Maximizing the Effectiveness of Ablation for Arrhythmias in the Congenital Heart Patients

Use of contact force technology for cardiac arrhythmia ablation in children

Background

New techniques for cardiac arrhythmia ablation, such as contact force (CF) technology, have emerged recently. These catheters provide information about adequate tissue contact for optimal lesions. In adults, these techniques have shown greater accuracy, reduced arrhythmia recurrence and complications, and higher success rates. However, data on pediatric patients are limited.

Objective

The purpose of this study was to describe the experience with arrhythmia ablation using CF catheters in the pediatric population.

Methods

A retrospective cross-sectional descriptive study of all patients <18 years old undergoing cardiac 3-dimensional mapping and ablation with CF between March 2016 and June 2022 was performed.

Results

A total of 321 patients were included (51.40% male; mean age 12.26 years). The most frequent arrhythmia were supraventricular tachycardia (SVT) mediated by accessory pathways (APs) (atrioventricular reentrant tachycardia in 82.24%, ventricular arrhythmia in 11.21%, atrial tachycardia in 5.92%). Mean procedural time was 2.86 ± 1.2 hours, and average contact used was 14.33g ± 6.88g. The success rate of ablation was 97.82% with a low risk of complications.

Conclusion

This is the largest published series of CF technology use in patients <18 years old. In the pediatric population, CF ablation is a safe procedure with high success rates and can be used for most arrhythmic substrates. The most frequent tachycardia observed in this study was SVT mediated by APs. Contact with 14g is safe and yields an excellent outcome in children. The presence of structural heart anomalies and previous ablation procedures decreased the success rate.

Missing pouches in high-density mapping of atrial tachyarrhythmia in congenital heart diseases

BACKGROUND

The use of high-density electroanatomical mapping in the Chinese population for congenital heart disease (CHD) is not well reported.

METHODS

Retrospective review of consecutive transcatheter ablation of atrial tachyarrhythmia using high-density mapping for CHD patients (at least moderate complexity) in the only tertiary congenital heart center in the territory from January 2017 to January 2019 was conducted. Orion mapping catheter in Rhythmia system (Boston Scientific) was used to create activation and voltage maps. Parameters including mechanism of arrhythmia, acute success, and follow-up data were recorded.

RESULTS

Eight patients were identified (median age 35.5 years) who underwent transcatheter ablation of atrial arrhythmia. More than one reentry circuits of IART were identified in five patients. It took a median of 32.4 minutes with 15,952 (IQR 13,395-18,530) mapping points per map. Cavo-annulus isthmus-dependent mechanism was the predominant reentry mechanism. Acute success with the elimination of all inducible tachycardia was achieved in six patients (75%), and partial success in two patients. There was recurrence of atrial arrhythmia in four patients (50%), in which three patients could be maintained in sinus rhythm with low-dose antiarrhythmic medication. Targeted substrate ablation was performed in six patients with multiple IART circuits. Critical anatomical pouches were identified in three patients, which were missed in the initial mapping using Orion basket mapping catheter.

CONCLUSIONS

High acute success rate of atrial arrhythmia ablation can be achieved using high-density anatomical mapping in CHD. Substrate ablation was required with multiple IART circuits identified. Vigilance should be sought to identify anatomical pouches.