Resting and exertional haemodynamic effects of buccal nitroglycerin: acute and chronic discontinuous treatment in post-myocardial infarction patients with heart failure.

Abstract

The resting and exertional haemodynamic effects of acute and chronic discontinuous (one tablet every 6 h) treatment with 5 mg of buccal nitroglycerin (BN) have been assessed in nine postinfarction heart failure patients. At rest, pulmonary artery (PAP), pulmonary wedge (PWP), and right atrial pressures (RAP) were reduced by 42%, 55% and 77%, respectively, after the first dose and by 26%, 32% and 45%, respectively, after the chronic (three weeks) treatment with BN. During exercise, at the same workload, PAP, PWP and RAP were significantly reduced by 44%, 54% and 62%, respectively, after acute treatment and by 28%, 34% and 44%, respectively, after chronic treatment. The maximal workload (Kgm) increased by 179% and 166% and the exercise time increased by 78% and 71% after acute and chronic therapy, respectively. At the maximal workload, after acute BN, overall haemodynamics were better than in the basal state. PAP, PWP and RAP were still reduced by 19%, 31% and 31%, respectively, after acute treatment, while after chronic phase the results did not differ from control. The severity of cardiac failure, according to the Weber classification, was reduced by acute and chronic therapy. We can conclude that the buccal nitroglycerin showed clear efficacy in improving overall haemodynamic parameters both at rest and during exercise in post-myocardial infarction patients with heart failure. The discontinuous treatment maintained the effect of nitroglycerin without clear evidence of tolerance during chronic therapy.