Hemodynamic and metabolic effects of nitroglycerin ointment in pacing-induced angina pectoris

Hemodynamic and metabolic effects of nitroglycerin ointment (40 mg nitroglycerin) were tested on 15 patients with clinical evidence of stable angina. Basal value (B) and atrial pacing (AP)-dependent changes were evaluated before and 30 min after ointment administration. After treatment tension time index (TTI) basal value showed a 19% reduction (p less than 0.05). Compared to the control a lesser AP-dependent increase was also noted (27%, compared to 45%; p less than 0.005). According to TTI reduction, MVO2 showed an evident decrease both in basal conditions and during AP (21% and 29.6%, respectively). On the contrary, diastolic pressure time index (DPTI) does not result significantly influenced by the treatment. Consequently, DPTI/TTI ratio increase is largely the result of TTI reduction, which is well correlated to myocardial oxygen demand. Coronary sinus blood flow decrease (16% and 27% under basal conditions and during AP, respectively) confirms that the therapeutic efficacy of the ointment does not result from an increase in myocardial oxygen supply. Finally, during AP nitroglycerin ointment resulted in a significant decrease in myocardial lactate release (L% mean value ranges from-17.5% to 3.4%; p less than 0.001). Such an improvement probably reflects a primary influence of the drug on the extracoronary vascular bed.