Management of supraventricular tachycardia during hexoprenaline therapy for preterm labour: benefit of cardioselective beta blockade?

A 29-year-old woman presented with preterm labour at 32 weeks of gestation. Tocolytic treatment was started with intravenous hexoprenaline. Twenty-four hours after initiation of treatment, the patient developed supraventricular tachycardia, resistant to digoxin and verapamil. Medical treatment with metoprolol finally restored sinus rhythm. We observed no adverse effects on the fetal heart rate nor on the umbilical cord blood flow.