Figure 3: Effect of icariin and sildenafil on isoproterenol-induced electrocardiographic changes. (a) Vehicle control, (b) isoproterenol treated, (c) icariin per se, (d) sildenafil per se, (e) icariin 1+ isoproterenol, (f) icariin 5+ isoproterenol, (g) icariin 10+ isoproterenol, (h) sildenafil + isoproterenol