Figure 51-3 Changes in ventricular physiology that accompany abnormal pressure and volume loading in human adolescents and adults. Schematic represents the changes in cross-sectional ventricular geometry that accompany abnormal pressure and volume loads. Data are measured and derived from catheterization and echocardiography of 30 adolescent and adult human subjects. Pressure overload triggers significant increases in wall thickness and wall thickness:radius ratio (h/r), but these compensatory mechanisms preserve σ within normal limits. Whereas volume overload causes dilation and enough hypertrophy to preserve normal σ_S , diastolic function deteriorates significantly. h-LV, posterior myocardial wall thickness; LVp, left ventricular pressure; r, radius of the LV chamber; σ_D end-diastolic wall stress; σ_S , peak systolic wall stress; * p < .01. (From Grossman W, Jones D, McLaurin LP: Wall stress and patterns of hypertrophy in the human left ventricle. J Clin Invest 56:56, 1975.)