Figure 2. Erythromycin-induced prolongation of the monophasic action potential duration at 90% repolarization (MAPD90). The circles are data from individual hearts treated with 100 micro Meter erythromycin for 60 min. The squares represent means +/- SEM of 21 hearts (*P <0.001). The inset shows a representative example of a monophasic action potential at control and after 100 micro Meter erythromycin (Erythro) treatment.