Percutaneous cryoablation for papillary muscle ventricular arrhythmias after failed radiofrequency catheter ablation

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.

Mapping and Ablation of Premature Ventricular Complexes: State of the Art

Premature ventricular complexes (PVCs) are common arrhythmias in clinical practice. Although benign and asymptomatic in most cases, PVCs may result in disabling symptoms, left ventricular systolic dysfunction, or PVC-induced ventricular fibrillation. Catheter ablation has emerged as a first-line therapy in such cases, with high rates of efficacy and low risk of complications. Significant progress in mapping and ablation technology has been made in the past 2 decades, along with the development of a growing body of knowledge and accumulated experience regarding PVC sites of origin, anatomical relationships, electrocardiographic characterization, and mapping/ablation strategies. This paper provides an overview of the main indications for catheter ablation of PVCs, electrocardiographic features, PVC mapping techniques, and contemporary ablation approaches. The authors also review the most common sites of PVC origin and the main considerations and challenges with ablation in each location.

Twenty-five years of catheter ablation of ventricular tachycardia: a look back and a look forward

This article will discuss the past, present, and future of ventricular tachycardia ablation and the continuing contribution of the Europace journal as the platform for publication of milestone research papers in this field of ventricular tachycardia ablation.

Arrhythmic mitral valve prolapse in 2023: Evidence-based update

Patients with mitral valve prolapse (MVP) may develop ventricular arrhythmias, ranging from premature ventricular contractions through more complex non-sustained ventricular tachycardia to sustained life-threatening ventricular arrhythmias. The prevalence of MVP in autopsy series of young adults who died suddenly has been estimated to be between 4% and 7%. Thus, "arrhythmic MVP" has been reported as an underappreciated cause of sudden cardiac death, leading to a renewed interest in the study of this association. The term "arrhythmic MVP" refers to a small subset of patients who have, in the absence of any other arrhythmic substrate, MVP, with or without mitral annular disjunction, and frequent or complex ventricular arrhythmias. Our understanding of their coexistence in terms of contemporary management and prognosis is still incomplete. While literature regarding the arrhythmic MVP may be contrasting despite recent consensus document, the present review summarizes the relevant evidence concerning the diagnostic approach, prognostic implications, and targeted therapies for MVP-related ventricular arrhythmias. We also summarize recent data supporting left ventricular remodeling, which complicates the coexistence of MVP with ventricular arrhythmias. As the evidence for a putative link between MVP-associated ventricular arrhythmias and sudden cardiac death is scarce and based on scant and retrospective data, risk prediction remains a challenge. Thus, we aimed at listing potential risk factors from available seminal reports for further use in a more reliable prediction model that requires additional prospective data. Finally, we summarize evidence and guidelines on targeted therapies of ventricular arrhythmias in the setting of MVP, including implantable cardioverter defibrillators and catheter ablation. Our review highlights current knowledge gaps and provides an action plan for structured research on the pathophysiological genesis, diagnosis, prognostic impact, and optimal management of patients with arrhythmic MVP.

Best Practices for the Catheter Ablation of Ventricular Arrhythmias

Techniques for catheter ablation have evolved to effectively treat a range of ventricular arrhythmias. Pre-operative electrocardiographic and cardiac imaging data are very useful in understanding the arrhythmogenic substrate and can guide mapping and ablation. In this review, we focus on best practices for catheter ablation, with emphasis on tailoring ablation strategies, based on the presence or absence of structural heart disease, underlying clinical status, and hemodynamic stability of the ventricular arrhythmia. We discuss steps to make ablation safe and prevent complications, and techniques to improve the efficacy of ablation, including optimal use of electroanatomical mapping algorithms, energy delivery, intracardiac echocardiography, and selective use of mechanical circulatory support.

Impact of Left Ventricular Papillary Muscle Ventricular Arrhythmia Ablation on Mitral Valve Function

BACKGROUND

Although efficacious, catheter ablation (CA) of ventricular arrhythmias (VAs) originating from left ventricular (LV) papillary muscles (PAPs) has the potential to affect mitral valve (MV) function.

OBJECTIVES

The aim of this study was to determine whether lesions delivered during CA of VAs from LV PAPs affected MV function.

METHODS

Consecutive patients undergoing CA of LV PAP VAs from January 2015 to December 2020 in whom both preprocedural and postprocedural transthoracic echocardiography was performed were included. Radiofrequency ablation was performed with an irrigated-tip catheter with or without contact force sensing and intracardiac echocardiographic guidance. The PAPs were delineated into segments: tip, body, and base. Pre- and post-CA transthoracic echocardiograms were reviewed to assess MV regurgitation, which was graded 0 (none), 1 (mild), 2 (moderate), or 3 (severe). A change of ≥2 grades from baseline was considered significant.

RESULTS

A total of 103 patients (mean age 63 ± 15 years, 78% men) were included. VAs were ablated from the anterolateral PAP in 35% (n = 36), posteromedial PAP in 55% (n = 57), and both PAPs in 10% (n = 10). Lesion distribution was as follows: PAP tip in 52 (50%), PAP base in 34 (33%), PAP body in 13 (13%), and entire PAP in 4 (4%). The mean number of lesions delivered was 16 ± 13 (median 14). Of 103 patients, 102 (99%) showed no change in MV function.

CONCLUSIONS

Using intracardiac echocardiographic guidance, lesions can be safely delivered on various aspects of this structure without adverse impact on MV function.

Needle-Tipped Catheter Ablation of Papillary Muscle Results in Deeper and Larger Ablation Lesions

Ventricular tachycardia associated with papillary muscle (PM) is often refractory to standard radiofrequency ablation (RFA). The needle-tipped ablation catheter (NT-AC) has been used to treat deep intramyocardial substrates, but its use for PM has not been characterized. Using an ex vivo experimental platform, both 3 mm and 6 mm NT-AC created larger ablation lesion volumes and depths than open-irrigated ablation catheter did (OI-AC; e.g., 57.12 ± 9.70mm³ and 2.42 ± 0.22 mm, respectively; p < 0.01 for all comparisons). Longer NT-AC extension (6 mm) resulted in greater ablation lesion volumes and maximum depths (e.g., 333.14 ± 29.13mm³ and 6.46 ± 0.29 mm, respectively, compared to the shorter 3 mm NT-AC extension, 143.33 ± 12.77mm³, and 4.46 ± 0.14 mm; both p < 0.001). There were no steam pops. In conclusion, for PM ablation, the NT-AC was able to achieve ablation lesions that were larger and deeper than with conventional OI-AC. Ablation of PM may be another application for needle-tip ablation. Further studies are warranted to establish long-term safety and efficacy in human studies.

Cryoablation of Papillary Muscles at Surgery for Malignant Ventricular Arrhythmias Due to Mitral Valve Prolapse

BACKGROUND

Mitral Valve Prolapse (MVP) is relatively common condition and while generally benign a small subset of patient suffers from malignant ventricular arrhythmias (MVA) and sudden cardiac death (SCD).

METHOD AND MATERIAL

We report three cases of mitral valve prolapse, mitral regurgitation and malignant ventricular arrhythmias refractory to medical therapy, who had surgical cryoablation at the time of surgery on the mitral valve.

RESULTS

During a follow up period ranging from three to eleven years all three patients have remained free of ventricular arrhythmias and cryoablation lesions targeting the base of the papillary muscles have not caused any detrimental effect on the valve function.

CONCLUSION

Surgical cryoablation of papillary muscles as described in this article should be considered in MVP who suffer from MVA, aborted SCD or frequent ventricular ectopics likely to cause LV dysfunction.

Arrhythmic Mitral Valve Prolapse and Mitral Annular Disjunction: Clinical Features, Pathophysiology, Risk Stratification, and Management

Mitral valve prolapse (MVP) is a common cause of valvular heart disease. Although many patients with MVP have a benign course, there is increasing recognition of an arrhythmic phenotype associated with ventricular arrhythmias and sudden cardiac death (SCD). Pathophysiologic mechanisms associated with arrhythmias include cardiac fibrosis, mechanical stress induced changes in ventricular refractory periods, as well as electrophysiologic changes in Purkinje fibers. Clinically, a variety of risk factors including demographic, electrocardiographic, and imaging characteristics help to identify patients with MVP at the highest at risk of SCD and arrhythmias. Once identified, recent advances in treatment including device therapy, catheter ablation, and surgical interventions show promising outcomes. In this review, we will summarize the incidence of ventricular arrhythmias and SCD in patients with MVP, the association with mitral annular disjunction, mechanisms of arrhythmogenesis, methods for arrhythmic and SCD risk stratification including findings with multimodality imaging, and treatments for the primary and secondary prevention of SCD.

Arrhythmias in Patients With Valvular Heart Disease: Gaps in Knowledge and the Way Forward

The prevalence of both organic valvular heart disease (VHD) and cardiac arrhythmias is high in the general population, and their coexistence is common. Both VHD and arrhythmias in the elderly lead to an elevated risk of hospitalization and use of health services. However, the relationships of the two conditions is not fully understood and our understanding of their coexistence in terms of contemporary management and prognosis is still limited. VHD-induced left ventricular dysfunction/hypertrophy and left atrial dilation lead to both atrial and ventricular arrhythmias. On the other hand, arrhythmias can be considered as an independent condition resulting from a coexisting ischemic or non-ischemic substrate or idiopathic ectopy. Both atrial and ventricular VHD-induced arrhythmias may contribute to clinical worsening and be a turning point in the natural history of VHD. Symptoms developed in patients with VHD are not specific and may be attributable to hemodynamical consequences of valve disease but also to other cardiac conditions including arrhythmias which are notably prevalent in this population. The issue how to distinguish symptoms related to VHD from those related to atrial fibrillation (AF) during decision making process remains challenging. Moreover, AF is a traditional limit of echocardiography and an important source of errors in assessment of the severity of VHD. Despite recent progress in understanding the pathophysiology and prognosis of postoperative AF, many questions remain regarding its prevention and management. Furthermore, life-threatening ventricular arrhythmias can predispose patients with VHD to sudden cardiac death. Evidence for a putative link between arrhythmias and outcome in VHD is growing but available data on targeted therapies for VHD-related arrhythmias, including monitoring and catheter ablation, is scarce. Despite growing evidences, more research focused on the prognosis and optimal management of VHD-related arrhythmias is still required. We aimed to review the current evidence and identify gaps in knowledge about the prevalence, prognostic considerations, and treatment of atrial and ventricular arrhythmias in common subtypes of organic VHD.

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.

Newer Methods for VT Ablation and When to Use Them

Radiofrequency (RF) catheter ablation has long been an important therapy for ventricular tachycardia and frequent symptomatic premature ventricular beats and nonsustained arrhythmias when antiarrhythmic drugs fail to suppress the arrhythmias. It is increasingly used in preference to antiarrhythmic drugs, sparing the patient drug adverse effects. Ablation success varies with the underlying heart disease and type of arrhythmia, being very effective for patients without structural heart disease, less in structural heart disease. Failure occurs when a target for ablation cannot be identified, or ablation lesions fail to reach and abolish the arrhythmia substrate that may be extensive, intramural or subepicardial in location. Approaches to improving ablation lesion creation are modifications to RF ablation and emerging investigational techniques. Easily implemented modifications to RF methods include manipulating the size and location of the cutaneous dispersive electrode, increasing RF delivery duration, and use of lower tonicity catheter irrigation (usually 0.45% saline). When catheters can be placed on either side of culprit substrate RF can be delivered in a bipolar or simultaneous unipolar configuration that can be successful. Catheters with extendable/retractable irrigated needles for RF delivery are under investigation in clinical trials. Cryoablation is potentially useful in specific situations when maintaining contact is difficult. Transvascular ethanol ablation and stereotactic radioablation have both shown promise for arrhythmias that fail other ablation strategies. Although substantial clinical progress has been achieved, further improvement is clearly needed. With ability to increase ablation lesion size, continued careful evaluation of safety, which has been excellent for standard RF ablation, remains important.

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.

Utility of Intracardiac Echocardiography to Guide Transseptal Catheterization for Different Electrophysiology Procedures

"Intracardiac echocardiography (ICE) has evolved into an indispensable tool in the armamentarium of cardiac electrophysiologists not only for understanding the internal cardiac anatomy but also for establishing transseptal access and for monitoring electrophysiology procedures. ICE aids in live monitoring of every step of the procedure including early detection of complications. Access to the left atrium through transseptal catheterization is a vital step to perform atrial fibrillation and accessory pathway ablations, ablation of left ventricular tachycardias, left atrial appendage closures, left ventricular endocardial electrode implantations for cardiac resynchronization therapies, and for selectively sampling the regions of interest during endomyocardial biopsies."

Image Integration Using Intracardiac Echography and Three-dimensional Reconstruction for Mapping and Ablation of Atrial and Ventricular Arrhythmias

This article reviews the basis for image integration of intracardiac echocardiography (ICE) with three-dimensional electroanatomic mapping systems and preprocedural cardiac imaging modalities to enhance anatomic understanding and improve guidance for atrial and ventricular ablation procedures. It discusses the technical aspects of ICE-based integration and the clinical evidence for its use. In addition, it presents the current technical limitations and future directions for this technology. This article also includes figures and videos of clinical representative arrhythmia cases where the use of ICE is key to a safe and successful outcome.

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.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

Ventricular Tachycardia Storm Originating From Moderator Band Requiring Extracorporeal Membrane Oxygenation

A 67-year-old man presented with dizziness secondary to ventricular tachycardia (VT) originating from the moderator band. The VT was refractory to multiple antiarrhythmic medications requiring extracorporeal membrane oxygenation and eventual curative ablation. We highlight a malignant form of idiopathic VT, unique electrocardiogram characteristics, and ablation considerations. (Level of Difficulty: Intermediate.)

Successful cryoablation of ventricular extrasystoles originating from the vicinity of the left anterior fascicle

A 32‐year‐old male received catheter ablation of frequent ventricular extrasystoles (VEs). His electrocardiogram showed monomorphic VEs with an inferior axis and early precordial transitional zone. During electrophysiological testing, a 10‐pole catheter positioned in the left ventricular outflow tract recorded sharp pre‐potentials just before the ventricular activation during VEs as well as sinus beats. Three‐dimensional mapping was performed by annotating the sharp pre‐potentials to reveal that the earliest activation site was deemed to be close to the left anterior fascicle. A cryoablation catheter was introduced into the left ventricle and freezing for 240 seconds successfully eliminated the clinical VEs without any complications.

Ablation of Refractory Papillary Muscle Ventricular Tachycardia Warranting Multiple Adjunctive Ablation Techniques: A Combined Approach for Success

A 27-year-old male presented to our institution with recurrent unifocal premature ventricular contraction/nonsustained ventricular tachycardia (VT) with associated cardiomyopathy. The patient had undergone three prior ablation procedures with continued arrhythmia. Mapping led to identification of the VT arising from the basal aspect of the left ventricular anterolateral papillary muscle. Conventional ablation techniques were unsuccessful. We incorporated adjunctive ablation techniques in this case that ultimately led to a successful outcome. The present discussion covers the roles of intracardiac echocardiography, induced apnea, and low-ionic irrigation.

Ablation Therapy for Refractory Ventricular Arrhythmias

Recurrent ventricular arrhythmias (VAs) are a leading cause of cardiovascular morbidity and mortality. In the last three decades, important advancements have occurred in the understanding of the mechanisms of recurrent VAs, their prognostic implications in different clinical contexts, and their treatment options. VAs occur in structurally normal hearts as well as in patients with underlying heart disease, but the latter group has a particularly high risk of recurrent VAs. Catheter ablation offers the possibility of cure for a substantial proportion of patients. Research has focused on identifying optimal targets for ablation, correlating the underlying structural abnormalities with the site of origin of VAs, and determining the optimal procedural approach. Ablation therapy can be life-saving in select patients with high burden of repetitive VAs or advanced heart failure syndromes. This article focuses on clinical aspects of catheter ablation of VAs, particularly the selection and clinical management of patients undergoing catheter ablation procedures and expected outcomes.

Electrophysiological Substrates in Papillary Muscle Arrhythmias – Implications for Catheter Ablation

Collapse

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

Papillary muscle ventricular arrhythmias in patients with arrhythmic mitral valve prolapse: Electrophysiologic substrate and catheter ablation outcomes

BACKGROUND

Mitral valve prolapse (MVP) is a common valve condition and has been associated with sudden cardiac death. Premature ventricular contractions (PVCs) from the papillary muscles (PMs) may play a role as triggers for ventricular fibrillation (VF) in these patients.

OBJECTIVES

To characterize the electrophysiological substrate and outcomes of catheter ablation in patients with MVP and PM PVCs.

METHODS

Of 597 patients undergoing ablation of ventricular arrhythmias during the period 2012-2015, we identified 25 patients with MVP and PVCs mapped to the PMs (64% female). PVC-triggered VF was the presentation in 4 patients and a fifth patient died suddenly during follow-up. The left ventricle ejection fraction (LVEF) was 50.5% ± 11.8% and PVC burden was 24.4% ± 13.1%. A cardiac magnetic resonance imaging was performed in nine cases and areas of late gadolinium enhancement were found in four of them. A detailed LV voltage map was performed in 11 patients, three of which exhibited bipolar voltage abnormalities. Complete PVC elimination was achieved in 19 (76%) patients and a significant reduction in PVC burden was observed in two (8%). In patients in which the ablation was successful, the PVC burden decreased from 20.4% ± 10.8% to 6.3% ± 9.5% (P = 0.001). In 5/6 patients with depressed LVEF and successful ablation, the LV function improved postablation. No significant differences were identified between patients with and without VF.

CONCLUSIONS

PM PVCs are a source of VF in patients with MVP and can induce PVC-mediated cardiomyopathy that reverses after PVC suppression. Catheter ablation is highly successful with more than 80% PVC elimination or burden reduction.

Papillary Muscle Ventricular Tachycardia or Ectopy: Diagnostics, Catheter Ablation and the Role of Intracardiac Echocardiography

Ventricular arrhythmias originating from the papillary muscle of the left or right ventricle are specific clinical entities. They are usually focal in origin and can be identified by a characteristic ECG pattern. Intracardiac echocardiography appears to be the most suitable imaging method for assessment of the exact location of the focus at papillary muscles in association with activation mapping. We recently confirmed that ectopic foci were located within the distal, mid, or proximal (basal) third of the papillary muscle in 67%, 19%, and 14% of patients, respectively. Radiofrequency ablation has the potential to cure these specific arrhythmias. However, the procedure is usually challenging for catheter instability, despite navigation with intracardiac echocardiography. Cryoablation, which ensures catheter tip stability, could be a viable alternative in cases of the failure of radiofrequency catheter ablation.

Catheter Ablation of Idiopathic Ventricular Arrhythmias

Ventricular arrhythmias (VA) are observed in the setting of structural heart disease. However, in a proportion of patients presenting with VT, the routine diagnostic modalities fail to demonstrate overt myocardial abnormality. These arrhythmias have been called idiopathic VAs. They consist of various subtypes that have been defined by their anatomic location of origin within the heart and/or their underlying mechanism. While the majority of patients are asymptomatic, some experience debilitating symptoms and may develop reversible ventricular dysfunction. Catheter ablation has been traditionally reserved for patients with incapacitating symptoms or progressive ventricular dysfunction. However, as many patients are young, and catheter ablation can be curative in >90% of cases with a low risk (<1%) of serious complications, it is increasingly being offered as a first-line treatment in symptomatic patients. The approach to arrhythmia mapping is guided by the 12-lead electrocardiograph (ECG) morphology of the ventricular tachycardia (VT). Use of three dimensional (3D) electroanatomic mapping systems and intra-cardiac echocardiography are helpful in localising sites for successful ablation.