INTRACARDIAC REPAIR OF LESIONS ASSOCIATED WITH ATRIOVENTRICULAR DISCORDANCE

Objective. Discordant atrioventricular (AV) connection is a rare conge nital cardiac anomaly. Associated cardiac defects modify the: physiolo gy, 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. Methods. 90 patients, consecutively operated between 1975-1990, were reviewed. Pat ients' charts, angiograms and echocardiograms were studied. Follow-up was obtained from our records or was requested from referring cardiolo gists/paediatricians. It was completed in December 1992. For the analy sis 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. Results. 90 patients aged 6 months-30 years (mean 9.1 year) underwent repair of cardiac anomalies associated with AV di scordance. Three patients had total cavopulmonary connection; the rema inder received biventricular repair. Most important associated malform ations were ventricular septal defect (77), subpulmonary obstruction ( 68) and tricuspid valve anomaly (21). 59 patients received extracardia c valved conduit, 10 had tricuspid valve replacement. Thirteen patient s 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), tricus pid valve regurgitation (P < 0.002), date of operation (P < 0.012), pr eoperative or perioperative complete heart block (P < 0.015), and tric uspid 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 p atients of 73 survivors (86%) remain in NYHA Class 1, 6 in Class 2 and 4 in Class 3. Conclusions. The operative mortality was 14%. Twenty pe r cent of patients developed complete heart block. These results impro ved in the later part of the series (1985-1990); mortality decreased t o 5% and incidence of heart block to 14%. Cardiac anomalies associated with AV discordance still present a surgical challenge. The data repo rted in our study should serve as a useful baseline for evaluation of newer surgical techniques, such as the ''double switch'' operation.