[Vasodilator therapy in ischemic heart disease].

Abstract

A comparative study of venodilating and veno-arterial dilating drugs was conducted for clinical patients and for experimental animals. The subjects were 21 patients with ischemic heart disease associated with left ventricular failure. Fourteen patients received venodilators alone (Group I), and seven were administrated venoarterial dilators alone (Group II). At the time of the maximum effect, the two groups showed similar improvement. In Group I, the left ventricular filling pressure (LVFP) was reduced from 24 to 16 mmHg and the cardiac index (CI) was increased from 2.5 to 2.8 l/min/m2. In Group II, the LVFP was similarily reduced from 27 to 16 and the CI increased from 2.4 to 2.9. The effects of each drug on the total vascular resistance/LVEP were similar in both groups. In animals with partial occlusion of the left anterior descending artery, intravenous administration of nitroglycerin (TNG) or nitroprusside (NPS) lowered the aortic pressure stepwise at intervals of 10 mmHg from a mean of 130 mmHg. As a result, segmental shortening was improved either by TNG or NPS. However, when the systolic aortic pressure was decreased below 100 mmHg, segmental shortening of the ischemic area was aggravated in dogs receiving either drug. The end-diastolic length showed no difference between the dogs administrated TNG and NPS. When the effects of TNG and nifedipine (NFP) were compared to those in dogs with the old infarcted myocardium, both drugs produced improvement in hypokinetic segments. TNG induced a decrease in the end-diastolic length, whereas NFP revealed no changes, reflecting different modes of improvement.(ABSTRACT TRUNCATED AT 250 WORDS)