The novel electrophysiology of complex fractionated atrial electrograms: insight from noncontact unipolar electrograms.
BACKGROUND
The noncontact mapping (NCM) system possesses the merit of global endocardial recording for unipolar and activation mapping.


OBJECTIVE
We aimed to evaluate the unipolar electrogram characteristics and activation pattern over the bipolar complex fractionated atrial electrogram (CFAE) sites during atrial fibrillation (AF).


METHODS
Twenty patients (age 55 +/- 11 years old, 15 males) who underwent NCM and ablation of AF (paroxysmal/persistent = 13/7) were included. Both contact bipolar (32-300 Hz) and NCM virtual unipolar electrograms (0.5-300 Hz) were simultaneously recorded along with the activation pattern (total 223 sites, 11 +/- 4 sites/patient). A CFAE was defined as a mean bipolar cycle length of <or= 120 ms with an intervening isoelectric interval of more than 50 ms (Group 1A, n = 63, rapid repetitive CFAEs) or continuous fractionated activity (Group 1B, n = 59, continuous fractionated CFAEs), measured over a 7.2-second duration. Group 2 consisted of those with a bipolar cycle length of more than 120 ms (n = 101).


RESULTS
The Group 1A CFAE sites exhibited a shorter unipolar electrogram cycle length (129 +/- 11 vs 164 +/- 20 ms, P < 0.001), and higher percentage of an S-wave predominant pattern (QS or rS wave, 63 +/- 13% vs 35 +/- 13%, P < 0.001) than the Group 2 non-CFAE sites. There was a linear correlation between the bipolar and unipolar cycle lengths (P < 0.001, R = 0.87). Most of the Group 1A CFAEs were located over arrhythmogenic pulmonary vein ostia or nonpulmonary vein ectopy with repetitive activations from those ectopies (62%) or the pivot points of the turning wavefronts (21%), whereas the Group 1B CFAEs exhibited a passive activation (44%) or slow conduction (31%).


CONCLUSIONS
The bipolar repetitive and continuous fractionated CFAEs represented different activation patterns. The former was associated with an S wave predominant unipolar morphology which may represent an important focus for maintaining AF.
Lo
Li-Wei
LW
Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.
Higa
Satoshi
S
Lin
Yenn-Jiang
YJ
Chang
Shih-Lin
SL
Tuan
Ta-Chuan
TC
Hu
Yu-Feng
YF
Tsai
Wen-Chin
WC
Tsao
Hsuan-Ming
HM
Tai
Ching-Tai
CT
Ishigaki
Sugako
S
Oyakawa
Asuka
A
Maeda
Minetaka
M
Suenari
Kazuyoshi
K
Chen
Shih-Ann
SA
D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000601:surgery*; D017115:Catheter Ablation / Q000295:instrumentation* / Q000379:methods*; D003627:Data Interpretation, Statistical; D004562:Electrocardiography / Q000295:instrumentation*; D004594:Electrophysiology; D005260:Female; D005500:Follow-Up Studies; D006321:Heart / Q000503:physiopathology; D006325:Heart Atria / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results