Focal atrial tachycardias arising from the right atrial appendage: electrocardiographic and electrophysiologic characteristics and radiofrequency ablation.
OBJECTIVE
To characterize the electrocardiographic and electrophysiological features and frequency of focal atrial tachycardia (AT) originating from the right atrial appendage (RAA).


BACKGROUND
The RAA has been described as a site of origin of AT, but detailed characterization of these tachycardias is limited.


METHODS
Ten patients (3.8%) of 261 undergoing radiofrequency ablation (RFA) for focal AT are reported. Endocardial activation maps (EAM) were recorded from catheters at the CS (10 pole), tricuspid annulus (20 pole Halo catheter), and His positions. P waves were classified as negative, positive, isoelectric, or biphasic.


RESULTS
The mean age was 39 +/- 20 years, nine males, with symptoms for 4.1 +/- 5.1 years. Tachycardia was incessant in seven patients, spontaneous in one patient, and induced by programmed extrastimuli in two patients. These foci had a characteristic P wave morphology. The P wave was negative in lead V(1) in all patients, becoming progressively positive across the precordial leads. The P waves in the inferior leads were low amplitude positive in the majority of patients. Earliest EAM activity occurred on the Halo catheter in all patients. Mean activation time at the successful RFA site =-38 +/- 15 msec. Irrigated catheters were used in six patients, due to difficulty achieving adequate power. RFA was acutely successful in all patients. Long-term success was achieved in all patients over a mean follow up of 8 +/- 7 months.


CONCLUSIONS
The RAA is an uncommon site of origin for focal AT (3.8%). It can be suspected as a potential anatomic site of AT origin from the characteristic P wave and activation timing. Irrigated ablation catheters are often required for successful ablation. Long-term success was achieved with focal ablation in all patients.
Roberts-Thomson
Kurt C
KC
Department of Cardiology, Royal Melbourne Hospital, Melbourne, Australia.
Kistler
Peter M
PM
Haqqani
Haris M
HM
McGavigan
Andrew D
AD
Hillock
Richard J
RJ
Stevenson
Irene H
IH
Morton
Joseph B
JB
Vohra
Jitendra K
JK
Sparks
Paul B
PB
Kalman
Jonathan M
JM
D000328:Adult; D000368:Aged; D020517:Atrial Appendage / Q000503:physiopathology / Q000601:surgery*; D001282:Atrial Flutter / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods; D004562:Electrocardiography / Q000379:methods; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria; D006801:Humans; D008297:Male; D008875:Middle Aged; D013610:Tachycardia / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome