Published Online
on March 6, 2009

A more recent version of this article appeared on June 1, 2009

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Original Article

Spatiotemporal Organization of the Left Atrial Substrate after Circumferential Pulmonary Vein Isolation of Atrial Fibrillation

Yenn-Jiang Lin¹; Ching-Tai Tai²; Tsair Kao³; Shih-Lin Chang²; Li-Wei Lo³; Ta-Chuan Tuan³; Ameya R. Udyavar³; Wongcharoen Wanwarang²; Yu-Feng Hu⁴; Han-Wen Tso³; Wen-Chin Tsai²; Chien-Jung Chang²; Kuo-Chang Ueng⁵; Satoshi Higa⁶ and Shih-Ann Chen^1,7

¹ Taipei Veterans General Hospital and National Yang-Ming University;
² Taipei Veterans General Hospital;
³ National Yang-Ming University;
⁴ Taipei Medical University Hospital;
⁵ Chung Shan Medical University;
⁶ University of the Ryukyus, Okinawa

⁷ E-mail: epsachen{at}ms41.hinet.net

Background—There is a paucity of data regarding the mechanism of maintaining atrial fibrillation (AF) post pulmonary vein isolation (PVI) in AF patients. The aim of this study was to examine the impact of circumferential PVI on the left atrial (LA) substrate characteristics.

Methods and Results—Seventy-two AF patients (53±11 y/o) underwent mapping and catheter ablation using a NavX system. The bi-atrial characteristics such as the complex fractionated atrial electrograms (CFEs; based on fractionated intervals, FIs) and frequency analysis (based on dominant frequencies, DF) were mapped before and after PVI. PVI with electric isolation was performed in all patients. In the 45 patients who did not respond to PVI, the continuous CFEs (> 8 seconds, 18±18% and 12±17% of the LA sites, before and after PVI, respectively, P=0.02), degree of LA fractionation (mean FI: 75.6±14.3msec vs. 87.3±16.7msec, P=0.001), and mean LA DF (6.92±0.88Hz vs. 6.58±0.91Hz, P=0.001) decreased after PVI. Complete PVI altered the distribution of the CFEs toward the LA anteroseptum, mitral annulus, and LA appendage regions. A persistent presence of continuous CFEs in the vicinity of the DF sites (observed in 53% patients) correlated with a higher procedural AF termination rate for the CFE ablation (63% vs. 23%, P<0.05).

Conclusions—Complete PVI eliminated some CFEs in the LA and altered the distribution of the CFEs. The persistent presence of CFEs before and after PVI in the vicinity of the high frequency sites is important for AF maintenance after PVI.

Key Words: ablation • mapping • atrial fibrillation • electrogram • frequency analysis