Ventricular minor-axis dimensions were measured by echocardiography at end-systole (S8) and end-diastole (SD) in five groups of patients: (I) normal; (II) mitral stenosis; (III) compensated volume overload; (IV) idiopathic hypertrophic subaortic stenosis; and (V) congestive heart failure. Cardiac pump function was evaluated by determination of left ventricular volumes and ejection fraction (EF) from the echographic dimensions using formulae previously reported. The mean velocity of circumferential fiber shortening (VCF), a parameter of cardiac muscle performance previously obtained only by invasive methods, was determined from the echographic dimensions by the formula:[See Equation in PDF File]. The duration of minor-axis shortening (dt) was measured directly from the echocardiogram.Dimension and volume measurements in these groups of patients were similar to those reported in similar patients determined by angiographic methods. Measurement of the relative changes in echographic dimensions with systole (%&Dgr;S), EF, and VCFallowed separation of patients with clinical heart failure (group V) from normal subjects (group I). Patients in group II had reduced values for these parameters compared to group I. Those in III did not differ significantly, and those in IV had increased values. In general, VCF, EF, and %&Dgr;S showed similar trends, but individual patients sometimes differed. The findings reported here demonstrate the feasibility of evaluating ventricular function by a noninvasive method in a large group of ambulatory patients.