Background: Physiologic changes of pregnancy can predispose women to cardiac arrhythmias. Atrial fibrillation is rare in pregnancy and usually occurs in women with underlying cardiac anomalies.
Case: A young woman at 22 weeks of gestation presented with new-onset atrial fibrillation with rapid ventricular response. Thorough evaluation revealed atrial fibrillation with no underlying cause and ultimately required treatment with electrical cardioversion.
Conclusion: Lone atrial fibrillation in pregnancy requires exclusion of all possible etiologies before diagnosis. Cardioversion is the treatment of choice. Women with persistent atrial fibrillation require anticoagulation and rate control, as well as fetal growth surveillance and antenatal testing.