Risk Factors for Early Recurrence Following Ablation for Accessory Pathways: The Role of Consolidation Lesions

Outcomes of Focal Pulsed Field Ablation for Paroxysmal Supraventricular Tachycardia

BACKGROUND

Pulsed field ablation (PFA) is primarily used for treatment of atrial fibrillation as it provides better safety and efficacy. However, there are limited data available on the use of PFA for paroxysmal supraventricular tachycardia (PSVT). The study sought to describe the outcomes of PSVT ablation with a novel focal contact force (CF)-sensing PFA.

METHODS

In this first-in-human pilot study, a focal CF-sensing PFA catheter was used for mapping and ablation navigated with an electroanatomic mapping system (EAMS). Pulsed field energy was delivered as biphasic/bipolar electrical pulse trains with 2000 V/delivery. CF was controlled from 2 g to 10 g during PFA.

RESULTS

Procedural acute success was achieved without general anaesthesia or conscious sedation in all 10 patients, including 7 patients diagnosed with typical atrioventricular nodal re-entrant tachycardias and 3 patients with orthodromic reciprocating tachycardias. Successful target ablation time was 2.0 ± 0.5 seconds per patient, and the acute procedural success at the first single site was achieved in 5 patients. The mean skin-to-skin procedure time was 79.4 ± 15 minutes, PFA catheter dwell time was 50.1 ± 14 minutes, and fluoroscopy time was 6.2 ± 7 minutes. Maintenance of sinus rhythm was observed in all patients within 6-month follow-up. No serious adverse events occurred in any subjects during PFA or during the 6-month follow-up.

CONCLUSIONS

A focal CF-sensing PFA catheter could effectively, rapidly, and safely ablate PSVT in conscious patients.

CLINICAL TRIAL REGISTRATION

NCT05770921.

[Long-term results of catheter ablation for AV nodal reentry tachycardias and accessory pathways]

Atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia in patients with accessory pathways (AP) are common supraventricular tachycardias. High long-term efficacy of about 97% (AVNRT) and 92% (AP) has been observed in children and adults. The risk of occurring atrioventricular block is low (0.4-0.8% during AVNRT, 0.1-0.2% for AP). Catheter ablation shows a lower efficacy of 87-93% and elevated atrioventricular block risk up to 10% in patient groups with complex congenital heart disease. Nonsynchronized ventricular activation during preexcitation or permanent reentrant tachycardias can induce heart failure, and remission of left ventricular function can be expected in > 90% after successful catheter ablation. Therefore, catheter ablation is the long-term therapy of choice for AVNRT and AP with high efficacy and safety for most patient populations.

Retroflexed catheter course reduces the risk of right free wall accessory pathway recurrence

INTRODUCTION

Accessory atrioventricular pathways (APs) may mediate atrioventricular reciprocating tachycardia and, in some cases, have the potential to conduct atrial tachycardia rapidly, which can be life threatening. While catheter ablation can be curative, ablation of right free wall APs is associated with a high rate of recurrence, likely secondary to reduced catheter stability along the right free wall atrioventricular groove. We sought to identify characteristics associated with a lower rate of recurrence and hypothesized ablation lesions placed on the ventricular side of the atrioventricular groove using a retroflexed catheter approach would decrease rates of recurrence.

METHODS AND RESULTS

Retrospective chart review of patients who underwent catheter ablation of a right free wall AP from January 1, 2008 through June 1, 2021 with >2 months follow up. Cox proportional hazards regression was used to identify relationships between predictor variables and AP recurrence. We identified 95 patients who underwent ablation of 98 right free wall APs. Median age was 13.1 years and median weight at ablation was 52.3 kg. Overall, 23/98 (23%) APs recurred. Use of a retroflexed catheter course approaching the atrioventricular groove from the ventricular aspect was associated with reduced risk of AP recurrence with (univariable hazard ratio of 0.10 [95% confidence interval: 0.01-0.78]), which remained significant in multiple two variable Cox proportional hazards models.

CONCLUSION

Use of a retroflexed catheter course is associated with a reduced likelihood of AP recurrence. This approach results in improved catheter stability and should be considered for ablation of right free wall APs.

AMEN and ALARA - Remembering the dangers of the (new) technology of lesion formation

Catheter ablation in children has evolved to become a highly effective and safe therapy. Each iterative improvement in ablation technology provides another opportunity to investigate how much incremental benefit can be made without sacrificing safety. Contact force sensing catheters represent an example of such technology that has become commonplace in adult ablation. Its capability in predicting lesion size and collateral damage to critical structures has not been meticulously explored. Backhoff and colleagues describe an animal ablation model where they quantitate lesion characteristics at the atrium, atrioventricular groove, and ventricle using low and high contact force targets, with a specific focus on assessing for coronary arterial injury. In this controlled experiment, chronic lesion characteristics were widely variable (~0-8 mm diameter) yet there was a statistically significant (albeit small) increase in lesion diameter for high (vs low) contact force lesions delivered to the atrioventricular groove. The risk of chronic sub-clinical coronary artery injury was 1-2%. The remarkably weak association between contact force and lesion size suggests that delivery of clinical lesions needs to have both principles of As much as effectively needed (AMEN) and as low as reasonably achievable (ALARA), mirroring radiation exposure This article is protected by copyright. All rights reserved.

The feasibility of using remote magnetic navigation system as the primary technological training tool for novice cardiac electrophysiology operators in the catheter ablation of left-sided accessory pathway

BACKGROUND

For novice operators, mastering catheter ablation of left-sided accessory pathway (LSAP) in a short duration of time without compromising efficacy and safety remains a challenge. In this study an attempt to shorten the learning curve by using robotics via a remote magnetic navigation (RMN) system was performed.

METHODS

Novice physician fellows without prior catheter ablation experience initiated their process of learning LSAP ablation using the Niobe™ RMN system. Their procedure parameters were recorded and compared with experienced operators using RMN and manual catheter navigation (MCN).

RESULTS

Novice operators quickly shortened the total procedure time after their first five procedures. In subsequent procedures, no significant difference in procedure time, fluoroscopy exposure or ablation time was observed between novice and experienced RMN operators. When compared to MCN operators, novice operators avoided excessive radiation exposure beginning with their first RMN procedure, while lower fluoroscopy doses were noted after five procedures. It was observed that procedure parameters did not differ significantly according to LSAP location.

CONCLUSION

The RMN system is a practical and easy to use tool for novice electrophysiology operators to quickly master LSAP ablation, without compromising efficacy or safety. Additionally, when compared to MCN it also protects the operators and patients from excessive radiation exposure during the procedure.

Preprocedural Discrimination of Posteroseptal Accessory Pathways Ablated from the Right Endocardium from Those Requiring a Left-sided or Epicardial Coronary Venous Approach

The success of radiofrequency catheter ablation of the accessory pathway (AP) depends on the accurate localisation of the bypass tract. In that respect, posteroseptal or inferior paraseptal APs often pose a diagnostic challenge because of the complex anatomy at the crux of the four cardiac chambers. Considering the differences in procedure risks and success rate depending on the need for a left-sided approach or a coronary sinus ablation, an accurate anticipation of the precise location of inferior paraseptal APs is critical to inform the consent process and guide the initial mapping strategy. Here, the preprocedural clues to discriminate APs that can be ablated from the right atrium, from those requiring a left-sided or epicardial coronary venous approach, are reviewed. Both manifest and concealed APs will be considered and, following the diagnostic process made by the operator before interpretation of the intra-cardiac signals, each of the following aspects will be addressed: clinical context and initial probability; and 12-lead ECG analysis during baseline ECG with manifest AP, maximal preexcitation, and orthodromic reciprocating tachycardia.