Hemodynamic parameters of left-ventricular and left-atrial contractility and pumping function were examined in 47 males with postinfarction cardiosclerosis and no clinical signs of circulatory insufficiency and in 30 normal male subjects, exposed to isometric leg exercise with the highest possible compression force. At the height of exercise, normal subjects showed increased left-ventricular myocardial contractility along with the initiation of the Frank-Starling mechanism, spreading to the left atrium as well, while coronary patients responded to increased stress by growing left-atrial reservoir function during the first minutes of exercise, and activated left-atrial transport and pumping functions afterwards. Isometric leg exercise is capable of detecting left-atrial and left-ventricular pumping and contractility disorders in coronary patients.