[Prenatal effect of fenoterol (Partusisten) on the heart in the presence of verapamil].

The effect of fenoterol and fenoterol + verapamil on fetal hearts obtained from termination of pregnancy and surviving in nutrient solution was investigated. In 10--20-week-old fetal hearts, under the influence of fenoterol, a concentration-dependent increase was observed in spontaneous rate and contractility. A close linear correlation was found between the fetal age and the tachycardiac effect of the drug. The positive chronotropic and inotropic effect of fenoterol was significantly decreased by a therapeutically meaningful concentration (20 micrograms/l) of verapamil. The results are in favour of the suggestion that the inhibition by verapamil of the in utero fetal tachycardiac effect of fenoterol might occur, at least in part, in the fetal heart itself.