function in valvular heart disease.

Valvular heart disease imposes a hemodynamic load on the left or right ventricle. This load is compensated by the development of ventricular hypertrophy. The pattern of hypertrophy which develops is characteristic of each type of valvular lesion with concentric hypertrophy compensating the pressure overload of aortic stenosis, eccentric hypertrophy compensating the volume overload of mitral regurgitation and both concentric and eccentric hypertrophy compensating the combined pressure and volume overload of aortic regurgitation. While these patterns are characteristic, there is substantial variation in the geometric distribution of hypertrophy among individuals with the same valvular disease. This variability in turn produces variability in the amount of compensation from patient to patient. The geometric pattern of hypertrophy which develops primarily affects left ventricular function as it relates to the Laplace equation. An increase in the radius to thickness ratio increases wall stress while a decrease in this ratio decreases wall stress. Discussed below are the mechanisms by which the various geometries that develop in valvular heart disease affect loading to become adaptive or maladaptive or both.