Dextrocardia: an analysis of cardiac structures in 125 patients

Dextrocardia is associated with multiple and complex congenital cardiac anomalies. Precise anatomical diagnosis is essential for successful surgery. Spectrum of congenital malformations in cases of dextrocardia is based primarily on two-dimensional echocardiographic studies. The purpose of the current study was to use colour Doppler echocardiography in large number of patients.

Patients of dextrocardia were studied retrospectively, by reviewing database of our echocardiographic laboratory over last 10 years. Standard criteria for diagnosis of situs were used. Detailed segmental analysis for cardiac anatomy and associated malformations was done using previously suggested and well accepted terms and definitions. Cardiac anatomy was confirmed on catheterization and during surgery in few cases.

Of total 125 patients, dextrocardia was most common with situs inversus (39.2%) followed by situs solitus (34.4%) and situs ambiguous [26.4% (right isomerism in 18.4% and left isomerism in 8.0%)]. Mean age was 9.2+/-11.2 years (range; 3 days to 60 years), 82 males and 43 females. In situs inversus dextrocardia, majority (73.4%) had concordant atrioventricular (AV) connections while discordant AV connections and univentricular atrioventricular connections (UVAVC) were present in 12.2 and 14.3% patients, respectively. Majority of patients with concordant AV connections (72.2%) also had concordant VA (ventriculo-arterial) connections (conotruncal anomalies were commonest). Similarly, majority of patients with discordant AV connections (66.7%) also had discordant VA connections. Commonly (44.9%), these patients presented with decreased pulmonary blood flow (Qp). Total 28.6% patients had normal intracardiac anatomy (10.2% presented with rheumatic heart disease). In situs solitus dextrocardia, majority (51.2%) had AV concordance while discordant AV connections and UVAVC were present in 41.9 and 7.0% patients, respectively. In patients with concordant AV connections, majority (77.2%) had VA concordance (majority presented with increased Qp due to pre or post-tricuspid shunts). Similarly, majority of patients with discordant AV connections (88.9%) also had discordant VA connections (88.9% presented with decreased Qp). Only 7.0% patients with situs solitus dextrocardia had normal intracardiac anatomy. The striking features of right isomerism were male predominance (male:female ratio 2.2:1), cyanosis with decreased Qp in 86.9%, and high incidence of UVAVC and venous system anomalies (39.1% each). Striking features of left isomerism were biventricular ambiguous AV connections in all except one, presentation with increased Qp in 60.0% and presence of inferior vena caval interruption in 60.0% patients.

Present study, largest study of dextrocardia till date reconfirms that these patients have variable intracardiac anatomy depending upon their situs and types of segmental connections. These patients can present with different haemodynamic subsets, which can be correctly identified by colour Doppler echocardiography. Diagnostic accuracy and a better understanding of the various types of dextrocardia are essential, since improved surgical techniques have made it possible to correct many of these complex abnormalities.