Electrophysiological Characteristics and Radiofrequency Catheter Ablation of Accessory Pathway Connecting the Right Atrial Appendage and the Right Ventricle

The accessory pathway (AP) connecting the right atrial appendage (RAA) and the right ventricle (RV) is rare.We sought to investigate the feature of the AP connecting the RAA and the RV and the efficacy of radiofrequency catheter ablation via the endocardial access.We retrospectively analyzed 14 consecutive patients with 14 APs connecting the RAA and the RV managed by 15 procedures between January 2003 and December 2014.Ten patients presented as preexcitation during sinus rhythm. All APs had retrograde conduction. None had either antegrade or retrograde decremental conduction property. Ablation targeting the sites at the tricuspid annulus failed in all patients. They were successfully managed by ablating the atrial insertion sites with a median of 10.5 (range 5-28) radiofrequency applications. Electrograms at the successful target showed high amplitude atrial electrogram and low amplitude or no ventricular electrogram. The atrial insertion sites were at the floor of the RAA in 10 patients and inside the lower lobe of the RAA in the remaining 4 patients. The shortest distance between the successful target and the tricuspid annulus in the right anterior oblique projection was 19.7 ± 4.0 mm. There were no complications or recurrences during a median follow-up period of 4.3 (range 0.2-11.8) years.The APs connecting the RAA and the RV had typical conduction properties. The atrial insertion site favored the floor and the lower lobe of the RAA. Ablation targeting the atrial insertion sites was effective and safe, albeit multiple radiofrequency applications were needed.