Organized left atrial tachyarrhythmia during stepwise linear ablation for atrial fibrillation.
BACKGROUND
This study attempted to delineate the mechanism of organized left atrial tachyarrhythmia (AT) during stepwise linear ablation for atrial fibrillation (AF) using noncontact mapping.


RESULTS
Eighty patients in whom organized ATs developed or induced during stepwise linear ablation for AF were enrolled. Left atrial (LA) activation during ATs was mapped using noncontact mapping. Radiofrequency (RF) energy was delivered to the earliest activation site or narrowest part of the reentrant circuit of ATs. A total of 146 ATs were mapped. Four ATs were characterized as a focal mechanism (cycle length (CL): 225 +/- 49 ms). A macroreentrant mechanism was confirmed in the remaining 142 ATs. LA activation time accounted for 100% of CL (205 +/- 37 ms). All 142 ATs used the conduction gaps in the basic figure-7 lesion line. There were three types of circuits classified based on the gap location. Type I (n = 68) used gaps at the ridge between left atrial appendage (LAA) and left superior pulmonary vein (LSPV). Type II (n = 50) used gaps on the LA roof. Type III (n = 24) passed through gaps in the mitral isthmus. Ablation at these gaps eliminated 130 ATs. During the follow-up period of 16.2 +/- 6.7 months, 82.5% of the 80 patients were in sinus rhythm.


CONCLUSIONS
The majority of left ATs developed during stepwise linear ablation for AF are macroreentrant through conduction gaps in the figure-7 lesion line, especially at the LAA-LSPV ridge. Noncontact activation mapping can identify these gaps accurately and quickly to target effective catheter ablation.
Zheng
Lihui
L
Clinical EP Laboratory and Arrhythmia Center, Fuwai Hospital and Cardiovascular Institute, Peking Union Medical College (PUMC)-Chinese Academy of Medical Sciences (CAMS), Beijing, China.
Yao
Yan
Y
Zhang
Shu
S
Chen
Wensheng
W
Zhang
Kuijun
K
Wang
Fangzheng
F
Chen
Xin
X
He
Ding Sheng
DS
Kadish
Alan H
AH
D001281:Atrial Fibrillation / Q000150:complications / Q000601:surgery*; D018780:Body Surface Potential Mapping / Q000379:methods*; D017115:Catheter Ablation / Q000009:adverse effects / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013612:Tachycardia, Ectopic Atrial / Q000209:etiology* / Q000517:prevention & control*; D016896:Treatment Outcome