Surgical ablation of posterior septal accessory pathways in the Wolff-Parkinson-White syndrome by a closed heart technique

Abstract

The conventional technique for surgical ablation of posterior septal accessory pathways in the Wolff-Parkinson-White syndrome has been associated with a significant incidence of inadvertent permanent atrioventricular block. We report our experience with the ablation of posterior septal accessory pathways by a closed heart technique that combines mobilization of the posterior septal atrioventricular fat pad and exposure and cryoablation of the atrioventricular junction. The operation is performed on the normothermic beating heart. Consequently, atrioventricular node-His bundle conduction and accessory pathway conduction can be continuously monitored to avoid inadvertent injury to the atrioventricular node-His bundle system. This technique for ablation of posterior septal accessory pathways was used in 13 patients (four female and nine male patients, aged 14 to 59 years). The heart was exposed via a median sternotomy. Epicardial mapping was used to determine the insertion of the accessory pathway either to the left ventricular process or the immediately adjacent right or left ventricular free wall. Normothermic cardiopulmonary bypass was used in nine patients and omitted in four. Accessory pathway conduction disappeared in the course of dissecting the fat pad from the atrial wall and atrioventricular sulcus in all patients. Cryosurgical lesions were then applied to the atrioventricular sulcus in the area of interest (while monitoring atrioventricular conduction) to ensure transmural fibrosis of the atrioventricular ring. All patients tolerated the procedure well. There were no complications and, specifically, not a single instance of atrioventricular block. All patients remain arrhythmia free after a follow-up period of 10 months. This closed heart approach allows the ablation of posterior septal accessory pathways while the electrocardiogram is being monitored. It obviates the need for aortic cross-clamping and minimize the risk of inadvertent heart block.