The prenatal diagnosis of, and short-term outcome for, patients with congenitally corrected transposition.

Congenitally corrected transposition is a rare congenital anomaly, with only a few cases diagnosed and reported prenatally even in the largest fetal series. To determine the morphologic features and outcome for the lesion as recognized during fetal life, we reviewed the fetal and postnatal echocardiograms and medical records of 11 consecutive cases of congenitally corrected transposition. These were identified among 230 (4.7%) consecutive cases of structural cardiac disease referred to our fetal cardiology unit over a period of 4 years. The mean gestational age at diagnosis was 24.7 weeks. Reasons for referral were suspected complete transposition, abnormal position of the heart, and bradyarrhythmias. Associated cardiac lesions included an abnormal cardiac position in 6 cases, ventricular septal defect in 8, obstruction of the subpulmonary outflow tract in 6, tricuspid valvar displacement in 5, and complete atrioventricular block in 2. Only 3 of the cases had mild tricuspid regurgitation prior to birth. Termination was chosen in 4 cases with severe obstruction to pulmonary flow. Of the remaining cases, 2 patients died at 3 and 12 months after birth, respectively. Both developed significant tricuspid regurgitation associated with unexpected major arrhythmias. The remaining 5 patients are alive and relatively well at a mean follow-up of 25.4 months. An epicardial pacemaker was inserted in 1 because of complete atrioventricular block. We conclude that prenatal counseling must be guarded following the diagnosis of congenitally corrected transposition, even in fetuses with an apparently favorable state at initial examination. Some of these cases may undergo major and unexpected changes, particularly with regard to cardiac rhythm and tricuspid valvar function, with concomitant significant changes in prognosis.