Case Report: Radiofrequency Ablation of an Epicardial Left Lateral Accessory Pathway

Objectives: A 17-year-old boy presented with aborted sudden cardiac death due to ventricular fibrillation while playing football. He had a history of sudden onset tachycardia episodes without ECG documentation. After successful resuscitation baseline ECG revealed ventricular preexcitation (VPE) corresponding to a left sided accessory pathway (AP). The patient then underwent two unsuccessful endocardial catheter ablation procedures of a left lateral AP at a referring hospital.

Methods: At our hospital, we performed a third EP procedure. Antegrade refractory time of the AP was 280 ms and SPERRI in atrial fibrillation was 270 ms. Endocardial ablation using a retrograde, as well as an antegrade, approach through a patent foramen ovale again did not eliminate the AP. Following this procedure, an epicardial ablation approach was suggested to the patient. The fourth procedure was performed under deep sedation. After placing a CS, RV and mapping catheter endocardially, the earliest ventricular activation was again found at the lateral mitral annulus. Epicardial access was obtained using a pericardiocentesis kit, Tuohy needle and 8.5 Fr sheath (Agilis EPI Steerable Introducer, Abbott). Epicardial mapping included 3D electroanatomic and activation mapping (CARTO 3, Biosense Webster, Diamond Bar, California, United States) using an irrigated tip catheter (Thermocool Smarttouch SF, Biosense Webster). Mapping was performed during sinus rhythm targeting earliest ventricular activation, which was found opposite the corresponding endocardial site. Before ablation, coronary angiography revealed a discrete separation of the target site from the left circumflex artery. Careful ECG monitoring for ST changes was performed during ablation. RF application with 35 W led to successful elimination of VPE after 4 seconds. After a waiting time of 30 minutes the epicardial sheath was removed.

Result: There were no procedural complications. Follow-up at 3 and 6 months revealed no VPE on ECG and the patient was without symptoms.

Conclusion: In special cases, a subxiphoid percutaneous epicardial ablation approach might be warranted to eliminate a clinical high-risk accessory pathway.