Surgical Problems Encountered in Interruption of Multiple Anomalous Pathways of Atrioventricular Conduction (Kent Bundles)

Abstract

Among the 160 patients operated on by the authors for anomalous pathways of atrioventricular conduction (APC), 15 had more than one APC, with 13 having two APCs and 2 having three. Nearly all possible combinations of APC were found. Four patients had Ebstein’s anomaly, all four having a right free wall and a septal pathway. The principal surgical problem, the identification of the APC, requires detailed electrophysiologic studies (EPS) before operation and intraoperatively. The suspicion of the presence of other APCs was raised by a wide QRS during reentrant tachycardia (RT) and chaning patterns of RT. Altera-tions of preexcitation patterns on the ECG during right and left atrial pacing and atrial flutter may denote other APCs. Atrial activation se-quences during RT were particularly helpful in finding APC with only retrograde function, as found in four patients, and also in demonstrat-ing septal pathways. Eight of the patients with 17 APCs had the APCs demonstrated before surgery. At surgery, EPS before and after division of the known APC was successful in identifying the additional APC in four patients. Failure to find the additional APCs during preoperative and intraoperative EPS may result from trauma to the pathway, close proximity of a second APC to the known APC, or suppression of the mani-festation of one pathway by the other. For these reasons three APCs were not identified until the postoperative period.