It is issued from the fact that in acute myocardial infarction depending on expansion and localisation of the necrosis, on the degree of the possible functional adaptation of the not-affected myocardium or its previous injury must be reckoned with different changes of the haemodynamics. The sufficient judgment of the function of the left ventricle which is necessary for a differentiated therapy is possible only by the combination of several haemodynamic parameters. First results of direct measurements of pressure and volume of the left ventricle in patients with acute myocardial infarctions are demonstrated. Two types of haemodynamic constellation and their therapeutic influence are demonstrated. By the provable applanation of the functional curve of the left ventricle a change of the optimum working points develops; a secure differentiation between the reduction of the contractile function and reduced diastolic distensibility, however, is not only given on account of the displacement of the functional curve of the left ventricle. The results show that for a haemodynamic monitoring apart from the direct or indirect determination of the filling pressure of the left ventricle a practicable measurement of the cardiac output which must be repeated several times is necessary for an aimed therapy from haemodynamic aspects.