[Predictive factors for late complete atrio-ventricular block after surgical treatment for congenital cardiopathy]

Abstract

The late occurrence of complete atrio-ventricular block (CAVB) after cardiac surgery is rare but potentially responsible for cases of late sudden death. We searched for factors allowing prediction of this complication, retrospectively reviewing the case notes of 11 patients in hospital with complete AVB, 2 months to 10 years after correction of a cardiac malformation. All had a normal pre-operative ECG. The diagnosis had been made based on symptoms in 8 patients: syncope or collapse (4 cases) symptoms on effort (3 cases) or fatigue (1 case). In the others the diagnosis had been made on ECG. The block was infra-His in 5 patients who had electrophysiology. ECG analysis showed that all the patients had CAVB immediately post-operatively lasting 3-14 days. After restoration of conduction the ECGs showed the following anomalies compared to the pre-operative ECGs: long PR (1 case), long PR + right bundle branch block (2 cases), long PR + left axis deviation (1 case), RBBB + left deviation or rotation of the QRS axis (3 cases), long PR + RBBB + left axis deviation (4 cases). All of these patients had been fitted with a cardiac stimulator. In conclusion, the children who had CAVB immediately post-operatively lasting more than 48 hours and who then had an ECG showing different QRS compared to the pre-operative QRS and/or long PR had a risk of late complete AVB. These patients should have electrophysiology and a stimulator must be implanted in those who have an infra-His block.