Atrial tachycardias originating from the atrial septum: electrophysiologic characteristics and radiofrequency ablation.
BACKGROUND
The characteristics of atrial tachycardia (AT) have varied widely among different reports. The anatomic locations of ATs may bias the results. We propose that septal ATs and free-wall ATs have different characteristics.


RESULTS
One hundred forty-one patients with AT underwent electropharmacologic study, endocardial mapping, and radiofrequency ablation. Forty-nine (34.7%) patients had septal AT originating from the anteroseptal, mid-septal, and posteroseptal areas. Tachycardia cycle length was similar between septal AT and free-wall AT (367 +/- 46 msec vs 366 +/- 58 msec, P > 0.05). More patients with septal AT required isoproterenol to facilitate induction (44.9% vs 31.5%, P <.0.05). Septal AT was more sensitive to adenosine than free-wall AT (84.4% vs 67.8%, P < 0.05). Only posteroseptal AT showed a positive P wave in lead V1 and negative P wave in all the inferior leads (II, III, aVF). Radiofrequency catheter ablation had a comparable success rate for septal AT and free-wall AT (96% vs 95%) without impairment of AV conduction. During follow-up of 49 +/- 13 months (range 17 to 85), the recurrence rate was similar for septal AT and free-wall AT (3.2% vs 4.6%, P = 0.08).


CONCLUSIONS
Septal AT has electrophysiologic characteristics that are distinct from those of free-wall AT. Catheter ablation of the septal AT is safe and effective.
Division of Cardiology, National Yang-Ming University, School of Medicine, and Taipei Veterans General Hospital, Taiwan, Republic of China.
C C
CC
Chen
C T
CT
Tai
C E
CE
Chiang
W C
WC
Yu
S H
SH
Lee
Y J
YJ
Chen
M H
MH
Hsieh
C F
CF
Tsai
K W
KW
Lee
Y A
YA
Ding
M S
MS
Chang
S A
SA
Chen
D000328:Adult; D000368:Aged; D017115:Catheter Ablation; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D013610:Tachycardia / Q000503:physiopathology* / Q000601:surgery