The assessment of patients with situs inversus and corrected transposition of the great arteries.

Introduction: Congenitally corrected transposition of the great arteries (ccTGA) is a rare congenital heart defect. There are different subgroups according to the location of the heart in the thorax, apical position and situs.

Objectives: The purpose of this study was to assess pediatric patients with situs inversus (SI) ccTGA (SI-ccTGA), a rare subgroup of this condition, in detail.

Methods: The records of patients with SI-ccTGA followed between January 1, 2010 and January 1, 2019 in our clinic were analyzed retrospectively. Demographic features, associated cardiac defects, arrhythmias and follow-up data were recorded.

Results: Twenty-one out of 120 ccTGA patients had SI. The median age was 30 months (4 days-18 years). There were hemodynamically significant associated lesions in 85.7% (n=18) of the patients. A large ventricular septal defect was found in 16 patients (76.2%), severe pulmonary stenosis in 11 (52.4%), pulmonary atresia in six (28.5%), and severe tricuspid regurgitation in two (9.5%). Eleven out of 21 patients had biventricular physiology and eight had single-ventricle physiology. Bidirectional cavopulmonary anastomosis followed by a hemi-Mustard-Rastelli operation were planned for the remaining two patients. Twelve out of 18 patients with associated defects (66.6%) were operated and surgery was planned for three more patients (16.6%). The remaining three patients were scheduled for clinical follow-up. Arrhythmias developed in two (9.5%) patients on follow-up; ablation was performed in one of them and pacemaker implantation followed by cardiac resynchronization therapy was performed in the other. Two patients died during follow-up, one after a central shunt operation and the other preoperatively due to pneumonia and sepsis.

Conclusion: SI-ccTGA is not a mirror image of situs solitus ccTGA (SS-ccTGA) due to important anatomic and physiologic differences between them. SI-ccTGA patients have a lower risk of tricuspid valve regurgitation than SS-ccTGA patients. The timing of clinical presentation of these patients mainly depends on the type and severity of the associated lesions, as in all subtypes of ccTGA.