Effects of Nitroglycerine Ointment On the Apexcardiogram and Systolic Time Intervals

Abstract

Ten patients with angina pectoris and a previous myocardial infarction were administered nitroglycerine (NTG) ointment, sublingual NTG, and a placebo ointment in a double-blind study. Left ventricular function was monitored noninvasively over 3 hours. Two patients showed no response to any of the NTG preparations and were excluded from the results. Left ventricular function improved in all remaining patients after both the sublingual NTG and the NTG ointment, but not the placebo ointment. This improvement was evidenced by a redution in a wave amplitude and duration of the apexcardiogram (ACG). At the same time the isovolumic relaxation time increased significantly and indicated a reduction in left atrial pressure. Also, a simultaneous improvement in the slope of the systolic wave indicated improved wall motion. The ΔLVET decreased, presumably because of a decrease in venous return due to peripheral pooling. None of these parameters changed significantly during the con trol period or after application of the placebo ointment. The onset of the effect after sublingual NTG was 3-5 minutes with a duration of 15-30 minutes. The NTG ointment had its onset of action at 20-30 minutes, a peak effect at 90 minutes, and a still significant effect at 3 hours. These findings clearly demonstrate the improvement in left ven tricular function that occurs in patients with ischemic heart disease in the absence of chest pain, and suggests that continual usage would be benefi cial even in patients with infrequent angina.