Effects of liriodenine on basal heart rate HR (A), peak LV pressure Pmax (B), and cardiac output CO (C). Liriodenine at its effective anti-arrhythmic dose of 10−7 g kg−1 showed no significant changes in HR, CO, and Pmax. By contrast, at 10 times the effective anti-arrhythmic dose 10−6 g kg−1, liriodenine produced a significant fall of 2.0% in HR and a significant rise of 5.8% in CO, but no significant change in Pmax. BA, basal state; DMSO, dimethylsulphoxide.