Maximal treadmill stress test correlated with postexercise phonocardiogram in normal subjects.

One hundred normal subjects, mean age 51, who had had a simultaneous phonocardiogram and electrocardiogram at rest and after a double Master's test had a maximal treadmill stress test. Thirteen of 100 normal people (13%) had an abnormal maximal treadmill stress test with at least 1.0 mm of ischemic ST-segment depression. Ten of 29 normal subjects (34%) with a fourth heart sound and four of 11 normal people (36%) with a third heart sound after their double Master's test had an abnormal maximal treadmill stress test. Three of 71 normal subjects (4%) without a fourth heart sound and nine of 89 normal people (10%) without a third heart sound after their double Master's test had an abnormal maximal treadmill stress test. Normal subjects with an abnormal maximal treadmill stress test had a significantly higher incidence of fourth heart sounds (P <0.001) and third heart sounds (P < 0.02) than normals with a normal maximal treadmill stress test.