Unipolar electrogram in identification of successful targets for radiofrequency catheter ablation of focal atrial tachycardia.
OBJECTIVE
To analyze the unipolar electrogram from successful and unsuccessful ablation sites of focal atrial tachycardia (AT), and to evaluate its value in the identification of successful targets.


METHODS
Fifteen consecutive patients with focal AT were referred for radiofrequency catheter ablation (RFCA). Both unipolar (from the tip electrode of ablating catheter) and bipolar (from the distal pair of electrode of ablating catheter) electrograms were used to identify the ablation targets of focal AT.


RESULTS
Successful ablation was echieved in 14 patients. Radiofrequency energy was delivered at a total of 27 sites. The bipolar electrograms associated with successful ablation sites showed earlier atrial deflection relative to P wave onset (36 ms +/- 15 ms vs 30 ms +/- 11 ms, P < 0.05) than the electrograms associated with failed ablation sites. At the 14 successful ablation sites, the unipolar electrograms displayed a completely negative atrial wave ("QS" morphology) beginning with intrinsic deflection. However, at the 13 unsuccessful ablation sites, a "rS" morphology of atrial wave was shown on the unipolar electrogram.


CONCLUSIONS
The "QS" morphology of the atrial wave on unipolar electrograms appears to represent a reliable marker for identifying the successful ablation targets of focal AT, with a high sensitivity and specificity.
Department of Clinical Electrophysiology, Fuwai Hospital, CAMS and PUMC, Beijing 100037, China. tangkai934@sohu.com
Kai
K
Tang
Jian
J
Ma
Shu
S
Zhang
Jianmin
J
Chu
Fangzheng
F
Wang
Kuijun
K
Zhang
Xin
X
Chen
D000293:Adolescent; D000328:Adult; D000368:Aged; D017115:Catheter Ablation / Q000379:methods*; D002648:Child; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013610:Tachycardia / Q000175:diagnosis / Q000601:surgery*