Isolated pulmonary vein tachycardia during atrial fibrillation

Abstract

A 67-year-old man with a 5-year history of drug-refractory persistent atrial fibrillation (AF) lasting for 7 months prior to the procedure underwent radiofrequency (RF) catheter ablation. The initial AF cycle length (CL) in the coronary sinus (CS) was 162 ms. Ablation was started with isolation of the left pulmonary veins (PV) by creating a continuous linear lesion around the ipsilateral PVs in a distance of *1 cm proximally to the PV ostia. Electrical isolation was confirmed by a single circumferential mapping catheter (Lasso, Biosense-Webster, Diamond Bar, CA, USA) which was sequentially placed in the superior and inferior left PV. After electrical disconnection of the left PVs, accompanied by a slow dissociated rhythm in both PVs, isolation of the right PVs was attempted using the same technique. Initially, a long continuous circular lesion was deployed surrounding both right PVs. Afterwards, potential electrical sleeve conductions of both right PVs were specifically targeted by repeatedly replacing the Lasso catheter in the superior and inferior right vein. However, complete elimination of all PV potentials could only be achieved in the right inferior PV. In contrast, the right superior PV (RSPV) still demonstrated PV potentials with a CL shorter than CS–CL. Although a total of 18 min of RF has been applied in order to isolate the right PVs, apparently no elimination of PV potentials in the RSPV could be achieved. Since the very short CL of the RSPV (CL = 114 ms, Fig. 1) was suggestive for a driving role of this vein in the AF process, external electrical cardioversion was performed to clarify the earliest PV activation during sinus rhythm and, thereby, to facilitate electrical isolation of this potentially ‘‘culprit vein’’. However, no potentials could be demonstrated in the RSPV after cardioversion (Fig. 2). Furthermore, pacing from within the PV demonstrated RSPV exit block. Thus, this observation retrospectively reveals the presence of a persistent PV tachycardia in the electrically isolated RSPV coexisting with ongoing and independently operating AF in the atria. Since complete isolation was confirmed, AF was reinduced and the ablation procedure was continued using the stepwise ablation approach. This approach comprises PV isolation, bi-atrial defragmentation, defragmentation and/or electrical isolation of the coronary sinus and leftatrial linear ablation. The aim of the mapping and ablation process is to gradually eliminate AF sources as represented by an incremental increase of the overall AFCL resulting in AF termination either directly to sinus rhythm or to atrial tachycardia(s) which are targeted until achievement of sinus rhythm [1, 2].