[Effects of isosorbide dinitrate on left and right ventricular systolic time intervals in patients after myocardial infarction].

The purpose of the study was to assess effects various doses of isosorbide dinitrate (ISDN) on left and right ventricular systolic time intervals in patients after myocardial infarction. The study population consisted of 25 patients who were eight weeks after their first transmural myocardial infarction. Twelve patients were given 5 mg of ISDN by an intravenous infusion for 60 min, and remaining 13 patients were given 10 mg of ISDN in a similar manner. Subgroups did not differ with respect to their initial arterial blood pressure (mean = 133.3) 82.9 vs 134.3 (87.1 mm Hg) and systolic pulmonary arterial pressure (mean = 27.2 vs 28.8 mm Hg). The infarct localization was also similar. Left ventricular systolic time intervals were calculated noninvasively, whereas right ventricular systolic time intervals were measured from simultaneous electrocardiographic, phonocardiographic and pulmonary arterial pressure tracings. Both left and right ventricular systolic time intervals were determined before and at 15 and 60 min after the drug administration. Student's t-test for unpaired and paired variables was used to test for statistical significance. Changes in the parameters studied at 60 min of the ISDN infusion were greater than at 15 min, and therefore only they are taken into account in the presentation of the results. During a 5 mg infusion of ISDN arterial blood pressure showed a tendency to decrease. Left ventricular ejection time shortened (-3.9%) and the pre-ejection period lengthened (+ 21.9%). The pulmonary artery pressure showed minimal tendency to decrease. The right ventricular systolic time intervals showed a similar tendency but the changes were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)