Intracardiac repair of lesions associated with atrioventricular discordance

Discordant atrioventricular (AV) connection is a rare congenital cardiac anomaly. Associated cardiac defects modify the physiology, clinical presentation, and surgical management of these patients. We have reviewed our overall experience with 90 patients operated for lesions associated with AV discordance between 1975-1990.

90 patients, consecutively operated between 1975-1990, were reviewed. Patients' charts, angiograms and echocardiograms were studied. Follow-up was obtained from our records or was requested from referring cardiologists/paediatricians. It was completed in December 1992. For the analysis of risk factors of early death we used P values by chi-squared and Fisher's exact test. For the analysis of the triangulated events, we used the Kaplan-Meier method. Variables associated with P value over 0.20 were eliminated.

90 patients aged 6 months-30 years (mean 9.1 year) underwent repair of cardiac anomalies associated with AV discordance. Three patients had total cavopulmonary connection; the remainder received biventricular repair. Most important associated malformations were ventricular septal defect (77), subpulmonary obstruction (68) and tricuspid valve anomaly (21). 59 patients received extracardiac valved conduit, 10 had tricuspid valve replacement. Thirteen patients died in hospital (14%). One year and 10 year actuarial survival rate was 84% and 70% respectively. The most significant factors for early death were: anatomically abnormal tricuspid valve (P < 0.0001), tricuspid valve regurgitation (P < 0.002), date of operation (P < 0.012), preoperative or perioperative complete heart block (P < 0.015), and tricuspid valve surgery (P < 0.05). Complete heart block developed in 17 (20%) out of 85 patients who did not have it preoperatively. During the follow-up, 22 intracardiac reoperations were necessary (4 died). 63 patients of 73 survivors (86%) remain in NYHA Class 1, 6 in Class 2 and 4 in Class 3.

The operative mortality was 14%. Twenty per cent of patients developed complete heart block. These results improved in the later part of the series (1985-1990); mortality decreased to 5% and incidence of heart block to 14%. Cardiac anomalies associated with AV discordance still present a surgical challenge. The data reported in our study should serve as a useful baseline for evaluation of newer surgical techniques, such as the "double switch" operation.