[The treatment of acute myocardial infarctions with beta-receptor-blockers. II. Hemodynamic effects of propranolol with and without combination therapy with nitroglycerin (author's transl)].

In 20 infarct patients, whose age varies from 43 to 78 years (m 59.6), continuous hemodynamic measurements were made to determine the cardiovascular effects of propranolol without and during a simultaneous infusion treatment with nitroglycerin. In cases of compensated ventricular function and pulmonary wedged pressures of 15 mm Hg or less (N = 10), a mean intravenous propranolol dose of 6.1 +/- 1.3 mg led to a significant reduction of the LVSWI and a simultaneous increase of the PCP by 31% of the control value (P less than or equal to 0.005). A simultaneously performed infusion treatment with nitroglycerin at a mean dose of 3.0 +/- 1.6 mg/h resulted in totally cutting off the propranolol-induced PCP increase, whereas a decrease of the heart rate and the LVSWI due to a beta-receptor-blockade remained completely unchanged. In the case of pre-existing congestion insufficiency of the left ventricle (N = 10) and of a pulmonary wedged pressure of above 15 mm Hg, the administration of a mean dose of propranolol of 5.8 +/- 1.1 mg for protection of the myocardium resulted in a partly disquieting decrease of the volume of cardiac output (P less than or equal to 0.005) which was 28% of the control value for the CI an 12% for the SVI. Correspondingly the left ventricular stroke work decreased to 18%. Nitroglycerin has a reducing influence on these changes, but not down to the initial level. In cases of sufficient ventricular function, propranolol has a favorable influence on the myocardial O2-metabolism via its depressor effect on heart rate and contractility. By means of nitroglycerin, an increase of the pulmonary wedged pressure occurring under this condition can be inhibited. However, in the case of a pre-existing congestion insufficiency, propranolol can lead to a partly disquieting depression of the circulation, which, apart from the hemodynamic risks, makes a rather unfavorable influence on the myocardial O2-metabolism seem likely.