Catheter ablation of septal accessory conduction pathways with high frequency electric current]

In 58 symptomatic patients with septal accessory atrioventricular pathways, attempts at catheter ablation of the pathway were made using 500-kHz radiofrequency current. The methodological approach (introduction and final positioning of the ablation catheter) was dependent on the anatomical site of the accessory pathway. Right anteroseptal pathways were accessed via a jugular venous route, whereas a femoral venous route was used for right mid- and posteroseptal pathways. In these pathways, ablation was attempted from an atrial catheter position. Left posteroseptal pathways were located via mapping of the coronary sinus and were ablated either from the left ventricle or (in 3 cases) from the vena cordis media. Utilizing a deflectable catheter with a 4-mm tip electrode, ablation attempts were successful in 54 patients (93%) with a median of 12 radiofrequency current pulses of an average 24.9 W of power and 23.2 s length. The mean duration of the sessions was 4.6 h. Impairment of physiological conduction (first-degree AV block) was observed in 1 patient; complete heart block was never induced. Recurrences after initially successful ablation necessitated a repeat session in 2 patients. One patient died 3 days after successful ablation of a posteroseptal accessory pathway. Septal accessory pathways may be ablated using radiofrequency current with an efficacy and safety comparable to free-wall accessory pathways and with good preservation of physiological AV node-His bundle conduction.