Ritodrine-induced atrial fibrillation during pregnancy

Abstract

Atrial fibrillation (AF) rarely occurs during pregnancy. Beta2-mimetics are widely used for treating of preterm labor in Japan and five cases of AF induced by beta2-mimetics in pregnant women have been reported. There is scant information available regarding the diagnosis and management of AF related to beta2-mimetic therapy during pregnancy. We report here two cases of ritodrine-induced AF. Case 1 : a 35-year-old nulligravida, who had been treated preterm labor by intravenous ritodrine, presented tachycardia with a rate of 140 bpm at 29 weeks’gestation. A 12-lead electrocardiogram revealed AF and the ritodrine was immediately stopped. A beta-blocker was used to control the heart rate. The AF reverted to a normal sinus rhythm three days later. Case 2 : a 37-year-old multipara, who presented AF at 35 weeks’gestation while receiving oral ritodrine treatment. The maternal heart rate was 140 bpm at the time of diagnosis and the AF spontaneously reverted to a normal sinus rhythm the day following cessation of ritodrine. We reviewed the two present and five previously literally reported cases of AF occurring during pregnancy. The heart rate at AF onset was reported for five cases and all (100%) showed tachycardia greater than 140 bpm. The duration from cessation of beta2-mimetic to reversion to a normal sinus rhythm was described in six cases, with a median reversion time of 8.5 hours (range, 4-73 hours), of which three (50%) spontaneously reverted to sinus rhythm without cardioversion. When a pregnant woman receiving ritodrine shows tachycardia around 140 bpm, a 12-lead electrocardiogram should be performed to find AF, and ritodrine should be immediately discontinued when a diagnosis of AF is confirmed. [Adv Obstet Gynecol, 73 (3) : 207-212, 2021 (R3.8)]