Successful management of supraventricular tachycardia in a fetus using fetal magnetocardiography.

We report a fetus at 33 weeks of gestation with supraventricular tachycardia, which was successfully managed by transplacental administration of an antiarrhythmic agent. Fetal magnetocardiography (fMCG) revealed supraventricular tachycardia of the long RP' tachycardia type. Transplacental administration of sotalol, instead of digoxin, was selected as the first-line drug, and it successfully converted supraventricular tachycardia to sinus rhythm. The diagnosis of the type of supraventricular tachycardia was confirmed by electrocardiography after birth. Sotalol was also effective after birth to maintain sinus rhythm. This case demonstrates that fMCG is potentially useful for prenatal differentiation of the type of supraventricular tachycardia and for prenatal treatment of fetal tachyarrhythmias.