Fig. 1.

Metoprolol delayed the onset of heart failure in rats with pre-existing PAH. A The median day to failure signs was increased from 23 to 31 days post MCT injection (N = 12 MCT, 15 MCT + BB rats, ** P < .01, Mantel-Cox test). Echocardiography measurements of RV function were performed on the day of heart failure signs (MCT) or the median survival day of MCT rats (CON and MCT + BB). B RV wall thickness was reduced in MCT + BB rats compared to MCT, indicating attenuation of hypertrophy. C Stroke volume was increased by BB D Cardiac output was not significantly increased with BB (P = .09 vs MCT). B-DN = 9 CON, 7 MCT, 5 MCT + BB rats. One-way ANOVA. * P < .05, *** P < .001.