Different Approaches for Catheter Ablation of Para-Hisian Accessory Pathways

Comparison between cryotherapy and radiofrequency energy sources for parahisian accessory pathway percutaneous ablation

BACKGROUND

Catheter ablation of parahisian accessory pathways (PHAP) are challenging due to their proximity to the normal conduction system. Retrospective studies suggest that cryoablation has a better safety profile but a higher recurrence rate when compared to radiofrequency ablation (RFCA). The objective of this study was to compare the results of parahisian AP ablation performed by electrophysiologists with experience in both technologies.

METHODS

Prospective single-center, non-blinded and 1:1 model was used. Patients included had parahisian AP confirmed by an electrophysiological study and referred for radiofrequency or cryotherapy ablation according to current guidelines, under fluoroscopic guidance. No electroanatomic mapping was used.

RESULTS

A total of 30 patients (mean age of 25±9.4 years; 90% male) were enrolled between Oct/2018 to Feb/2020. Acute success rate between RFCA and CRYO were similar (93% vs. 87%, p = 0.54). A nonsignificant reduction in short-term recurrence rate for RFCA (14% vs. 30%, p = 0.3) and mechanical trauma (6% vs. 20%; p = 0.28) was observed. Long-term recurrence rate and event-free survival time were similar in both groups after 1-year follow-up (p = 0.286). No persistent complete AV block or conduction disturbance was also observed.

CONCLUSION

Considering the limitation of a small sample size and the lack of use of electroanatomic mapping for RFCA, the efficacy and safety profile of parahisian AP ablation with RFCA was not different from CRYO, when performed by experienced electrophysiologists. No cases of permanent complete AV block were reported with either energy modalities.

Trans-jugular approach for safe and successful cryoablation of para-Hisian/anterior-septal, anterior, and anterior-lateral accessory pathways in children

BACKGROUND

Cryoablation of APs localized near the atrioventricular (AV) junction is a well-established ablation strategy in children, and it has proved to be very safe. However, recurrence rates remain considerable for specific accessory pathway (AP) localizations. The aim of this retrospective study was to evaluate the efficacy and safety of a trans-jugular approach for cryoablation of right anterior, anterior-lateral, and anterior-septal APs in children, as compared to the conventional femoral approach.

METHODS

From June 2019 to November 2023, 24 consecutive patients (mean age 13.2 ± 4.6, 12 males (50% of total cohort)) with right anterior-lateral, anterior, and anterior-septal/para-Hisian APs underwent 3D non-fluoroscopic transcatheter cryoablation through the right jugular vein at our Institution. Ablation results were compared with 24 patients for whom a conventional trans-femoral approach was used.

RESULTS

Acute procedural success rate was 100% (n = 24/24), with a non-statistically significant difference as compared to the control group (100% vs. 83%, p = 0.1). During follow-up (1.1 years, interquartile range 0.6-1.3), one patient (4%) had a recurrence in the trans-jugular group, as opposed to eight (38%) in the control group (p = 0.006). No permanent complications occurred.

CONCLUSIONS

3D cryoablation of right anterior-lateral, anterior, and anterior-septal/para-Hisian APs in children using a trans-jugular approach is extremely effective and safe, resulting in higher chronic success rate compared to the conventional femoral approach.

Safety and efficacy of catheter ablation of para-Hisian accessory pathway via a direct superior vena cava approach: A multicenter study

BACKGROUND

Radiofrequency (RF) catheter ablation of para-Hisian accessory pathways (APs) can be challenging due to proximity to the conduction system.

METHODS

A total of 30 consecutive patients with para-Hisian AP were enrolled for ablation in three centers, 12 (40%) of whom had previously failed attempted ablation from the inferior vena cava (IVC) approach. Ablation was preferentially performed using a superior approach from the superior vena cava (SVC) in all patients.

RESULTS

The para-Hisian AP was eliminated from the SVC approach in 28 of 30 (93.3%) patients. In the remaining two patients, additional ablation from IVC was required to successfully eliminate the AP. There were two patients experienced reversible complete atrial-ventricular block and PR prolongation during the first RF application. Long-term freedom from recurrent arrhythmia was achieved in 29 (96.7%) patients over a mean follow-up duration of 15.6 ± 4.6 months.

CONCLUSION

Catheter ablation of para-Hisian AP from above using a direct SVC approach is both safe and effective, and should be considered especially in patients who have failed conventional ablation attempts from IVC approach.

A new insight into the different approaches for the ablation of para-Hisian accessory pathways: safety, effectiveness, and mechanism

BACKGROUND

To compare the safety, effectiveness, electrophysiological characteristics, and mechanisms of different approaches for the ablation of para-Hisian accessory pathways (APs).

METHOD

Eighteen consecutive patients with para-Hisian APs were enrolled in this study. Detailed mapping of retrograde conduction as well as antegrade conduction (if possible) in both the right sided His bundle region and non-coronary cusp (NCC) region was performed before ablation. Ten patients underwent initial ablation in the right septal (RS) region while the remaining 8 patients were ablated in NCC region. Repeat ablation was attempted in an alternative region if ablation at the first site failed.

RESULTS

Among the patients whose procedures were successful, 7 cases were successfully ablated with a NCC approach while 10 were conventionally ablated in RS region. For successful procedures targeting the NCC region, the earliest atrial activation (EAA) in NCC region preceded that at RS region by 4-13 ms. The distance between NCC targets and near-field His potential (NFH) points was longer than that between RS targets and NFH points. Additionally, the risk of complication after ablation in NCC region was lower compared with that following RS-targeted procedure.

CONCLUSION

NCC approach provided a high success rate and low risk of complication for the ablation of para-Hisian APs as long as EAA was observed in NCC region. Sites of successful para-Hisian AP ablation in NCC region had different retrograde mapping patterns in comparison with successful ablation sites in the RS region.

Two decades of experience on ablation in children with Ebstein's anomaly

INTRODUCTION

Accessory pathways are commonly seen due to delamination of tricuspid valve leaflets. In addition to accessory pathways, an enlarged right atrium due to tricuspid regurgitation and incisional scars creates substrates for atrial re-entries and ectopic tachycardia. We sought to describe our experience with catheter ablation in children with Ebstein's anomaly.

METHODS AND RESULTS

During the study period, of 89 patients diagnosed with Ebstein's anomaly, 26 (30.9%) of them who underwent 33 ablation procedures were included in the study. Accessory pathways were observed in the majority of procedures (n = 27), whereas atrial flutter was observed in five, atrioventricular nodal reentrant tachycardia in five, and atrial tachycardia in two procedures. Accessory pathways were commonly localised in the right posteroseptal (n = 10 patients), right posterolateral (n = 14 patients), septal (n = two patients), and left posteroseptal (n = one patient) areas. Multiple accessory pathways and coexistent arrhythmia were observed in six procedures. All ablation attempts related to the accessory pathways were successful, but recurrence was observed in five (19%) of the ablations. Ablation for atrial flutter was performed in five patients; two of them were ablated successfully. One of the atrial tachycardia cases was ablated successfully.

CONCLUSIONS

Ablation in patients with Ebstein's anomaly is challenging, and due to nature of the disease, it is not a rare occasion in this group of patients. Ablation of accessory pathways has high success, but also relatively high recurrence rates, whereas ablation of atrial arrhythmias has lower success rates, especially in operated patients.

Outcomes of Different Ablation Approaches for Para-Hisian Accessory Pathway and Ablation Safety at Each Site

Background

This study describes the electrophysiologic characteristics of the para-hisian accessory pathway (AP), the outcome of different ablation approaches, and ablation safety at different sites.

Method

A total of 120 patients diagnosed as para-hisian AP were included in this study. The electrophysiologic characteristics and outcomes at different ablation sites were analyzed.

Results

In total, 107 APs and 13 APs were diagnosed as right anteroseptal (RAS) and right midseptal (RMS), respectively. The significant ECG difference between RAS and RMS was lead III, which mainly manifested as positive and negative delta waves, respectively. Catheter trauma to AP was recorded in 21 of 120 (17.5%) patients. The recurrence rate of direct ablation at the “bumped” sites was higher than the conventional ablation method (37.5 vs. 14.1 %, p = 0.036). For RAS APs, there was no significant difference in the success rate between the inferior vena cava (IVC) and superior vena cava (SVC) approaches (76.6 vs. 73.3%, p = 0.63). The RAS was separated into three regions: (1) Site 1: superior part above the real “His” recorded site with far-field “His” potential; (2) Site 2 (true para-hisian): the site with near-field “His” potential; and (3) Site 3: inferior part below the biggest real “His” with far-field “His” potential. Mid-septal was defined as an area that is bounded anteriorly by His recording location and posteriorly by the roof of coronary sinus (CS) ostium. The incidence of atrioventricular (AV) conduction injury at different sites was as follows: 3 of 6 (50%) at Site 2, 4 of 13 (30.8%) at RMS, 7 of 34 (20.6%) at Site 3, and 3 of 46 (6.5%) at Site 1. Even if ablation was performed at the atrial side of the para-hisian region, the right bundle branch block (RBBB) was caused in 6 patients (5%).

Conclusion

Ablation via IVC or SVC was comparative for para-hisian APs, but not for the noncoronary cusp (NCC) approach. The AV conduction injury risk ranks as follows: Site 2 > RMS > Site 3 > Site 1. RBBB could be caused while ablating at the atrial side, which could further demonstrate the His bundle longitudinal dissociation theory.

Intracardiac Echocardiography to Guide the Ablation of Parahisian Arrhythmias

Arrhythmias from the perinodal region have been described for accessory pathways (APs), atrial tachycardias (AT), premature ventricular complexes (PVCs), and ventricular tachycardia (VT). The parahisian (PH) region encompasses anatomic structures that include the atrioventricular (AV) node and His-Bundle (HB). These locations are at high-risk for inducing AV block during catheter ablation in the electrophysiology laboratory. PH arrhythmias were initially defined as having sites of origin within 10 mm of the largest HB potential (>0.1 mV) recording site, but more recent definitions have included any site that has an HB potential at the ablation site. Intracardiac echocardiography (ICE) use offers real-time visualization of the catheter tip-to-tissue contact and can monitor for acute complications during atrial and ventricular procedures. ICE also enables a broad appreciation of real-time cardiac structures, which is invaluable in navigating the complex anatomy of the PH region.

Methodology of Typical Accessory Pathway Catheter Ablation

Accessory pathways are abnormal electrical conductions between the atrial and ventricular myocardium, bypassing the atrioventricular node and as such are an important substrate for arrhythmias. Ablation is a curative treatment and should always be offered to symptomatic patients and asymptomatic patients with high risk professions. Adequate knowledge and understanding of different mapping and ablation techniques is pivotal to achieve successful outcomes.

Uncovering a unique path: Antidromic AVRT utilizing a left anteroseptal Mahaim-like accessory pathway

A 40-year-old man presented to our emergency department 2 hours after onset of shortness of breath, palpitations, and presyncope secondary to an adenosine-responsive wide complex tachycardia. Electrophysiology study was diagnostic for antidromic atrioventricular (AV) reentrant tachycardia utilizing a muscular connection from the anterior interventricular vein to the left ventricle with Mahaim-like properties, successfully treated with ablation in the distal coronary sinus (CS) system. This case highlights accessory pathways (a) with unique features (i.e., Mahaim-like characteristics) and (b) involving musculature from the distal CS system, thereby limiting the value of endocardial ablation for durable treatment. Importantly, the coronary venous system is an accessible vascular network for evaluation and catheter ablation of such arrhythmias.

Single-shot cryoablation of an epicardial inferoparaseptal accessory pathway: a case report

Background

Catheter ablation (CA) of epicardial accessory pathways (APs) can be performed via the coronary sinus (CS) system. Variable CS anatomy with complications of former CA procedures inside the CS venous system may require using alternative CA approach and technology.

Case summary

We report the case of a 23-year-old man with Wolff-Parkinson-White syndrome and history of aborted sudden cardiac death (SCD) and unsuccessful previous AP radiofrequency ablation (RFA). CS venography during the redo procedure revealed an early CS trifurcation with cardiac veins stenosis, thus with difficulties in maintaining cardiac veins' access and catheter manoeuvring inside CS venous system. The last office visit with electrocardiogram (ECG) performance was in 3 months after the CA. Neither delta wave on the ECG nor any complaints/adverse health effects was detected at that time.

Discussion

Successful CA of epicardial AP in patients with a high risk of SCD is essential. However, CS complex anatomy and changes after former RFA inside it may lead to CS venous system access limitations. Alternative CA approach and technology should be considered to ensure CS venous system cannulation and epicardial AP CA performance.