The amount of local tissue deformation at the equatorial region of the left ventricle is quantitated by the ratio of the instantaneous cross-sectional area of a tissue element to the cross-sectional area at end-diastole. The area ratio, AR, was computed for the circumferential and longitudinal, apex to base, direction throughout the cardiac cycle from catheterization and cineangiographic data on 36 patients. The patients were divided into four groups: normal left ventricualr function—15, compensated volume overload—6, decompensated volume overload—9, and congestive cardiomyopathy—6. The peak longitudinal area ratio was elevated in the compensated group (P <0.001) and not statistically significant from normal in the decompensated group. A larger fraction of the cardiac cycle was required to reach the peak longitudinal (p <0.01) and circumferential (p <0.05) area ratio in the compensated group. The volume overload compensatory process apparently involves a change in the relative magnitude and timing of tissue deformation. The hypo-contractile ventricle was characterized by a reduction in the sum of the logitudinal and circumferential area ratios, which for all six patients in the congestive cardiomyopathy group, had a value less than any of the other thirty patients.

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