Fig. 1. Effects of methylmethacrylate monomer (MMA) on myocardial contractile force in modified normal Tyrode solution. Effects of 0.5 mm, 1.5 mm, and 4.7 mm MMA on peak force (PF) (A ) and maximum rate of force development (dF/dt-max) (B ) at various stimulation rates in guinea pig papillary muscles (n = 6). Effects of 1.5 mm MMA on PF (C ) and dF/dt-max (D ) at each stimulation rate (n = 6). *Differences from baseline (P < 0.05). Differences from stimulation rates of †2 and ‡1 Hz (P < 0.05).