OBJECTIVEThe study was undertaken to analyze retrospectively the results of radiofrequency catheter ablation (RFCA) on septum originated tachycardia in children with arrhythmia. The 98 children were all treated with RFCA on septum originated tachycardia in which the ablation sites were located near the bundle of His.

METHODSFifty female and forty-eight male cases were included in this analysis. They were at the age of 8.1 +/- 2.3 years and their body weight was (28 +/- 9) kg. The arrhythmia they suffered from consisted of atrioventricular nodal reentry tachycardia (AVNRT) (n = 62), atrioventricular reentry tachycardia (AVRT) on septum (n = 25), atria Itachycardia on Koch areas (n = 3) and left ventricular tachycardia (ILVT) on the septum (n = 8). Swartz SRO long sheath was used on the right site ablation. Titration of capacity and degreed time of increase were used in the ablation.

RESULTSRadiofrequency ablation was successful in all cases. Eleven cases had relapse after the procedure. They accepted RFCA again and then the treatment succeeded. One case of AVRT at the posterior septum experienced complete atrioventricular block (AVB) during ablation. Two weeks later this case was implanted with permanent pacemaker.

CONCLUSIONSThe septal site is narrow and small in children. Atrioventricular node is tender. If the above facts were neglected, it was very likely to cause AVB, especially in children accepting the procedures of electrophysiologic study an RFCA on the septal site. Attention should be paid to the followings during such procedures: ablation in the sinus rhythm; ablation following the principle, titration of capacity and degreed time of increase; ablation at the right site long sheath; thermo-ablation catheter application and ablation on the two sides of septum in the posterior septum ablation procedure. The end-point of ablation in children should be the elimination of tachycardia and the delta wave, disassociation of VA or passing through bundle of His at pacing in the ventricle, disappearance of jumping conduction or no echo or one echo but without AVNRT after infusion of isoprenaline and stimulation procedure. Avoiding bundle of His injury is important during the procedure of ablation in children.