Clinical implications of dextrocardia based on four visceroatrial situs studies

Background: Previous studies on congenital heart diseases (CHD) associated with dextrocardia were based on selective patient databases and did not reflect the full spectrum of dextrocardia in the general population. Additionally, these studies had complex classification and presentation. Nor did these studies elaborate on the distribution of the associated CHD's complexity, the various segmental connections, and associated CHD among the four visceroatrial situs. Methods: We retrospectively reviewed the medical records of 211 children with primary dextrocardia. We used a segmental approach to diagnose CHD. We then analyzed and compared the distribution of the above-mentioned issues among the four visceroatrial situs. Results: Dextrocardia occurred most commonly with situs inversus (52.6%), followed by situs solitus (28.4%), asplenia (17.1%), and polysplenia (1.9%). Although some patients had a structurally normal heart (22.7%) or they were associated with simple CHD (17.5%), most patients had complex CHD (59.7%) consisting of a single ventricle (34.6%) or conotruncal anomaly (25.1%) (double-outlet right ventricle [7.6%], corrected transposition of the great arteries [6.2%], complete transposition of the great arteries [5.7%], tetralogy of Fallot [4.7%], etc.). Situs inversus or polysplenia had a higher prevalence of a structurally normal heart or associated with simple CHD, two patent atrioventricular (AV) valves connections, and biventricular AV connections. Situs solitus or asplenia had a higher prevalence of associated complex CHD, common AV valve connection, univentricular AV connection, pulmonary outflow tract obstruction, and anomalous pulmonary venous drainage. Conclusion: Our study finds that situs inversus is the most common visceroatrial situs in dextrocardia. Although some patients had a structurally normal heart or were associated with simple CHD, most patients have associated complex CHD consisting of a single ventricle or conotruncal anomaly. Dextrocardia is associated with a higher incidence of complex CHD in situs solitus and asplenia groups than in situs inversus and polysplenia groups.