To create a noninvasive method of myocardial contractility assessment and to evaluate its diagnostical significance, 84 patients with ischemic cardiac disease and 17 healthy persons were clinically investigated including real-time ultrasound sectoral scanning, bicycle ergometry, selective coronaroarteriography and blood pressure measurement. Using noninvasive approximations of end-systolic and maximal isovolumic pressures and left ventricular volume values at the end of systole and diastole, we constructed end-systolic pressure-volume relations (ESPVR) which were compared with relations obtained by traditional methods. Results of this work show that a slope of ESPVR obtained from the study of data of one cardiac cycle is a reliable contractility index more sensitive to small alterations in the contractile state of the heart than traditionally used ejection fraction and circumferential fiber shortening velocity. We suggest that the ESPVR obtained in such a manner has some advantages because it takes into account influences of the afterload changes reflex consequences. The results also support application of this method to early diagnosis of ischemic cardiac disease.