Evaluation of Left Ventricular Performance

In the first part of the study, the influence of changes in preload and afterload on mean circumferential fiber shortening velocity, Vcf, was investigated in the absence of any extrinsic cause for change in the contractile state of the left ventricle (LV) of seven dogs. In five of seven dogs in which afterload was controlled and contractility was unchanged, there was a significant negative correlation between LV end-diastolic pressure and mean Vcf expressed in circumferences per second (r = -.88 to -.97). In one dog there was a positive correlation (r = +0.847) and in another dog there was no significant correlation. Correlation as a