During diagnostic cardiac catheterization of 20 patients, 19 of whom had coronary artery disease (CAD), left ventricular (LV) performance was assessed by both muscle function indices and pump function indices. Muscle function indices included max dP/dt, Vpm, Vce5, and Vmax, the latter derived from both total pressure (TP) and developed pressure (DP) using catheter‐tip manometry. Pump function indices included LV ejection fraction (EF) and percent abnormally contracting segment (ACS), determined from biplane LV angiography. Muscle and pump function indices were also compared to the presence of the S3 (ventricular diastolic) gallop. Correlations existed between EF and Vmax (TP), EF and Vpm, percent‐ACS and Vmax(TP), and percent‐ACS and Vpm, with r values of 0.760, 0.777, −0.884, and −0.841, respectively. Vmax(TP) and Vpm also correlated quantitatively with the presence of the S3 gallop (p < 0.0005). Total pressure‐derived muscle function indices appear to adequately describe mean LV performance in patients with CAD and ACS, but these muscle function indices are probably highly dependent upon the size of the myocardial scar. Copyright © 1975 John Wiley & Sons, Ltd.