Successful catheter ablation using real-time ultrasound-assisted 3-D electroanatomical mapping system for atrioventricular accessory pathway in a 1-year-old girl with criss-cross heart

Criss-cross heart, defined as crossing of the long axis of the atrioventricular (AV) valves, is an extremely rare congenital heart defect. The unusual arrangement of the cardiac inlets observed in criss-cross heart was first described by Lev and Rowlatt in 1961. The term “criss-cross heart” was initially coined by Anderson et al in 1972. The reported incidence of criss-cross heart is no greater than 8 per 1,000,000 and accounts for o0.1% of congenital heart defects. According to the relationship of the AV connection, criss-cross heart is divided into 2 types: criss-cross heart with AV concordance is known as concordant criss-cross heart, whereas criss-cross heart with AV discordance is termed discordant criss-cross heart. Catheter ablation of complex congenital heart defects is clinically challenging because the embryology of the cardiac conduction system, particularly the AV node, is complex and the associated anatomical structures are difficult to identify accurately. The CARTOSOUND system (Biosense Webster Inc, Diamond Bar, CA), an ultrasound-based 3-D imaging modality for catheter navigation, was introduced by Forleo et al in 2011. Because this technique provides anatomically accurate volumes from real-time 2-D intracardiac echocardiographic images, it might have particular utility in accessing challenging anatomical structures, as observed in congenital heart disease. Herein, we present a very rare case of successful catheter ablation of concealed accessory pathway using the CARTOSOUND system in a 1-year-old girl with criss-cross