The effects of antianginal drugs on left ventricular function in patients with effort angina pectoris. Comparison among isosorbide dinitrate, nifedipine and propranolol by PANOVA.

To study the acute effects of ISDN, nifedipine, propranolol and placebo on cardiac function in patients with myocardial ischemia and to characterize their hemodynamic effects by PANOVA, we repetitively performed exercise radionuclide angiography (RNA) following random assignment of each drug in 20 patients with effort angina pectoris. We obtained exercise response curves of hemodynamic parameters determined by RNA. ANOVA was performed to analyze the sizes (average height) of those response curves, and PANOVA (principal component analysis, PCA, combined with ANOVA) to analyze differences in the profiles (patterns) of the curves. By conventional analysis of variance followed by a Scheffé type multiple comparison, end-diastolic volume after ISDN, which was significantly smaller than those after the other drugs at rest (p less than 0.01), was similar to those after nifedipine and propranolol during exercise (96.4 +/- 4.6 ml/m2 vs. 94.8 +/- 5.1 ml/m2 and 97.1 +/- 4.9 ml/m2, respectively). Systemic vascular resistance after nifedipine, which was also significantly lower than those after the other drugs at rest (p less than 0.05), was not different from that after placebo during exercise (16.9 +/- 1.1 units vs. 18.7 +/- 1.3 units). Thus, this analysis was considered insufficient to fully differentiate the characteristics of each drug. By PANOVA, the profiles of LVEF with these three antianginal drugs were similar, and significantly differentiated from that of placebo (p less than 0.05). This indicated that the antianginal effect could be represented by the profiles of the response curves of LVEF, using PANOVA. Evaluating the underlying hemodynamic mechanisms of these drugs by PANOVA, ISDN was significantly differentiated from nifedipine and propranolol by the profile of end-diastolic volume (p less than 0.05). The characteristics of nifedipine were clearly demonstrated by the size and profile of systemic vascular resistance, and those of propranolol were also differentiated by the size and profile of the double product and P-V index. Hence, it is concluded that with the aid of PANOVA, the changes in hemodynamic parameters during ischemia can be evaluated in a manner that is highly effective in differentiating the characteristics of the effects of antianginal drugs in patients with angina pectoris.