Special considerations in mapping and ablation of focal ventricular arrhythmias originating from the left ventricular outflow tract in patients with a transcatheter aortic valve replacement

Transcatheter aortic valve replacements (TAVRs) have been increasingly performed in high‐risk patients with severe aortic stenosis. Focal ventricular arrhythmias (VAs) originating from the left ventricular outflow tract (LVOT) can occur after a TAVR, and radiofrequency catheter ablation (RFCA) should be considered as a treatment option when those VAs are drug‐refractory. There are specific challenges in the RFCA of LVOT VAs after a TAVR because the tubular structure of the TAVR device sits in the LVOT. However, if the anatomical background of the TAVR and LVOT VAs are well understood and the anatomical relationship between the TAVR device and LVOT is sufficiently evaluated, RFCA of LVOT VAs in patients with a TAVR should be safe and highly successful.     

Bipolar ablation of ventricular arrhythmias: Step-by-step

Radiofrequency (RF) ablation of intramural ventricular arrhythmias (VAs) may require advanced ablation techniques to achieve effective energy transfer to the targeted tissue. As an alternative to standard RF ablation, catheter ablation can also be conducted in bipolar configuration when two ablation catheters participate in the RF circuit. This strategy has proved to result in deeper lesion formation and may be effective for eliminating arrhythmias that have been refractory to standard ablation. In this article, we provide a step-by-step guide on when and how to perform bipolar ablation of VAs.     

导管消融治疗起源于主动脉根部附近室性期前收缩7例

目的：分析主动脉根部（AR）附近起源的室性期前收缩（室性早搏,室早）心电图特征和导管消融体会。方法：回顾性分析2010年6月～2012年8月在我院成功行导管射频消融治疗的AR附近起源的7例室早患者资料。结果：7例室早起源于主动脉窦上3例：右冠状动脉窦（RCC）起源1例,左冠状动脉窦（LCC）1例,LCC与RCC交界处1例;主动脉窦下4例：LCC下近RCC1例,主动脉瓣与二尖瓣连接处1例,LCC下左小叶三角1例,二尖瓣环12点1例。所有患者靶点腔内激动标测提示双极靶点电图领先体表心电图QRS波起点20～58（34±12）ms,4例（4／7）靶点部位可见室早时局部电位极性逆转。无消融相关并发症发生。结论：导管消融AR附近起源室早安全、有效,室早体表心电图可初步判断起源部位,标测和消融时注意局部电位特征。     

Electrophysiological study prior to planned pulmonary valve replacement in patients with repaired tetralogy of Fallot

Aim

Ventricular arrhythmias (VAs) are the most common cause of death in patients with repaired Tetralogy of Fallot (rTOF). However, risk stratifying remains challenging. We examined outcomes following programmed ventricular stimulation (PVS) with or without subsequent ablation in patients with rTOF planned for pulmonary valve replacement (PVR).

Methods

We included all consecutive patients with rTOF referred to our institution from 2010 to 2018 aged ≥18 years for PVR. Right ventricular (RV) voltage maps were acquired and PVS was performed from two different sites at baseline, and if non-inducible under isoproterenol. Catheter and/or surgical ablation was performed when patients were inducible or when slow conduction was present in anatomical isthmuses (AIs). Postablation PVS was undertaken to guide implantable cardioverter-defibrillator (ICD) implantation.

Results

Seventy-seven patients (36.2 ± 14.3 years old, 71% male) were included. Eighteen were inducible. In 28 patients (17 inducible, 11 non-inducible but with slow conduction) ablation was performed. Five had catheter ablation, surgical cryoablation in 9, both techniques in 14. ICDs were implanted in five patients. During a follow-up of 74 ± 40 months, no sudden cardiac death occurred. Three patients experienced sustained VAs, all were inducible during the initial EP study. Two of them had an ICD (low ejection fraction for one and important risk factor for arrhythmia for the second). No VAs were reported in the non-inducible group (p < .001).

Conclusion

Preoperative EPS can help identifying patients with rTOF at risk for VAs, providing an opportunity for targeted ablation and may improve decision-making regarding ICD implantation.     

Retrograde aortic access during ventricular tachycardia ablation: Indications,techniques, and challenges

The retrograde aortic (RA) route is a widely used access route for mapping and ablation of ventricular tachycardias (VT) arising from the left ventricular endocardium. With the expanding role of VT ablation in patients with significant comorbidity, the choice between the RA and transseptal access routes is an increasingly important consideration. An individualized decision based on the location of the arrhythmogenic substrate, vascular anatomy, aortic valve morphology, and operator experience is necessary when deciding on the optimal access route. Among patients with challenging vascular anatomy, growing experience from structural interventions such as transcatheter aortic valve replacements and peripheral vascular interventions has provided valuable insights into techniques for safe retrograde access. The present review focuses on patient selection for RA access, potential complications associated with the technique, and optimal approaches for access in patients with challenging vascular or aortic valve anatomy.     

Catheter ablation of peri-AV nodal atrial tachycardia from the noncoronary cusp of the aortic valve

Introduction: Atrial tachycardias (AT) originating from the anteroseptal region of the aortic root, near the atrioventricular node can be challenging to eliminate safely by catheter ablation. In this study, we examine the characteristics of anteroseptal ATs in a cohort of patients at our centers, and demonstrate the long-term efficacy and safety of targeting the arrhythmias from within the base of the noncoronary aortic valve cusp (NCC).
Methods & Results: From among a cohort of 54 patients with symptomatic focal AT undergoing invasive electrophysiological evaluation, the point of earliest right atrial (RA) activation was at the peri-AV nodal region in 10 patients, just postero-superior to the His-bundle. Before further mapping, RA lesions placed in two patients were unsuccessful in eliminating the arrhythmia. Because of its proximity to the interatrial septum, the base of the NCC was mapped using a retrograde aortic approach, and revealed a point of early activation without the presence of a His potential. The arrhythmia terminated with <10 seconds of radiofrequency or cryothermal energy delivery and was successfully eliminated in 7 of 10 patients. Transient termination or acceleration of the AT was noted in the other three patients, prompting successful ablation from a left atrial septal position or a reattempt from a para-Hisian RA position. All patients have been arrhythmia free during follow-up (41 ± 12 months).
Conclusions: Catheter ablation from within the base of the NCC represents a safe and effective means to eliminate focal AT arising from the peri-AV nodal region.     

Ablation catheter entrapment by chordae tendineae in the mitral valve during ventricular tachycardia ablation

We report on the entrapment of an ablation catheter by chordae tendineae in the mitral valve during radiofrequency (RF) ablation of ventricular tachycardia. The entrapped tip had to be removed via open surgery. Great care must be taken when performing radiofrequency ablation around the mitral valve apparatus.     

Papillary muscle ventricular ectopy ablation in a malignant mitral valve prolapse

Patients with mitral valve prolapse (MVP) have a heterogeneous clinical spectrum, ranging from benign to severe clinical presentations such as sudden cardiac death (SCD). Some of the markers of “arrhythmic MVP” include inverted/biphasic T-waves, QT prolongation, and polymorphic premature ventricular contractions (PVCs) originating from the left ventricular outflow tract and papillary muscles (PMs). The genesis of arrhythmias in MVP recognizes the combination of the substrate (fibrosis) and the trigger (mechanical stretch). Therefore, ablation of ventricular arrhythmias originating from PMs in a patient with MVP can be considered an adjunctive strategy to lower the arrhythmic burden and reduce the risk of ICD shocks.     

Electrocardiographic features of failed and recurrent right ventricular outflow tract catheter ablation of idiopathic ventricular arrhythmias

1 Introduction

Various ECG algorithms have been proposed to identify the origin of idiopathic outflow tract (OT)‐ventricular arrhythmia (VA). However, electrocardiographic features of failed and recurrent right ventricular outflow tract (RVOT) ablation of idiopathic OT‐VAs have not been clearly elucidated.

2 Methods and results

A total of 264 consecutive patients (mean age: 44.0 ± 13.0 years, 96 male) undergoing RVOT ablation for OT‐VAs with a transition ≥V₃, including 241 patients (91.6%) with initially successful procedures and 23 patients (8.4%) with failed ablation. Detailed clinical characteristics and ECG features were analyzed and compared between the two groups. VAs with failed RVOT ablation had larger peak deflection index (PDI), longer V₂ R wave duration (V₂Rd), smaller V₂ S wave amplitude, higher R/S ratio in V₂, higher V₃ R wave amplitude, and larger V₂ transition ratio than those with successful ablation. Multivariate analysis demonstrated that PDI, V₂Rd, V₂ transition ratio, and pacemapping score acquired during mapping independently predicted failed ablation (P  =  0.01, P  =  0.01, P  =  0.01, and P < 0.001, respectively). In 31 recurrent cases (12.8%) after initially successful ablation, multivariate Cox regression analysis showed that only the earliest activation time acquired during mapping predicted the recurrences after successful ablation (P  =  0.001). The recurrent cases displayed different ECG features comparing with those with failed ablation.

3 Conclusion

The electrocardiographic features of failed RVOT ablation of idiopathic OT‐VAs with a transition ≥V₃ were characterized by PDI, V₂Rd, V₂ transition ratio, and pacemapping score acquired during mapping, unlike the recurrent RVOT ablation.     

Clinical outcomes of radiofrequency catheter ablation of ventricular tachycardia in patients with hypertrophic cardiomyopathy

Background

Monomorphic ventricular tachycardia (VT) is rare in patients with hypertrophic cardiomyopathy (HCM), management of which is challenging. Limited data exists on the utility of catheter ablation for the treatment of VT in this population.

Objectives

We aimed to assess clinical outcomes of catheter ablation for VT in HCM patients.

Methods

A systematic search, without language restriction, using PubMed, EMBASE, SCOPUS, Google Scholar, and ClinicalTrials.gov was performed. The meta-analysis was performed using a meta-package for R version 4.0/RStudio version 1.2 and Freeman Tukey double arcsine method to establish the variance of raw proportions. Outcomes measured included (1) acute procedure success (defined as noninducible for clinical VT), (2) freedom from VT at follow-up, (3) mortality.

Results

This systematic review of six studies (three from the United States and three from Japan) incorporated a total of 68 drug-refractory HCM patients who underwent VT radiofrequency catheter ablation (mean age 57.6 ± 13.3 years, mean LVEF 45.8 ± 15.4%, 85% men, maximum septal wall thickness 17.4 ± 4.6 mm, and 32.3% with an apical aneurysm). Acute procedural success was achieved in 84.5% patients (95% confidence interval [CI]: 70.6%–95.2%) with 27.9% patients had recurrent VT requiring multiple ablations (median 1, IQR 1–3). During the follow-up period (18.3 ± 11.7 months), the pooled incidence of freedom from recurrent VT after index procedure was 70.2% (95% CI: 51.9%–86.2%), while after the last ablation was 82.8% (95% CI: 57%–99.2%). There were two deaths during follow-up, one from heart failure and one from SCD 0.8% (95% CI: 0%–5.8%).

Conclusion

The results of our pooled analysis demonstrated that catheter ablation for VT in HCM patients was associated with high acute procedural success, and reduced VT recurrence—findings comparable to previously published reports in other disease substrates.     

心室反应在射频消融特发性室性心动过速中作用的临床研究

目的　探讨心室反应 (VR)在射频消融IVT的作用。方法　应用体表心电图、心内膜激动标测及VR相结合的方法射频消融 13例IVT病人。以激动标测初选靶点 ,射频消融试放电产生的VR确定靶点 ,采用VR与VT发作相一致处为靶点消融。结果　 13例IVT即刻消融成功率 13/ 13。VR表现 :(1)窦性心律下消融时出现与VT发作相一致的VR。随后室性心动过速 (VT)中间断出现窦性心律、双发或联律室性早搏 ,最终完全恢复成窦性心律。 (2 )出现与VT发作不一致的VR。结论　以VR与VT发作相一致处作靶点 ,产生与VT发作相一致的VR可被视为有效消融的指标。