Radiofrequency Catheter Ablation of Accessory Atrioventricular Pathways in Infants and Toddlers ≤ 15 kg

Risk Stratification in Pediatric Wolff-Parkinson-White: Practice Variation Among Pediatric Cardiologists and Electrophysiologists

BACKGROUND

Published guidelines provide recommendations for risk stratification in pediatric Wolff-Parkinson-White (WPW). There are no data on provider concordance with these guidelines. We hypothesized that significant practice variation exists between pediatric cardiologists (PC) and electrophysiologists (EP).

METHOD

The records of all patients, age 8 to 21 years, with a new ECG diagnosis of WPW between 1/1/2013 and 12/31/2018, from a single center, were retrospectively reviewed. Subjects were categorized on the basis of symptoms and resting ECG findings as one of the following: asymptomatic intermittent WPW, asymptomatic persistent WPW, or symptomatic WPW. The performance and results of diagnostic testing, including Holter monitor, event monitor, exercise stress test (EST), and electrophysiology study (EPS), were recorded. The primary outcome was concordance with published guidelines. A secondary outcome was documentation of a discussion of sudden cardiac death (SCD) risk.

RESULTS

615 patient encounters were analyzed in 231 patients with newly diagnosed WPW pattern on ECG (56% male; mean age at diagnosis 13.9 ± 2.5 years). EP were observed to have a significantly higher rate of guideline concordance than PC (95% vs. 71%, p < 0.001). There was significant practice variation between PC and EP in the documentation of a discussion of SCD risk: 96% in EP vs. 39% in PC (p < 0.001).

CONCLUSION

Significant practice variation exists in the non-invasive and invasive risk stratification of pediatric WPW, with lower concordance to published guidelines amongst PC, when compared to EP. This report highlights the need to promote awareness of current WPW guidelines in the pediatric cardiology community at large.

Association of Weight With Ablation Outcomes in Pediatric Wolff-Parkinson-White: Analysis of the NCDR IMPACT Registry

BACKGROUND

Guidelines for electrophysiology study (EPS) and catheter ablation in Wolff-Parkinson-White (WPW) are age based, but size may be a more relevant factor in determination of outcomes.

OBJECTIVES

The goal of this study was to evaluate the association of patient weight with outcomes of catheter ablation for pediatric WPW.

METHODS

A multicenter retrospective cohort study was performed on children aged 1 to 21 years with WPW and first-time EPS from April 2016 to December 2019 recorded in the IMPACT (Improving Pediatric and Adult Congenital Treatment) registry, excluding those with congenital heart disease, cardiomyopathy, and >1 ablation target. A weight threshold of 30 kg was selected, representing 1 SD below the cohort mean. The primary outcome was major adverse events (MAEs); additional outcomes included deferred ablation, use of cryoablation, and ablation success.

RESULTS

A total of 4,456 subjects from 84 centers were evaluated, with 14% weighing <30 kg. Subjects weighing <30 kg were more likely to have preprocedural supraventricular tachycardia (45% vs 29%; P < 0.001) and less likely to have right septal accessory pathways (25% vs 33%; P < 0.001). MAEs were rare, although with higher incidence in the <30 kg cohort (0.3% vs 0.05%; P = 0.04). No difference was seen in likelihood of deferred ablation (9% vs 12%; P = 0.07) or use of cryoablation (11% vs 11%; P = 0.70). Success was higher in the <30 kg cohort: 95% vs 92% (P = 0.009). This effect persisted after adjusting for covariates (odds ratio: 1.6; 95% CI: 1.01-2.70; P = 0.046).

CONCLUSIONS

Weight <30 kg was associated with a small but elevated risk of MAEs. Rates of deferred ablation and cryoablation were similar. Adjusting for factors (including accessory pathway type and location), weight <30 kg remained an independent predictor of acute success.

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.

Fluoroless catheter ablation of accessory pathways in adult and pediatric patients: a single centre experience

Catheter radio-frequency ablation (RFA) and cryo-ablation (CRA) procedures are an effective and safe treatment options for adult and pediatric patients with accessory pathway (AP) mediated tachycardias. Non-fluoroscopic techniques during catheter ablation (CA) procedures reduce potentially harmful effects of radiation. Our aim was to investigate the efficacy and safety of completely fluoroless RFA and CRA procedures in pediatric and adult patients with APs. Consecutive patients with AP-related tachycardia and high risk asymptomatic ventricular pre-excitation were assessed in retrospective analysis. Three-dimensional (3D) electro-anatomical mapping (EAM) and intra-cardiac echocardiography (ICE) were used as principal imaging modalities. Fluoroscopy was not used during any stage of the procedures. Among 116 included patients (22.76 ± 16.1 years, 68 patients < 19 years), 60 had left-sided APs, 16 right-sided APs and 40 septal APs. Altogether, 96 had RFA and 20 CRA procedures. The acute success rates (ASR) of RFA and CRA were 97.9% and 95%, respectively (p = 0.43), with recurrence rates (RR) of 8.33% and 40%, respectively (p < 0.0001). The outcome difference was principally driven by lower RR with RFA in septal APs (9.1% vs. 38.9%, p = 0.025). Pediatric patients with APs (12.21 ± 3.76 years) had similar procedural parameters and outcomes compared to adult patients. There were no procedure-related complications. In adult and pediatric patients with AP-related tachycardias, both CRA and RFA can be effectively and safely performed without the use of fluoroscopy. In addition, RFA resulted in better outcomes compared to CRA.

Ablation in Pediatric Patients and in Association with Congenital Heart Disease

Transcatheter ablation (TA) for treatment of pediatric tachyarrhythmias was first introduced in the early 1990s. Since then, its use as an alternative to antiarrhythmic drugs to treat supraventricular tachycardias caused by accessory pathway has been increasing. Nowadays, TA can be performed with high success rates and low complication rates even in very young children. Recently, the use of different types of energy (radiofrequency and cryoenergy), special ablation catheters, and 3D nonfluoroscopic mapping systems equipped with high technological tools has further improved safety and efficacy of TA, especially in difficult substrates and in patients with congenital heart disease.

Long-Term Follow-Up After Radiofrequency Catheter Ablation of Accessory Atrioventricular Pathways in Children

OBJECTIVES

The purpose of this study was to evaluate long-term safety and efficacy of catheter ablation of accessory atrioventricular pathways (AP) in a pediatric cohort.

BACKGROUND

Radiofrequency catheter ablation of accessory AP is the recommended treatment for patients with atrioventricular re-entrant tachycardia. Data on long-term results ≥1 year after AP ablation in pediatric patients is sparse.

METHODS

A total of 296 patients <18 years of age who had undergone radiofrequency-AP ablation between October 2002 and June 2015 were included into the study. Follow-up was >1 year in all patients. Median age at ablation had been 11.6 years, and median follow-up was 5.6 years. Recurrence of AP conduction after ablation was defined as documentation of pre-excitation, supraventricular tachycardia attributable to AP, or proof of AP conduction during repeat electrophysiological study.

RESULTS

AP ablation succeeded in 268 of 296 individuals (91%). After successful ablation, recurrence of AP conduction was observed in 29 of 268 individuals (10.8%). Of those 29, 23 (79%) had AP recurrence within the first year after ablation, whereas 13 (45%) had recurrence of AP conduction already within the first month. Six patients had late recurrence of AP conduction >1 year post-ablation. Procedural success and freedom from AP conduction after a single ablation procedure was 86% at 1 month, 83% at 1 year, and 81% at 5 years after ablation.

CONCLUSIONS

After radiofrequency ablation of AP in children, recurrence of AP conduction occurred in 23 subjects (8% of the study cohort) within the first year after ablation. Late recurrences >1 year after ablation were noticed in 6 children (2% of the study group), highlighting the need for longer follow-up >1 year. Results of the present study on late AP recurrence should be taken into account whenever families are counselled for pediatric AP ablation.

Catheter ablation of left-sided accessory pathways in small children

BACKGROUND

Accessory pathways (APs) are a common reason for supraventricular tachycardia in small children. Trans-septal puncture (TSP) approach is commonly used for the ablation of left-sided APs, however it may be challenging in small children. The aim of this study was to assess the efficacy and safety of trans-septal approach radiofrequency (RF) ablation of left-sided APs in children weighing up to 30 kg.

METHODS

Of the 658 children who underwent catheter ablation of APs since 06/2002, 86 children had left-sided AP and weighed less than 30 kg. TSP approach guided with TEE and fluoroscopy was used for left atrium access.

RESULTS

The mean age, height, and body weight were 7.6 ± 1.9 years, 122.4 ± 9.3 cm and 24.0 ± 4.2 kg, respectively. Forty-three children (50%) were male, 46 of 86 (53%) had manifest AP, 17 of 86 (20%) weighed less than 20 kg and in 24 of 86 children (28%) a three-dimensional system (3DS) was used to reduce fluoroscopy time. The acute success rate was 98.8% (85/86), with a recurrence rate of 2.4% (2/85) in a mean follow-up of 66.2 ± 42.7 (9.1-184.2) months. The mean procedure time and fluoroscopy time were significantly lower for the 3DS group compared to the standard fluoroscopy group 131 ± 41 (55-262) and 2.4 ± 1.5 (1-6) minutes vs 164 ± 51 (62-249) and 27 ± 13 (8-77) minutes, P < 0.01 and P < 0.0001, respectively. There were no ablation-related complications.

CONCLUSIONS

RF ablation of left-sided APs using TSP approach in small children had an excellent efficacy and safety profile. The use of 3DS significantly reduces the procedure and fluoroscopy time.

Double cryoenergy application (freeze-thaw-freeze) at growing myocardium: Lesion volume and effects on coronary arteries late after energy application. Implications for efficacy and safety in pediatric patients

INTRODUCTION

Cryoenergy is accepted as an alternative to radiofrequency ablation (RFA) in childen for ablation of supraventricular tachycardia substrates. Single cryoenergy application has been shown to be inferior to RFA. Double cryoenergy application has therefore been introduced into clinical practice, but experience concerning efficacy is limited. Coronary artery stenosis has been reported as serious complication after RFA for arrhythmia substrates but not after single cryoablation. The purpose of the study was to assess lesion volume (efficacy) and risk of coronary artery damage (safety), late, that is, 6 months, after double cryoenergy application in a piglet model.

METHODS

Two sequential cycles of cryoenergy were delivered at -75°C for 4 minutes at the atrioventricular groove in five piglets. Animals were restudied after 6 months by coronary angiography and intracoronary ultrasound (ICUS). Ablation lesions were examined histologically and lesion volume was determined by three-dimensional morphometric analysis.

RESULTS

Cryolesion volume was 174.04 ± 67.18 mm³ for atrial and 238.69 ± 112.1 mm³ for ventricular lesions (P > .05). Ventricular lesions, 4.06 ± 1.05 mm, were significantly deeper than atrial lesions, 3.58 ± 0.78 mm, (P < .05). In two of the 29 lesions, cryoenergy induced minor coronary artery injury with mild medial and adventitial thickening as well as minimal intimal proliferation, which had neither been detected by coronary angiography nor by ICUS.

CONCLUSION

Late after double cryoenergy application at growing myocardium, subclinical minor affection of the coronary artery wall could be detected with minimal intimal proliferation. As lifetime sequelae of this finding remains unknown, further studies are warranted to address safety of repeated cycles of cryoenergy application for tachycardia substrates in children.

Transseptal Puncture for Catheter Ablation in Children

Transseptal puncture (TP) is used in pediatric patients to access the left atrium in left-sided arrhythmia catheter ablation. Performing this procedure can be difficult and risky, especially in small children. In this study, we aimed to evaluate the safety and feasibility of TPs in children ≤ 30 kg. Between April 2012 and April 2018, a retrospective evaluation was conducted of the clinical features, procedural outcomes, and follow-ups of ≤ 30 kg pediatric patients who required TPs for left-sided ablations at a pediatric electrophysiology center in which a three-dimensional mapping system was routinely used. A total of 45 pediatric patients who were ≤ 30 kg, underwent TPs: 10 patients ≤ 20 kg (Group 1) and 35 patients > 20 kg and ≤ 30 kg (Group 2). The TP success rate was 97.8%. The median procedure and fluoroscopy times were 120 min and 5.43 min, respectively. One patient developed self-limited pericardial effusion during the procedure; however, there were no incidences of cardiac tamponade. There was no significant difference between the two groups in terms of the procedure time and fluoroscopy time, and pericardial effusion was only observed in Group 2. TPs are safe and feasible in small children. These procedures can be performed with low complication rates in children weighing ≤ 30 kg.

Catheter ablation for supraventricular tachycardia in children ≤ 20 kg using an electroanatomical system

PURPOSE

Catheter ablation is the only choice of treatment in some small children with medically refractory supraventricular tachycardia (SVT). Electroanatomical mapping systems (EMS) are more commonly utilized in electrophysiological procedures in recent years, which resulted in a significant decrease in fluoroscopy exposure. The potential benefit of EMS in small children has not been studied. Therefore, we investigated the outcomes of children undergoing catheter ablation weighing ≤ 20 kg using an electroanatomical mapping system.

METHODS

This study evaluated the outcomes, characteristics, and follow-ups of children ≤ 20 kg who underwent SVT ablations between April 2012 and April 2018 in a pediatric electrophysiology center where EMS were routinely used.

RESULTS

In a 6-year period, 1129 children underwent SVT catheter ablation under EMS guidance at our institution. A total of 84 of them were weighing ≤ 20 kg. The acute success rate was 97.6% in 85 tachycardia substrates. No fluoroscopy was used in 58 of the patients, while a median of 5 (4-14) min of fluoroscopy was used in the remaining 26 patients. Recurrences were seen in 4 patients (4.8%) at a mean follow-up of 3.89 ± 2.08 years. Five patients developed non-vital complications (2 right bundle block and 3 temporary complete block that spontaneously resolved during the procedure).

CONCLUSIONS

The outcome of catheter ablation with the guidance of EMS for the treatment of SVT in small children is favorable. Fluoroscopy exposure can be decreased and even eliminated in most patients.

Long-Term Follow-Up After Catheter Ablation of Atrioventricular Nodal Reentrant Tachycardia in Children

Background—

Catheter ablation of the slow conducting pathway (SP) is treatment of choice for atrioventricular nodal reentrant tachycardia (AVNRT). Although there are abundant data on AVNRT ablation in adult patients, little is known about the long-term results ≥3 years after AVNRT ablation in pediatric patients.

Methods and Results—

Follow-up data from 241 patients aged ≤18 years who had undergone successful AVNRT ablation were analyzed. Median age at ablation had been 12.5 years, and median follow-up was 5.9 years. Radiofrequency current had been used in 168 patients (70%), whereas cryoenergy had been used in 73 patients (30%). Procedural end point of AVNRT ablation had been either SP ablation (no residual dual atrioventricular nodal physiology) or SP modulation (residual SP conduction allowing for a maximum of one atrial echo beat). After the initial AVNRT ablation, calculated freedom from AVNRT was 96% at 1 year, 94% at 3 years, 93% at 5 years, and 89% at 8 years. Age, sex, body weight, the choice of ablation energy, and the procedural end point of AVNRT ablation did not impact freedom from AVNRT. Six of 22 AVNRT recurrences (27%) occurred ≥5 years after ablation. No late complications including atrioventricular block were noted.

Conclusions—

Cumulatively, catheter ablation of AVNRT continued to be effective in >90% of our pediatric patients during the long-term course. A significant part of recurrences occurred >5 years post ablation. Body weight, energy source, and the end point of ablation had no impact on long-term results. No adverse sequelae were noted.