The challenge of transseptal access for catheter ablation of left-sided arrhythmia substrate in infants and small children under 6 years of age

Abstract

Abstract Background Young age and small cardiac dimensions are increased risk factors for catheter ablation (CA), therefore ablation below 15 kg should be recommended only in selected drug-refractory cases. The need for a transseptal puncture (TSP) may be an additional risk factor. Persistent foramen ovale (PFO) in infants can mitigate this risk and paradoxically, decrease the complication rate in the very young. Purpose This study aimed to compare the results of left-sided CA in infants under 1 year and in children between 1-6 years of age. Methods Between January 2010 and September 2023, 1703 pediatric CAs were performed, of which 17 left-sided ablations in children under 6 years without structural heart disease were retrospectively evaluated. CA results below 1 year and between 1-6 years of age were compared in terms of body size, procedural parameters, left atrial (LA) access, complication, and success rate. Results The patient group below 1 year (Group 1, n=5) has a mean age=0.13±0.03 years, mean body weight=3.6±1.1 kg, mean height=52.3±3.6 cm. Patients between 1-6 years (Group 2, n=12) have mean age=5.0±1.1 years, mean body weight=17.9±2.2 kg, mean height=111.2±7.4 cm. The arrhythmia substrate was an overt pathway in 3 pts (17.6%), concealed accessory pathway in 7 pts (41.2%), and focal LA tachycardia in 7 pts (41.2%). Foramen ovale was persistent in all 5 children in Group 1 and TSP was not required. In Group 2, only 2 pts (16.7%) had PFO, and, all other procedures required TSP. TSP was successful in 9/10 cases (90%). No complications related to LA access or other adverse events occurred in Group 1. In Group 2, there was one case of pericardial effusion that spontaneously regressed and one case of mechanical-induced advanced AV block that resolved after six days. There were no significant differences in procedure time, fluoroscopic time, and radiation dose between the two groups (Group 1: 126.4±47.0 min, 6.4±4.5 min, 4.0±5.3 cGycm2 vs. Group 2: 162.6±49.2 min, 7.9±9.4 min, 9.0±12.4 cGycm2, p>0.05). All CAs were performed with RF energy. The acute success rate of the procedures was 100%. Conclusion CA of left-sided arrhythmias in infants and small children may offer a safe and effective therapeutic option in selected cases. The high prevalence of PFO may explain the paradoxically less complication under 1 year of age.