Use of cryoablation for treatment of tachyarrhythmias in 2010: survey of current practices of pediatric electrophysiologists

Zero-Fluoroscopy Catheter Ablation of Supraventricular Tachycardias in the Pediatric Population

Catheter ablation (CA) of supraventricular tachycardias (SVTs) is conventionally performed with the aid of X-ray fluoroscopy. Usage of a three-dimensional (3D) electro-anatomical mapping (EAM) system and intracardiac echocardiography (ICE) enables zero-fluoroscopy ablation, eliminating the harmful effects of radiation. We retrospectively analyzed the feasibility, effectiveness and safety of zero-fluoroscopy radiofrequency and cryoablation of various types of SVTs in pediatric patients. Overall, in 171 consecutive patients (12.5 ± 3.9 years), 175 SVTs were diagnosed and 201 procedures were performed. The procedural success rate was 98% (193/197), or more precisely, 100% (86/86) for AVNRT, 95.8% (91/95) for AVRT, 94.1% (16/17) for AT and 100% (2/2) for AFL. No complications were recorded. Follow-up was complete in 100% (171/171) of patients. During the mean follow-up period of 488.4 ± 409.5 days, 98.2% of patients were arrhythmia-free with long-term success rates of 98.7% (78/79), 97.5% (78/80), 100% (13/13) and 100% (2/2) for AVNRT, AVRT, AT and AFL, respectively. Zero-fluoroscopy CA of various types of SVTs in the pediatric population is a feasible, effective and safe treatment option.

Remote magnetic navigation shows superior long-term outcomes in pediatric atrioventricular (nodal) tachycardia ablation compared to manual radiofrequency and cryoablation

Background

Catheter ablation (CA) is the first-choice treatment for tachyarrhythmia in children. Currently available CA techniques differ in mechanism of catheter navigation and energy sources. There are no large studies comparing long-term outcomes between available CA techniques in a pediatric population with atrioventricular reentry tachycardia (AVRT) or atrioventricular nodal reentry tachycardia (AVNRT) mechanisms.

Objective

This study aimed to compare procedural and long-term outcomes of remote magnetic navigation-guided radiofrequency (RF) ablation (RMN), manual-guided RF ablation (MAN) and manual-guided cryoablation (CRYO).

Methods

This single-center, retrospective study included all first consecutive CA procedures for AVRT or AVNRT performed in children without structural heart disease from 2008 to 2019. Three study groups were defined by the ablation technique used: RMN, MAN or CRYO. Primary outcome was long-term recurrence of tachyarrhythmia.

Results

In total, we included 223 patients, aged 14 (IQR 12-16) years; weighting 56 (IQR 47-65) kilograms. In total, 108 procedures were performed using RMN, 76 using MAN and 39 using CRYO. RMN had significantly lower recurrence rates compared to MAN and CRYO at mean follow-up of 5.5 ± 2.9 years (AVRT: 4.3% versus 15.6% versus 54.5%, P < 0.001; AVNRT: 7.7% versus 8.3% versus 35.7%, P = 0.008; for RMN versus MAN versus CRYO respectively). In AVNRT ablation, RMN had significantly lower fluoroscopy doses compared to CRYO [30 (IQR 20-41) versus 45 (IQR 29-65) mGy, P = 0.040).

Conclusion

In pediatric patients without structural heart disease who underwent their first AV(N)RT ablation, RMN has superior long-term outcomes compared to MAN and CRYO, in addition to favorable fluoroscopy doses.

Pediatric catheter ablation at the beginning of the 21st century: results from the European Multicenter Pediatric Catheter Ablation Registry 'EUROPA'

AIMS

Contemporary data from prospective multicentre registries on catheter ablation in pediatric patients are sparse. Aim of the European Pediatric Catheter Ablation Registry EUROPA was to contribute data to fill this gap of knowledge.

METHODS AND RESULTS

From July 2012 to June 2017, data on catheter ablation in pediatric patients (≤18 years of age) including a 1-year follow-up from five European pediatric EP centres were collected prospectively. A total of 683 patients (mean age 12.4 ± 3.9 years, mean body weight 50.2 ± 19 kg) were enrolled. Target tachycardia was WPW/atrioventricular-nodal re-entrant tachycardia (AVRT) in 380 (55.7%) patients, AVNRT in 230 (33.8%) patients, ventricular tachycardia (VT) in 24 (3.5) patients, focal atrial tachycardia (FAT) in 20 (2.9%) patients, IART in 14 (2%) patients, and junctional ectopic tachycardia in 3 (0.45) patients. Overall procedural success was 95.6%. Compared with all other substrates, success was significantly lower in FAT patients (80%, n = 16, P = 0.001). Mean procedure duration was 136 ± 67 min and mean fluoroscopy time was 4.9 ± 6.8 min. Major complications occurred in 0.7% of the patients. No persisting AV block requiring permanent pacing was reported. At 1-year follow-up (605/683 patients, 95%), tachycardia recurrence was reported in 7.8% of patients. Recurrence after VT ablation (33%) was significantly higher (P = 0.001) than after ablation of all other substrates.

CONCLUSION

The present study proves overall high efficacy and safety of catheter ablation of various tachycardia substrates in pediatric patients. Of note, complication rate was exceptionally low. Long-term success was high except for patients after VT ablation.

Current status of pediatric electrophysiology in Latin America: a LAHRS survey

PURPOSE

Over the last years, pediatric electrophysiology (EP) has evolved as a consolidated subspecialty of pediatric cardiology. In the USA, Canada, and Europe, there is a clear picture of the status of pediatric EP, but the situation in Latin America is largely unknown.

METHODS

A descriptive cross-sectional observational study was performed. A survey was conducted by the Latin American Heart Rhythm Society in Spanish and Portuguese to assess the status of development of pediatric EP across Latin American countries.

RESULTS

There are physicians practicing pediatric EP in 11 Latin American countries. The scope of the practices includes clinical and non-invasive EP as well as performing invasive EP procedures. All the current pediatric EP interventions are performed in most of Latin American countries.

CONCLUSIONS

Pediatric electrophysiology is present as a subspecialty in half of the countries in Latin America, and all the current electrophysiology procedures and therapeutic technologies are available in most Latin American countries.

Opportunities for Regulatory Changes to Promote Pediatric Device Innovation in the United States: Joint Recommendations From Pediatric Innovator Roundtables

Objective: The purpose of this report is to provide insight from pediatric stakeholders with a shared desire to facilitate a revision of the current United States regulatory pathways for the development of pediatric healthcare devices. Methods: On August 5, 2020, a group of innovators, engineers, professors and clinicians met to discuss challenges and opportunities for the development of new medical devices for pediatric health and the importance of creating a regulatory environment that encourages and accelerates the research and development of such devices. On January 6, 2021, this group joined regulatory experts at a follow-up meeting. Results: One of the primary issues identified was the need to present decision-makers with opportunities that change the return-on-investment balance between adult and pediatric devices to promote investment in pediatric devices. Discussion/Conclusion: Several proposed strategies were discussed, and these strategies can be divided into two broad categories: 1. Removal of real and perceived barriers to pediatric device innovation; 2. Increasing incentives for pediatric device innovation.

Junctional ectopic tachycardia in infants and children

Tachyarrhythmias originating in the atrioventricular (AV) node and AV junction including the bundle of His complex (BH) are called junctional tachycardia (JT) or junctional ectopic tachycardia (JET). Congenital JET (CJET) is a rare arrhythmia that occurs in patients without a preceding cardiac surgery and can be refractory to medical therapy and associated with high morbidity and mortality. CJET has a high rate of morbidity and mortality with death occurring in 35% of cases. JET occurring within 72 hours after cardiac surgery is referred to as postoperative JET (POJET) and caused by direct trauma, ischemic, or stretch injury to the AV conduction tissues during surgical repair of congenital heart defects. Focal junctional tachycardia (FJT) is also known as automatic junctional tachycardia and includes paroxysmal or non-paroxysmal forms. We discuss a staged approach to therapy with improved pharmacological therapies and the use of catheter-based therapies.

Electrophysiology Study for Complex Supraventricular Tachycardia in Congenital Heart Disease Patients With Single-Ventricle Physiology

BACKGROUND

Supraventricular tachycardia (SVT) is common in complex congenital heart disease (CCHD) patients with single-ventricle physiology and may cause hemodynamic deterioration. We reported the outcomes of catheter ablation for such complex SVT in these single-ventricle CCHD patients.

METHODS AND RESULTS

Patients with single-ventricle physiology (defined as CCHD patients) who received electrophysiology studies and catheter ablation between 1995 and 2015 were studied. We enrolled 30 CCHD patients (18 with right atrial isomerism, 5 with left atrial isomerism, and 7 with other CCHDs; 17 male, 13 female). The age of onset of clinical SVT was 6.7 years (±4.7 years). Electrophysiology studies and ablation were performed at age 7.1 years (±3.9 years); body weight was 20.7 kg (±10.0 kg). Twin atrioventricular nodes were present in 60% of patients (right atrial isomerism, 72.2%; left atrial isomerism, 40%; other CCHDs, 42.9%). Manifested preexcitation was noted in 10% of patients. SVT was induced in 21 patients. Twin atrioventricular nodal reentrant tachycardia was the most common (57.1%), followed by atrioventricular reentrant tachycardia (28.6%), junctional tachycardia (14.3%), and atrioventricular nodal reentrant tachycardia (9.5%). Multiple arrhythmias were common (33.3%), particularly in patients with atrioventricular reentrant tachycardia (50%). Ablation successfully eliminated SVT in 12 of 14 patients (85.7%), with a recurrence rate of 16.7% during 6 years of follow-up.

CONCLUSIONS

Transcatheter ablation of complex SVT substrates, including minor atrioventricular node of twin atrioventricular nodal reentrant tachycardia, accessory pathways of atrioventricular reentrant tachycardia, and a slow pathway of atrioventricular nodal reentrant tachycardia, is effective in CCHD patients. The limitations are limited vascular access and the risk of atrioventricular block.

Cryoablation with an 8-mm-Tip Catheter for Right-Sided Accessory Pathways in Children

BACKGROUND

Cryoablation is increasingly utilized in children because of its safety profile. Recently, larger catheter tips have been more widely used to improve long-term success rates. The aim of this study was to assess the safety and efficacy of 8-mm-tip catheters for cryoablation of right-sided accessory pathways (APs) in children.

METHODS

Electrophysiological procedures were performed using the EnSite™ system (St. Jude Medical Inc., St. Paul, MN, USA).

RESULTS

Between July 2010 and July 2014, 54 patients (mean age: 13.1 ± 3.7 years) underwent cryoablation using an 8-mm-tip catheter. In 18 of 54 (33%) patients where an 8-mm-tip catheter was the first-choice catheter, the success rate was 18 of 18 (100%). There was a history of previous failed attempts or recurrence with radiofrequency ablation and/or 6-mm-tip cryoablation in 36 of 54 (67%) patients. The success rate in these patients was 24 of 36 (67%). No fluoroscopy was used in 34 of 54 procedures. The recurrence rate was six of 42 (14%) during a mean follow-up period of 32 ± 15 months. In one patient, transient atrioventricular block occurred.

CONCLUSIONS

Cryoablation with an 8-mm-tip catheter for right-sided APs in children who weigh over 40 kg appears to be safe and acutely effective in cases where conventional ablation methods fail and also as a first choice for ablation procedure. However, the recurrence rate still seems to be high.

Research accomplishments in pediatric electrophysiology: a historical review

Arrhythmia management in young patients plays a small but important role within the broader discipline of cardiac electrophysiology (EP). By virtue of its sharp focus on developmental cardiology, congenital heart defects, and hereditary channelopathies, pediatric EP has contributed in significant ways to improved understanding of rhythm disorders in patients of all ages. Scientific progress in the field was recently reviewed at the 2012 meeting of the Heart Rhythm Society, where historical details of pioneering investigations in pediatric EP were highlighted. In this article, we hope to summarize those details and acknowledge the roles of individuals and organizations that were instrumental in developing the subspecialty.

Accessory pathway ablation in a 6-year-old girl using remote magnetic navigation as an alternative to cryoablation

A 6-year-old girl with evidence of a parahisian accessory pathway on a baseline electrocardiogram underwent successful catheter ablation using magnetic navigation. Magnetic remote controlled ablation eliminated the parahisian pathway with the first radiofrequency application. A second anterolaterally located concealed pathway was successfully ablated in the same session, resulting in exclusively atrioventricular nodal conduction bidirectionally (total fluoroscopy, 4 min; 25 μGy).

[Wolff-Parkinson-White syndrome with a parahisian accessory pathway: the place of cryoablation]

The ablation of parahisian accessory pathways is a challenge because of the risk of atrioventricular block. In this observation, we describe the case of an eleven-year-old girl presenting a parahisian accessory pathway treated successfully by cryoablation. It is a pediatric case, in which, the accessory pathway and the nodo-hisian conduction pathway where superposed in anatomic and electrophysiological terms. Cryoablation should be the method of choice of ablation in pediatric patients.