Double-Inlet single ventricle associated with transposition of the great arteries, situs inversus, and criss-cross heart in an unrepaired adult: A case report

Abstract

The single ventricle represents a group of complex congenital heart diseases characterized by the mixing of oxygenated and deoxygenated blood, chronic cyanosis, and ventricular volume overload. The combination of a double-inlet single ventricle with transposition of the great arteries, situs inversus, and a criss-cross heart is extremely rare, reported only in isolated cases in the literature. Most of these patients require early palliative interventions, such as the bidirectional Glenn procedure and eventual Fontan circulation, to optimize oxygenation and reduce ventricular overload. We present the case of a 26-year-old man with a history of cyanotic congenital heart disease, scheduled for surgery at age 12 but managed conservatively due to high surgical risk. Survival into adulthood without definitive surgical correction is likely due to a favorable hemodynamic balance conferred by pulmonary stenosis, which limits pulmonary overcirculation and protects the dominant ventricle. Currently, the patient remains clinically stable, classified as New York Heart Association functional class II, with no recent episodes of cardiovascular decompensation, hospitalizations, or documented thromboembolic events. This case highlights the anatomical rarity and underscores the importance of specialized follow-up in adults with complex univentricular congenital heart disease who have not undergone corrective surgery.