Updated results on catheter ablation of ventricular arrhythmias arising from the papillary muscles of the left ventricle

Transseptal approach versus retrograde aortic approach in mapping and ablation of ventricular arrhythmias from anterolateral papillary muscles

INTRODUCTION

The anterior and lateral position of the anterolateral papillary muscle (ALPM) has found to be reached with better catheter stability and less mechanical bumping via the transseptal (TS) compared to the retrograde aortic (RA) approach. The aim of this study is to compare the TS and RA approaches on mapping and ablation of ventricular arrhythmias (VAs) arising from ALPMs.

METHODS

Thirty-two patients with ALPM-VAs undergoing mapping and ablation via the TS approach were included and compared with 31 patients via the RA approach within the same period. Acute success was compared, as well as other outcomes including misinterpreted mapping results due to bumping, radiofrequency (RF) attempts, procedural time and success rate at 12-month follow-up.

RESULTS

Acute success was achieved in more cases in the TS group (96.4% vs. 72.0%, p = .020). During activation mapping, bump-provoked premature ventricular complexes (PVCs) misinterpreted as clinical PVCs were more common in the RA group (30.0% vs. 58.3%, p = .036), leading to more RF attempts (3.5 ± 2.7 vs. 7.2 ± 6.8, p = .006). Suppression of VAs were finally achieved in the unsuccessful cases by changing to the alternative approach, but the procedural time was significantly less in the TS group (90.0 ± 33.0 vs. 113.7 ± 41.1 min, p = .027) with less need to change the approach, although follow-up success rates were similar (75.0% vs. 71.0%, p = .718).

CONCLUSION

A TS rather than RA approach as the initial approach appears to facilitate mapping and ablation of ALPM-VAs, specifically by decreasing the possibility of misleading mapping results caused by bump-provoked PVC, and increase the acute success rate thereby.

Arrhythmic Mitral Valve Prolapse Syndrome and Ventricular Arrhythmias: A Comprehensive Review and the Role of Catheter Ablation

Mitral valve prolapse (MVP) affects 2-3% of the general population, and despite its benign prognosis overall, it is associated with sudden death in a small subset of patients. The term "arrhythmic MVP syndrome" (AMVPS) refers to the presence of frequent or complex ventricular arrhythmias, commonly reported in female patients with a stereotypical phenotype including bileaflet myxomatous disease, ECG repolarisation abnormalities in inferior leads, mitral annular disjunction, and significant fibrosis in the inferolateral LV and papillary muscles. Modern imaging technologies have led to the identification of new risk factors that have been implemented in recent risk stratification guidelines; however, screening for patients with MVP who are at risk of sudden cardiac death (SCD) remains challenging. In addition, there is a limited amount of data on the outcomes of different treatment approaches in AMVP and no specific indication for targeted or disease-modifying therapies within current guidelines. Potential arrhythmic substrates in patients with AMVP syndrome have been the subject of interest in previous studies, with areas consisting of fibrosis at the papillary muscle level and the Purkinje system. Premature ventricular contractions (PVCs) originating from these areas have been shown to play an important role as triggers for ventricular fibrillation and SCD in patients with AMVP. Catheter ablation has emerged as a potential treatment modality in patients with MVP and ventricular arrhythmias (VAs), targeting arrhythmic substrates and triggering PVC foci. The aim of this review is to explore the role of catheter ablation in treating patients with AMVP.

Arrhythmic Mitral Valve Prolapse and Sports Activity: Pathophysiology, Risk Stratification, and Sports Eligibility Assessment

Although mitral valve prolapse (MVP) is the most prevalent valvular abnormality in Western countries and generally carries a good prognosis, a small subset of patients is exposed to a significant risk of malignant ventricular arrhythmias (VAs) and sudden cardiac death (SCD), the so-called arrhythmic MVP (AMVP) syndrome. Recent work has emphasized phenotypical risk features of severe AMVP and clarified its pathophysiology. However, the appropriate assessment and risk stratification of patients with suspected AMVP remains a clinical conundrum, with the possibility of both overestimating and underestimating the risk of malignant VAs, with the inappropriate use of advanced imaging and invasive electrophysiology study on one hand, and the catastrophic occurrence of SCD on the other. Furthermore, the sports eligibility assessment of athletes with AMVP remains ill defined, especially in the grey zone of intermediate arrhythmic risk. The definition, epidemiology, pathophysiology, risk stratification, and treatment of AMVP are covered in the present review. Considering recent guidelines and expert consensus statements, we propose a comprehensive pathway to facilitate appropriate counseling concerning the practice of competitive/leisure-time sports, envisioning shared decision making and the multidisciplinary "sports heart team" evaluation of borderline cases. Our final aim is to encourage an active lifestyle without compromising patients' safety.

Is catheter-tissue contact force value important for ablation of ventricular arrhythmias originating from the left ventricular papillary muscles?

Background

Good catheter-tissue contact is mandatory to create effective ablation lesions. The minimal contact force value for ablation of arrhythmias originating from the left ventricle is 8.0-10.0 grams but is not known for arrhythmias arising from papillary muscles.

Purpose

To analyze contact force values during successful ablation procedures of arrhythmias originating from the left ventricular papillary muscles.

Methods

24 consecutive patients (mean age 57.9 ± 11.9 years, 16 males) underwent ablation of premature ventricular complexes originating from left ventricular papillary muscles with the use of CARTO electro-anatomical system and intracardiac echocardiography.

Results

Acute complete abolition of ventricular ectopy was obtained in 23 (96%) patients. The fluoroscopy time was 3.9 ± 3.5 min and procedure duration - 114.8 ± 37.9 min. The mean contact force during successful ablations was 3.0 ± 1.1 grams and 3.18 ± 1.8 grams for antero-lateral and postero-medial papillary muscle, respectively (NS). The mean contact force during a single unsuccessful ablation was 3.0 grams. At control Holter ECG, the mean Ectopy Burden was Reduced in the Antero-Lateral Papillary Muscle Group from 18.0% ± 7.9% to 2.6% ± 2.9% (p = 0.005415) and in the Postero-Medial Papillary Muscle Group - from 34.8% ± 13.7%-1.7% ± 1.3% (p = 0.012694). During Median 27 (IQR: 17-34) Months of Follow-up There one Recurrence of Arrhythmia.

Conclusion

The values of contact force for successful ablation of ventricular ectopy originating from the left ventricular papillary muscles may be much lower than those for ablation of other foci which questions the role of contact force measurement when ablating these arrhythmias.

Combination of Intracardiac Echocardiography and Contact Force Sensing for Left Ventricular Papillary Muscle Arrhythmias

OBJECTIVES

The catheter ablation of ventricular arrhythmias (VAs) arising from the left ventricular (LV) papillary muscles (PMs) is challenging. This study sought to address whether the combination of intracardiac echocardiography (ICE) and contact force sensing (CFS) can improve the acute and long-term ablation outcomes of left ventricular papillary muscle arrhythmias.

METHODS AND RESULTS

From May 2015 to August 2022, a total of thirty-three patients underwent catheter ablation for LV PM arrhythmias: VAs were located in anterolateral PMs in 11 and posteromedial PMs in 22. A combination of intracardiac echocardiography (ICE) and contact force sensing (CFS) was used in 21 of the 33 procedures. A mean of 6.93 ± 4.91 for lesions was used per patient, comparable between the CFS/ICE and no ICE/CFS (4.90 ± 2.23 vs. 10.17 ± 5.89; p = 0.011). The mean CF achieved in the ICE/CFS group was 7.52 ± 3.31 g. Less X-ray time was used in the combination group (CFS/ICE: 165.67 ± 47.80 S vs. no ICE/CFS: 365.00 ± 183.73 S; p < 0.001). An acute success rate of 100% was achieved for the ICE/CFS group (n = 22) and 66.67% for the no ICE/CFS group (n = 8). VA recurrence at the 11.21 ± 7.21-month follow-up was 14.2% for the ICE/CFS group and 50% for the no ICE/CFS group (p = 0.04). No severe complications occurred in all patients.

CONCLUSIONS

The combination of intracardiac echocardiography (ICE) and contact force sensing (CFS) could provide precise geometries of cardiac endocavitary structures and accurate contact information for the catheter during ablation, which improved acute and long-term ablation outcomes. The routine adoption of this strategy should be considered to improve the outcomes of LV PM VA ablation.

Understanding the scope of intracardiac echocardiography in catheter ablation of ventricular arrhythmia

Over the last few decades, catheter ablation has emerged as the first-line treatment for ventricular arrhythmias. However, detailed knowledge of cardiac anatomy during the surgery remains the prerequisite for successful ablation. Intracardiac echocardiography (ICE) is a unique imaging technique, which provides real-time visualization of cardiac structures, and is superior to other imaging modalities in terms of precise display of cardiac tissue characteristics as well as the orientation of anatomical landmarks. This article aimed to introduce the various advantages and limitations of ICE in the ablation of ventricular arrhythmias.

ORIGINAL ARTICLESCatheter Ablation For Papillary Muscle Arrhythmias A Systematic Review

Background

Catheter ablation of papillary muscle ventricular arrhythmias (PM‐VAs) has been associated with unsatisfactory results. Features that may affect acute and long‐term procedural outcomes are not well established.

Objective

To systematically review the available data in the literature assessing efficacy and safety of PM‐VAs catheter ablation.

Methods

An online search of PubMed, Cochrane Registry, Web of Science, Scopus and EMBASE libraries (from inception to March 1, 2021) was performed, in addition to manual screening. Twenty‐one observational noncontrolled case‐series were considered eligible for the systematic review, including 536 patients.

Results

Postero‐medial PM harbored 60.8% of PM‐VAs, while antero‐lateral PM and right ventricular PMs 34.9% and 4.3% of cases, respectively. The mean acute success rate of the index ablation procedure was 88.1% (95% CI 82.8% to 91.9%, p < .001, I² 0%). After a mean follow‐up period of 15.5 ± 17.4 months, pooled long‐term arrhythmia‐free rate was 69.2%, while the pooled long‐term success rate after multiple ablation procedure was 84.9%. Overall, procedure complications occurred in nine patients (1.7%) and no procedure‐related deaths were reported. The use of intracardiac echocardiography (ICE) as well as contact force sensing (CFS) and irrigated catheters during ablation was associated with higher rates of arrhythmia‐freedom at long‐term follow‐up.

Conclusions

Catheter ablation is an effective and safe strategy for PM‐VAs, with an acute success rate of 88.1%, a long‐term success rate of 69.2%, with a relatively low procedural complication rate. The use of ICE, irrigated catheters and catheters with CFS capability was associated with higher rates of arrhythmia‐freedom at long‐term follow‐up.

Cryoablation to improve catheter stability and ablation success in the right atrioventricular groove

Catheter instability can limit ablation success of arrhythmia substrates at the right atrioventricular groove. We describe cases where cryoablation improved catheter stability, enabling ablation success.

Methods and results

Four patients with supraventricular tachycardia (SVT) substrates at the right atrioventricular groove had radiofrequency ablation procedures limited by poor catheter contact. Cryoablation offered improved catheter stability, and all four patients achieved acute ablation success using cryoablation. Three patients had long-term success and one patient later required repeat radiofrequency ablation.

Conclusions

For patients with arrhythmia substrates at the right atrioventricular groove, cryoablation may be a useful adjunctive technique in cases with catheter instability.

Electrophysiological Substrate in Patients with Barlow's Disease

Mitral valve prolapse (MVP) is the most common valvular heart disease, affecting 2-3% of the general population. Barlow's disease is a clinical syndrome characterised by MVP. Initially thought a benign condition, MVP is now recognised as a cause of sudden cardiac death and ventricular arrhythmias. The development of new imaging techniques has contributed recently to the identification of novel risk factors. Catheter ablation of ventricular arrhythmias in patients affected by MVP is traditionally considered challenging. In this review, the authors summarise the evidence on arrhythmogenesis in the context of MVP, along with risk stratification of sudden cardiac death and the available treatment options, including new catheter ablation techniques.

Electrophysiological Substrates in Papillary Muscle Arrhythmias – Implications for Catheter Ablation

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