Catheter ablation of accessory atrioventricular pathways in children and adolescents - weight matters

Paroxysmal supraventricular tachycardias are the most common heart rhythm disorders in children and adolescents with accessory atrioventricular pathways (AP) as the most frequent substrate. Aim of this study was to assess the impact of body weight on effectiveness and safety of catheter ablation.

Since 10/2002, 321 ablation procedures of APs have been performed in our institution. Median body weight was 44 kg (6.5-114 kg) with 20 patients < 15 kg. Congenital heart defects were present in 29 patients (11%).

AP localization was around the tricuspid valve annulus in 41%, around the mitral valve annulus in 44% and epicardial in 4%. Multiple APs were present in 11%. Median procedure time was (patients <15 kg / >15 kg) 261/190 min (p<0.001), fluoroscopy time was 22.3/14.5 min (p<0.001). A median of 7/11 lesions were applied (p=0.05). Acute procedural success rate was lower in children < 15kg (85/89%, p<0.01). Major complications were noticed in 5/321 (1.6%) ablation procedures: complete AV block 1/321, major vessel complications 3/321 and thrombosis of a coronary artery 1/321. Major complication rate was significantly higher in patients < 15 kg (2/20 vs. 3/301; p<0.01).

Catheter ablation was a safe and effective treatment of APs in children and adolescents. Procedural duration, fluoroscopy time, lesion number, and major complication rate were significantly higher in children <15 kg. Whenever possible, ablation procedures should be postponed until children reached a body weight above 15 kg.