Incidental Discovery of Double Inversion Physiology with a Novel Right Atrial to Left Ventricular Shunt During Workup for Acute Abdominal Pain and Uterine Leiomyomas: A Case Report

Background: Complete situs inversus with levocardia and congenitally corrected transposition of the great arteries (CCTGA) is an exceptionally rare and complex congenital heart defect. We report a unique case featuring a previously unreported direct right atrium to left ventricle (RA-LV) shunt, discovered incidentally during an abdominal workup, which highlights the extraordinary compensatory capacity of double inversion physiology. Case presentation: A 35-year-old woman presented with acute abdominal pain. Pelvic and abdominal ultrasonography revealed multiple large uterine leiomyomas and incidentally identified complete situs inversus. Contrast-enhanced multidetector computed tomography (MDCT) confirmed complex cardiac anomalies, including CCTGA, a large perimembranous ventricular septal defect, patent ductus arteriosus, right aortic arch with mirror-image branching, and severe pulmonary hypertension. Crucially, a novel direct RA-LV shunt was identified, creating a paradoxical pathway that likely maintained balanced circulation for three decades. Laboratory tests showed an acute inflammatory response correlating with a 53-mm abdominal wall muscular lesion and suspected localized bowel ischemia. Due to advanced pulmonary vascular disease, cardiac surgery was deemed high-risk and deferred; the patient was managed conservatively for her abdominal complaints and discharged with informed consent. Conclusions: This case underscores the critical role of high-resolution MDCT in mapping complex, atypical intracardiac shunts that echocardiography might miss in inverted hearts. Clinicians must maintain a high index of suspicion for profound congenital anomalies whenever visceral heterotaxy is incidentally detected, ensuring comprehensive cardiovascular evaluation and lifelong multidisciplinary surveillance.