Indices of left ventricular systolic function derived by computer analysis of digitised M-mode echocardiograms

In order to determine the value of computer-assisted analysis of echocardiograms we digitised 980 M-mode studies in normal subjects and patients with pressure and volume overload and heart muscle disease to derive left ventricular dimensions (D), peak systolic rate of change of dimension, normalized for instantaneous dimension (dD/dt/D), mean velocity of circumferential fiber shortening (mean Vcf) and percentage fractional shortening (%FS). The systolic phase indices which, in these patients averaged greater than normal in those with aortic stenosis and hypertrophic cardiomyopathy and lower than normal in those with aortic regurgitation, mitral stenosis and dilated cardiomyopathy, were closely related to each other in all categories of patients. Measurement of % FS appears to describe left ventricular function as well as the more complex indices (mean Vcf, peak dD/dt/D).