Electromechanical effects of newly synthetized propafenone derivatives on isolated guinea-pig heart muscle preparations.

Inotropic, chronotropic and beta-adrenoceptor blocking activities of the newly synthetized propafenone derivatives 1-(2-(3-diethylamino-2-hydroxypropoxy)phenyl-3-phenyl-1-propanone hydrochloride (AM 03), 1-(2-(2-hydroxy-3-(1-piperidyl)propoxy)phenyl)-3-phenyl-1-propanone hydrochloride (AM 05), N,N-dimethyl-N-(2-hydroxy-3-(2-(3- phenylpropionyl)phenoxy)propyl)-propylammonium iodide (TH 41), N,N- diethyl-N-(2-hydroxy-3-(2-(3-phenylpropionyl)phenoxy)propyl)-methylammon ium iodide (AM 07), and N,N-diiso-propyl-N-(2-hydroxy-3-(2-(3-phenylpropionyl)phenoxy)prop yl)- methylammonium iodide (AM 09) studied in isolated, electrically stimulated papillary muscles and spontaneously beating right atria of guinea pigs. In comparison with propafenone the tertiary amines AM 03 and AM 05 showed a higher negative inotropic potency, while the quarternary amines TH 41, AM 07 and AM 09 were less effective. With regard to their negative chronotropic action, AM 03 and AM 05 were more and TH 41, AM 07 and AM 09 less potent than the parent drug. In contrast to propafenone none of its derivatives exerted beta-adrenoceptor blockade at the concentrations studied.