Three-dimensional cardiac dynamics of the closed chest canine

A noninvasive, three-dimensional imaging system was used to map the left and right epicardial shapes and surface displacements over the cardiac cycle for 11 canine subjects. Average displacements were calculated for each time period and for different areas of the heart surfaces. Volume changes and the movements of the center of mass were calculated. For the ventricular areas, significant expansive movement was found in isovolumic contraction, and a consistent inward collapse was found beginning in isovolumic relaxation and continuing into mid-diastole. Ejection began in the posterior, basal corner of the ventricles and spread anteriorly and apically. A typical wall motion possibly due to vessel movement was found along the basal areas of the heart. Points of maximum and minimum volume did not correspond to end-diastole and end-systole. The center of mass of the heart showed a shift towards the apex and sternum during filling and a shift towards the base and spine during contraction and collapse, with no significant movement from side to side.<
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