A series of the derivatives of 1-[2-hydroxy-3-(4-phenyl-1-piperazinyl])propyl]-pyrrolidin-2- one (MG-1) was synthesized and tested for electrocardiographic, antiarrhythmic, and antihypertensive activity as well as for alpha 1- and alpha 2-adrenoceptors binding affinities. Some of the compounds of this series slightly decreased the heart rate, prolonged P-Q, Q-T intervals and QRS complex. Only compound 7 (1-[2-hydroxy-3-(4-phenyl-1-piperazinyl)propyl]-pyrrolidine) possesses potent antiarrhythmic and a slight hypotensive properties, and affinity for alpha 1- and alpha 2-adrenoceptor. The results suggest that the antiarrhythmic and hypotensive effect of compound 7 and MG-1 is related to their adrenolytic properties, and that those properties depend on the presence of a phenylpiperazine moiety.