Left ventricular geometry and function in experimental heart failure.
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The shape of the left ventricle represents a key element in the adaptation of the heart to a variety of stresses. Therefore, hemodynamic deterioration should be reflected in alterations of shape. To investigate this hypothesis numerical descriptors of shape (single plane, two dimensional shape index, [4 pi (area)/(perimeter)2] and multiplane, three dimensional shape index, [36 pi (volume)2/(surface area)3] were obtained from two dimensional echocardiographic studies in dogs at baseline and then serially during development of early cardiomyopathy. Serial weekly injection of adriamycin (1 mg/kg) in 11 dogs to a cumulative dose of 144 mg/m2 resulted in no significant reduction in ejection fraction, stroke volume or cardiac index (P less than 0.05) but there was demonstrable loss of the ability of the heart to maintain an elliptical configuration during systole. Continuation of treatment to 244 mg/m2 resulted in gradual reduction in ejection fraction, stroke volume and cardiac index. Statistical correlation of the degree of reduction in ejection fraction with change in shape from diastole to systole (change in two and three dimensional shape indices) were -0.803 and -0.855, respectively. These data support the concept that the shape of the left ventricle relates to function, and the inability of the heart to develop an elliptical shape during systole may be an early indicator of impaired function prior to reduction in ejection fraction, stroke volume or cardiac index.
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