Right Atrial Diverticulum in an Adult Woman with Left Bundle Branch Block.

Right atrial diverticulum is a very rare anomaly. It is an outpouching arising from the right atrial free wall. Clinical presentations vary widely but some cases are associated with supraventricular tachycardia and atrial flutter/fibrillation. The incidence/prevalence of this anomaly is not available because only a few cases have been reported. We report a 38-year-old female patient who presented to the Heart Clinic, Tehran, Iran in 2019 with a history of dyspnea and chest pain. Electrocardiography revealed left bundle branch block. Following a magnetic resonance imaging study, the patient was diagnosed with a right atrial diverticulum. She underwent surgical resection of the diverticulum. The post-operative course was uneventful and no recurrence of the arrhythmia was detected during the six months of follow-up. To the best of the authors' knowledge, this combination has not been described in the literature.