The most common site of success and its predictors in radiofrequency catheter ablation of the slow atrioventricular nodal pathway in children.
BACKGROUND
Locating ablation targets on the slow pathway in children as one would in adults may not accommodate the dimensional changes of Koch's triangle that occur with heart growth. We investigated the most common site of success and the effect of a variety of variables on the outcome of slow pathway ablation in children.


METHODS
A total of 116 patients (ages 4-16 years) with structurally normal hearts underwent radiofrequency ablation of either the antegrade or the retrograde slow pathway. Ablation sites were divided into eight regions (A1, A2, M1, M2, P1, P2, CS1, and CS2) at the septal tricuspid annulus.


RESULTS
Ablation was successful in 112 (97%) children. The most common successful ablation sites were at the P1 region. The less the patient weighed, the more posteriorly the successful site was located (P = 0.023, OR 0.970, 95% CI 0.946-0.996), and the more likely the slow pathway was eliminated rather than modified: median weight was 46.7 kg (range, 14.5-94.3 kg) in the eliminated group and 56.5 kg (range, 20-82.6 kg) in the modified group (P = 0.021, OR 1.039, 95% CI 1.006-1.073).


CONCLUSIONS
The most common site of success for slow pathway ablation in children is at the P1 region of the tricuspid annulus. The successful sites in lighter children are more posteriorly located. Weight is also a predictor of whether the slow pathway is eliminated or only modified.
Hwang
Haw-Kwei
HK
Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan.
Wolff
Grace S
GS
Sun
Fang-Ju
FJ
Young
Ming-Lon
ML
D000293:Adolescent; D001283:Atrioventricular Node / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis* / Q000601:surgery*; D016896:Treatment Outcome