muscles and hemodynamics in dogs

The effects of dimethyltrilobine iodide (DMT) on the action potentials, the contraction of guinea pig papillary muscle in vitro and the hemodynamics in anesthetic dogs were studied. DMT (25 and 250μmol/L) prolonged the APD50, APD90 and ERP. DMT (250μmol/L) raised the APA. Concomitantly, DMT showed a direct positive inotropic effect on the isolated papillary muscles. In anesthetized dogs DMT (50μg/kg) did not significantly change the stroke volume and cardiac output. These results suggest that (1) the anti-arrhythmic effect of DMT may be related to the prolongation of ERP, and (2) the cardiac output did not decrease when DMT was used as an anti-arrhythmia agent.