A polygraphic study involved 122 patients with acute myocardial infarction mostly of transmural nature. In 42 cases using parallel catheterization, barograms of the right portion of the heart and pulmonary artery were recorded. The above non-invasive techniques were tested in relation to their suitability for the indirect determination of the pulmonary circulation pressure. Mathematically substantiated formula are presented designed for the indirect measurement of right atrium and pulmonary pressure. The localization of the primary infarction in the left ventricle anterior wall, recurrent necrosis of the cardiac muscle, attendant essential hypertension and diabetes mellitus are shown to be associated with a more pronounced pulmonary hypertension. An attempt is made to elicit the mechanisms of pulmonary hypertension by correlating the phasic structures of the systole of the right and left ventricles.