We compared ejection fraction, left ventricular end-diastolic pressure, cardiac index and the relation of left ventricular stroke work index to left ventricular end-diastolic pressure during rest and exercise in 60 patients with coronary artery disease. Left ventricular end-diastolic pressure was usually normal at rest (48/60) and abnormal during exercise (46/60) and did not correlate with ejection fraction. Cardiac index was insensitive, usually remaining normal until ejection fraction was < 0.40. Patients with a normal left ventricular stroke work index response to exercise had higher ejection fractions than those with an abnormal response (p < 0.05). However, 9 patients with normal ejection fractions had an abnormal exercise response. This may reflect loss of left ventricular reserve, abnormal compliance or clinically silent ischemia during exercise. Different indices of left ventricular performance may be widely disparate in coronary artery disease, and abnormalities are frequently apparent only during exercise.