Determinants of left ventricular dysfunction after anatomic repair of congenitally corrected transposition of the great arteries

Background. Early results for anatomic repair of congenitally corrected transposition of the great arteries are excellent with respect to right ventricular and tricuspid valve function. However, development of left ventricular (systemic ventricle) dysfunction late after repair remains a concern. In this study we sought to determine factors leading to late impairment in left ventricular performance. Methods. From August 1992 to July 2005, 44 patients (median age at surgery, 1.6 years; range, 0.6 to 39.6 years) with congenitally corrected transposition of the great arteries had anatomic repair. Left ventricular function and mitral regurgitation were evaluated by echocardiography at follow-up. Twenty-three patients had a Rastelli procedure, and 21 underwent an arterial switch. Twelve patients (27%) were pacemaker dependent at latest follow-up. Results. Early mortality was 4.5% (n = 2) with 1 late death as a result of leukemia. Median follow-up was 3.0 years (range, 7 days to 12.4 years). Left ventricular function remained unchanged (normal) in 35 patients, improved in 1 patient, and deteriorated in 8 patients (18%). Mitral regurgitation was unchanged in 30 patients, improved in 6 patients, and worsened in 8 patients (18%). Development of left ventricular dysfunction was significantly associated with pacemaker implantation (p = 0.005) and a widened QRS (> 20% > 98% percentile of normal; p = 0.03). Conclusions. Anatomic repair of congenitally corrected transposition can be performed with low operative mortality. However, late left ventricular dysfunction is not uncommon, with higher incidence in those requiring pacing and with a prolonged QRS. Resynchronization may be of value in patients requiring a pacemaker.