Electrophysiological Breakthroughs From the Left Atrium to the Pulmonary Veins

TLDR

The necessary extent of ostial ablation to electrically isolate pulmonary vein myocardial extensions that trigger atrial fibrillation from the left atrium remains undefined. In 70 patients, circumferential 10‑electrode mapping during sinus rhythm or left‑atrial pacing identified perimetric activation patterns, and ablation was targeted at segments with earliest breakthrough until pulmonary‑vein disconnection was achieved. A total of 162 pulmonary veins were ablated, with radiofrequency at breakthrough sites eliminating potentials in 34 veins and requiring additional segments in 77; early arrhythmia recurrence occurred in 31 patients, often due to a single recovered breakthrough, demonstrating that partial perimetric ablation at specific breakthroughs can disconnect pulmonary veins despite extensive muscle coverage.

Abstract

Background —The extent of ostial ablation necessary to electrically disconnect the pulmonary vein (PV) myocardial extensions that initiate atrial fibrillation from the left atrium has not been determined. Methods and Results —Seventy patients underwent PV mapping with a circumferential 10-electrode catheter during sinus rhythm or left atrial pacing. After assessment of perimetric distribution and activation sequence of PV potentials, ostial ablation was performed at segments showing earliest activation, with the end point of PV disconnection. A total of 162 PVs (excluding right inferior PVs) were ablated. PV potentials were present at 60% to 88% of their perimeter, but PV muscle activation was always sequential from a segment with earliest activation (breakthrough). Radiofrequency (RF) application at this breakthrough eliminated all PV potentials in 34 PVs, whereas a secondary breakthrough required RF applications at separate segments in 77; in others, >2 segments were ablated. A median of 5, 6, and 4 bipoles from the circular catheter were targeted in the right superior, left superior, and inferior PVs, respectively, to achieve PV disconnection. Early recurrence of arrhythmia was observed in 31 patients as a result of new venous or atrial foci or recovery of previously targeted PVs, most related to a single recovered breakthrough that was reablated with local RF application. Conclusions —Although PV muscle covers a large extent of the PV perimeter, there are specific breakthroughs from the left atrium that allow ostial PV disconnection by use of partial perimetric ablation.