The left ventricular kinaetics of 29 coronary patients (pure angina and with sequela of myocardial infarction) was studies by biplane angiocardiography. Their contractility was assessed by measurement of the Vmax and VECmax indices derived from the relationship between contractile elements shortening speed-overall wall tension, in isovolumetric phase. An excellent relationship links the hypokinaetic area with decrease of the ejection fraction (SV/LSV): when the hypokinaetic area exceeded 20% of the overall endocardial surface, the ejection fraction deveased below 0.40, and signs of cardiac failure were manifest. Pure anginal patients at rest kept normal kinaetics, late diastolic volume, ejection fraction and myocardial mass. A myocardial hypertrophy develops in the areas adjacent to the fibrous scar. In some cases (group I) it compensates for the ventricular dysfunction; in other cases, it is not sufficient to compensate for the ejection fraction reduction. One must then admit the presence of diminished contractility in the areas adjacent to the fibrous scar, as is suggested by the increase of the late diastolic pressure, the decrease of the externel work of the left ventricle and of the contractility indices. Analysis of both the natural and post-operative courses in these patients shows that Vmax the ejection fraction and the hypokinaetic areas afford excellent criteria for prognosis and operability.