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

Economic Evaluations in Electrophysiology in the Last 15 Years: A Systematic Review of the Literature

Background

Electrophysiology (EP) procedures, including cardiac implantable electronic devices (CIEDs) and ablations, are widely used to manage arrhythmias and heart failure. These interventions, though effective, require substantial resources, prompting the need for systematic economic evaluations to inform healthcare decision-making.

Methods

A systematic review of studies from 2007 to 2024 was conducted in two phases. Phase one assessed trends in economic evaluations of EP procedures, analyzing 129 studies across regions and timeframes. Phase two focused on cost-effectiveness analyses of implantable cardioverter defibrillators (ICDs), cardiac resynchronization therapy defibrillators (CRT-Ds), and atrial fibrillation (AF) ablation, examining outcomes like quality-adjusted life years (QALYs) and incremental cost-effectiveness ratios (ICERs), while identifying factors influencing economic results.

Results

EP procedures generally demonstrated favorable cost-effectiveness, particularly in high-income regions. Studies on ICDs and CRT-Ds consistently supported their economic value for patients with arrhythmias or heart failure, while AF ablation showed potential for long-term benefits, particularly when compared to medical therapies. However, results varied by region, reflecting differences in healthcare systems, costs, and patient populations.

Conclusions

The review highlights the overall cost-effectiveness of EP procedures in many settings but underscores the need for tailored economic evaluations in low- and middle-income countries. Simplified methodologies and greater attention to regional contexts are recommended to guide resource allocation and policy development globally.

Outcomes of ventricular tachycardia ablation facilitated by pre-procedural cardiac imaging-derived scar characterization: a prospective multi-centre international registry

AIMS

Pre-procedural imaging can facilitate scar-related ventricular tachycardia (VT) ablation, although only limited data have been reported. This prospective registry aimed to analyse procedural data and outcomes in a multi-centre setting of a pre-defined VT ablation strategy facilitated by the integration of pre-procedural imaging into the navigation system.

METHODS AND RESULTS

Consecutive patients referred for scar-related left-sided VT ablation were prospectively enrolled at five European tertiary hospitals. Pre-procedural cardiac magnetic resonance (CMR)-derived scar maps and/or multi-detector computed tomography (MDCT)-derived wall thinning maps of the left ventricle (LV) were obtained and integrated into the navigation system. An endocardial or endoepicardial approach was chosen based on the scar distribution at pre-procedural imaging. The decision of performing a detailed electro-anatomical map (EAM) of the LV (image-aided) or to using the pre-procedural imaging for guiding the ablation without obtaining an EAM (image-guided) was left to the physician's discretion. One hundred and seventy-one patients (71% with ischaemic cardiomyopathy) were included. Cardiac magnetic resonance was integrated in 159 (93%), MDCT in 113 (66%), and both in 101 (59%) procedures. Procedure-related complications occurred in 9 (5%) patients. At a mean follow-up of 18 ± 19 months, the overall survival and VT recurrence-free survival were 91 and 74.4%, respectively. There were no significant differences in long-term ablation outcomes based on the type of cardiomyopathy (P = 0.88) or the pre-procedural imaging modality employed (P = 0.33). An image-guided approach appears feasible, safe, and faster, with reduced procedure, radiofrequency, and fluoroscopy times, without compromising efficacy.

CONCLUSION

In a large multi-centre prospective cohort, VT ablation facilitated by pre-procedural imaging is associated with favourable long-term outcomes.

Epicardial ventricular arrhythmia ablation: a clinical consensus statement of the European Heart Rhythm Association of the European Society of Cardiology and the Heart Rhythm Society, the Asian Pacific Heart Rhythm Society, the Latin American Heart Rhythm Society, and the Canadian Heart Rhythm Society

Epicardial access during electrophysiology procedures offers valuable insights and therapeutic options for managing ventricular arrhythmias (VAs). The current clinical consensus statement on epicardial VA ablation aims to provide clinicians with a comprehensive understanding of this complex clinical scenario. It offers structured advice and a systematic approach to patient management. Specific sections are devoted to anatomical considerations, criteria for epicardial access and mapping evaluation, methods of epicardial access, management of complications, training, and institutional requirements for epicardial VA ablation. This consensus is a joint effort of collaborating cardiac electrophysiology societies, including the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, the Latin American Heart Rhythm Society, and the Canadian Heart Rhythm Society.

Characterization of ventricular tachycardia ablation in end-stage heart failure patients with left ventricular assist device (CHANNELED registry)

AIMS

Patients with left ventricular assist devices (LVADs) are at high risk for ventricular tachycardia (VT), and data on VT ablation in patients with LVAD are scarce. This multicentre registry assessed the mechanism of VT, procedural parameters, and outcome of VT ablation in patients with LVAD (NCT06063811).

METHODS AND RESULTS

Data of patients with LVAD referred for VT ablation at nine tertiary care centres were collected retrospectively. Parameters included VT mechanisms, procedural data, VT recurrence, and mortality. Overall, 69 patients (90% male, mean age 60.7 ± 8.4 years) undergoing 72 ablation procedures were included. Most procedures were conducted after intensification of antiarrhythmic drug (AAD) treatment (18/72; 25%) or a prior combination of ≥2 AADs (31/72; 43%). Endocardial low-voltage areas were detected in all patients. The predominant VT mechanism was scar-related re-entry (76/96 VTs; 79%), and 19/96 VTs (20%) were related to the LVAD cannula. Non-inducibility of any VT was achieved in 28/72 procedures (39%). No LVAD-related complication was observed. The extent of endocardial scar was associated with VT recurrence. The median follow-up was 283 days (interquartile range 70-587 days). A total of 3/69 patients were lost to follow-up, 10/69 (14%) were transplanted, 26/69 (38%) died, and 16/69 (23%) patients were free from VT.

CONCLUSION

Although often a last resort, VT ablation in patients with LVAD is feasible and safe when performed in experienced centres. These patients suffer from a high scar burden, and cardiomyopathy-associated rather than cannula-related scar seems to be the dominant substrate. Ventricular tachycardia recurrence is high despite extensive treatment, and the overall prognosis is limited.

Evoked delayed potential ablation for post-myocardial infarction ventricular tachycardia: results from a large prospective multicentre study

AIMS

The optimal substrate ablation approach for post-myocardial infarction (MI) ventricular tachycardia (VT) is unknown. Proposed ablation targets are prone to individual interpretation making the ablation outcome potentially operator dependent. Evoked delayed potentials (EDPs) are a well-defined target. Evoked delayed potential ablation was effective in preventing post-MI VT recurrence in a prior study. The aims of this study were to assess long-term outcomes of EDP ablation in a large multicentre cohort of post-MI patients and to compare ablation outcomes between centres with and without prior experience in EDP ablation.

METHODS AND RESULTS

Patients with post-MI VT undergoing ablation in one centre performing EDP ablation since 2013 and five centres without prior experience in EDP ablation were prospectively included. A uniform mapping protocol including right ventricular extra-stimulation aiming to EDP identification was followed. Ablation endpoints were EDP elimination and VT non-inducibility. Patients were followed for VT recurrence, mortality, heart transplant, and left ventricular assist device implantation. In total, 130 patients were included. The protocol was successfully performed in 99%, and in 94%, EDPs were identified and ablated. In total, 78% of patients were rendered non-inducible. Ventricular tachycardia-free survival was 78% [95% confidence interval (CI) 71-85] and 71% (95% CI 63-80) at 6 and 12 months, respectively. No difference in VT-free survival was observed among centres with and without prior experience in EPD ablation.

CONCLUSION

In a large multicentre prospective cohort of patients with post-MI VT, EDP ablation resulted in good long-term outcomes. Importantly, VT recurrence rates did not differ among centres with and without prior experience in EDP ablation, indicating that this approach can be easily reproduced by operators previously not familiar with the technique.

Epicardial access for ventricular tachycardia and premature ventricular complexes ablation: An institutional experience

Background

Epicardial access for ventricular arrhythmia (VA) ablation is a challenging and relatively uncommon procedure during ventricular ablation.

Objective

This study aimed to assess the outcomes, predictors of success, and complications associated with pericardial access during these procedures.

Methods

This multicenter, retrospective, observational study included data collected over 20 years (2004-2024) from all Mayo Clinic sites performing VA ablation with epicardial access.

Results

A total of 265 patients were included in the analysis: 196 for VT ablation and 69 for PVC ablation. Among them, 184 (69%) had at least 1 previous VA ablation, 51 (19.2%) had ischemic cardiomyopathy, 53 (20%) had structurally normal hearts, and 164 (61.9%) had nonischemic cardiomyopathies (NICMs). Three presented with concomitant ischemic cardiomyopathy and NICM. Within the NICM group, the most common diagnoses were dilated cardiomyopathy (n = 80 [30.2%]), arrhythmogenic right ventricular cardiomyopathy (n = 34 [12.8%]), and sarcoidosis (n = 15 [5.7%]). Acute success, defined as noninducibility, was achieved in 100 (61.7%) of 162 patients tested, while partial success (clinical arrhythmia noninduciblility) was observed in 47 (29%). Before discharge, VT recurred in 20 patients (10.2%). During a median follow-up of 61 months, events were observed as follows: 60 (35.5%) patients died, 26 (13.3%) underwent heart transplantation, and 62 (31.6%) required a repeat ablation for VAs. The event-free survival rates were 50% (95% confidence interval 43%-58%) at 1 year.

Conclusion

Successful VT ablation with epicardial access can be achieved in select cases, though event-free survival remains suboptimal. Advanced disease stage and persistent inducibility at the end of the procedure are predictors of poor outcomes.

Ablation options for sub-epicardially located ventricular substrates responsible for ventricular tachycardia: where is it all headed?

PURPOSE OF REVIEW

Patients with nonischemic and ischemic cardiomyopathy (NICM and ICM) exhibit re-entrant tachycardias related to scar tissue in subepicardial, in addition to typical subendocardial locations. Control of ventricular arrhythmias related to these targets has remained elusive despite advances in mapping and ablation technology.

RECENT FINDINGS

Percutaneous epicardial ablation is the standard after failed endocardial ventricular ablation, but recurrence rates are disappointing. Pulsed-field energy has been associated with coronary artery spasm and therefore may be less suitable for epicardial ablation. Commercially available energy sources, including pulsed-field, have limited depths of myocardial penetration when applied epicardially. Lateral volumetric thermal spreading of ablation injury is associated with decreasing depth of ablation and is difficult to control. A new cryoablation technology based on liquid helium and developed specifically for epicardial work may be able to overcome these limitations.

SUMMARY

Ablation strategies that can improve lesion formation in subepicardial ventricular myocardium may improve outcomes of ablation in nonsubendocardial NICM and ICM targets.

Excellent Outcomes After First-Line Ablation in Post-MI Patients With Tolerated VT and LVEF >35

BACKGROUND

Post-myocardial infarction (MI) patients with ventricular tachycardia (VT) are considered at risk for VT recurrence and sudden cardiac death (SCD). Recent guidelines indicate that in selected patients catheter ablation should be considered instead of an implantable cardioverter-defibrillator (ICD).

OBJECTIVES

This study aimed to analyze outcomes of patients referred for VT ablation according to left ventricular ejection fraction (LVEF), tolerance of VT, and acute ablation outcome.

METHODS

Post-MI patients without prior ICD undergoing VT ablation at a single center between 2009 and 2022 were included. Patients who presented with tolerated VT and who had an LVEF >35% were offered catheter ablation as first-line therapy. ICD implantation was offered to all patients but was subject to shared decision according to clinical presentation, LVEF, and ablation outcome.

RESULTS

Eighty-six patients (mean age 69 ± 9 years, 84% male, mean LVEF 41 ± 9%) underwent VT ablation. In 66 patients, LVEF was >35%, of whom 51 had tolerated VT. Of these 51 patients, 37 (73%) were rendered noninducible. In 5 of 37 noninducible and in 11 of 14 inducible patients, an ICD was implanted. During a median follow-up of 40 months (Q1-Q3: 24-70 months), 10 of 86 patients had VT recurrence. The overall mortality was 27%, and 1 patient with ICD died suddenly. Among the 37 patients (none on antiarrhythmic drugs) with LVEF >35%, tolerated VT, and noninducibility, no SCD or VT recurrence occurred. Among the 14 patients with LVEF >35%, tolerated VT, and inducibility after ablation, no SCD occurred, but VT recurred in 29%.

CONCLUSIONS

Post-MI patients with LVEF >35%, tolerated VT, and noninducibility after ablation have an excellent prognosis. Deferring ICD implantation seems to be safe in these patients.

2024 updated European Heart Rhythm Association core curriculum for physicians and allied professionals: a statement of the European Heart Rhythm Association of the European Society of Cardiology

Heart rhythm management is a continuously evolving sub-speciality of cardiology. Every year, many physicians and allied professionals (APs) start and complete their training in cardiac implantable electronic devices (CIEDs) or electrophysiology (EP) across the European Heart Rhythm Association (EHRA) member countries. While this training ideally ends with an EHRA certification, the description of the learning pathway (what, how, when, and where) through an EHRA core curriculum is also a prerequisite for a successful training. The first EHRA core curriculum for physicians was published in 2009. Due to the huge developments in the field of EP and device therapy, this document needed updating. In addition, a certification process for APs has been introduced, as well as a recertification process and accreditation of EHRA recognized training centres. Learning pathways are more individualized now, with Objective Structured Assessment of Technical Skills (OSATS) to monitor learning progression of trainees. The 2024 updated EHRA core curriculum for physicians and APs describes, for both CIED and EP, the syllabus, OSATS, training programme and certification, and recertification for physicians and APs and stresses the importance of continued medical education after certification. In addition, requirements for accreditation of training centres and trainers are given. Finally, suggested reading lists for CIED and EP are attached as online supplements.

High-density isochronal repolarization mapping and re-entry vulnerability estimation for scar-related ventricular tachycardia ablation: mechanistic basis, clinical application, and challenges

Alterations in repolarization gradients and increased heterogeneity are key electrophysiological determinants of ventricular arrhythmogenesis across a variety of aetiologies with and without structural heart disease. High-density repolarization mapping to localize these repolarization abnormalities could improve characterization of the individual arrhythmogenic substrate and inform more targeted ablation. Yet, due to challenges posed by intrinsic features of human cardiac repolarization itself as well as technical and practical limitations, they are not routinely assessed, and traditional substrate mapping techniques remain strictly limited to determining conduction abnormalities. Here, we provide an overview of the mechanistic role of repolarization alterations in ventricular re-entry arrhythmias followed by a description of a clinical workflow that enables high-density repolarization mapping during ventricular tachycardia (VT) ablations using existing clinical tools. We describe step-by-step guidance of how-to set-up and generate repolarization maps illustrating the approach in case examples of structural normal and abnormal hearts. Furthermore, we discuss how repolarization mapping could be combined with existing substrate mapping approaches, including isochronal late activation mapping, to delineate sites of increased re-entry vulnerability, that may represent targets for ablation without the requirement for VT induction. Finally, we review challenges and pitfalls and ongoing controversies in relation to repolarization mapping and discuss the need for future technical and analytical improvements in repolarization mapping to integrate into ventricular substrate mapping strategies. Repolarization mapping remains investigational, and future research efforts need to be focused on prospective trials to establish the additional diagnostic value and its role in clinical ablation procedures.

Mapping and ablation of ventricular tachycardia using dual-energy lattice-tip focal catheter: early feasibility and safety study

AIMS

Catheter ablation is an effective treatment method for recurrent ventricular tachycardias (VTs). However, at least in part, procedural and clinical outcomes are limited by challenges in generating an adequate lesion size in the ventricular myocardium. We investigated procedural and clinical outcomes of VT ablation using a novel 'large-footprint' catheter that allows the creation of larger lesions either by radiofrequency (RF) or by pulsed field (PF) energy.

METHODS AND RESULTS

In prospectively collected case series, we describe our initial experience with VT ablation using a lattice-tip, dual-energy catheter (Sphere-9, Medtronic), and a compatible proprietary electroanatomical mapping system (Affera, Medtronic). The study population consisted of 18 patients (aged 55 ± 15 years, one woman, structural heart disease: 94%, ischaemic heart disease: 56%, left ventricular ejection fraction: 34 ± 10%, electrical storm: 22%) with recurrent sustained VTs and ≥1 previously failed endocardial RF ablation with conventional irrigated-tip catheter in 66% of patients. On average, 12 ± 7 RF and 8 ± 9 PF applications were delivered per patient. In three-fourths of patients undergoing percutaneous epicardial ablation, spasms in coronary angiography were observed after PF applications. All resolved after intracoronary administration of nitrates. No acute phrenic nerve palsy was noted. One patient suffered from a stroke that resolved without sequelae. Post-ablation non-inducibility of VT was achieved in 89% of patients. Ventricular-arrhythmia-free survival at three months was 78%.

CONCLUSION

VT ablation using a dual-energy lattice-tip catheter and a novel electroanatomical mapping system is feasible. It allows rapid mapping and effective substrate modification with good outcomes during short-term follow-up.

Detailed analysis of electrogram peak frequency to guide ventricular tachycardia substrate mapping

AIMS

Differentiating near-field (NF) and far-field (FF) electrograms (EGMs) is crucial in identifying critical arrhythmogenic substrate during ventricular tachycardia (VT) ablation. A novel algorithm annotates NF-fractionated signals enabling EGM peak frequency (PF) determination using wavelet transformation. This study evaluated the algorithms' effectiveness in identifying critical components of the VT circuit during substrate mapping.

METHODS AND RESULTS

A multicentre, international cohort undergoing VT ablation was investigated. VT activation maps were used to demarcate the isthmus zone (IZ). Offline analysis was performed to evaluate the diagnostic performance of low-voltage area (LVA) PF substrate mapping. A total of 30 patients encompassing 198 935 EGMs were included. The IZ PF was significantly higher in sinus rhythm (SR) compared to right ventricular paced (RVp) substrate maps (234 Hz (195-294) vs. 197 Hz (166-220); P = 0.010). Compared to LVA PF, the IZ PF was significantly higher in both SR and RVp substrate maps (area under curve, AUC: 0.74 and 0.70, respectively). The LVA PF threshold of ≥200 Hz was optimal in SR maps (sensitivity 69%; specificity 64%) and RVp maps (sensitivity 60%; specificity 64%) in identifying the VT isthmus. In amiodarone-treated patients (n = 20), the SR substrate map IZ PF was significantly lower (222 Hz (186-257) vs. 303 Hz (244-375), P = 0.009) compared to amiodarone-naïve patients (n = 10). The ≥200 Hz LVA PF threshold resulted in an 80% freedom from VT with a trend towards reduced ablation lesions and radiofrequency times.

CONCLUSION

LVA PF substrate mapping identifies critical components of the VT circuit with an optimal threshold of ≥200 Hz. Isthmus PF is influenced by chronic amiodarone therapy with lower values observed during RV pacing.

Bipolar radiofrequency ablation of refractory ventricular arrhythmias: results from a multicentre network

AIMS

Advanced ablation strategies are needed to treat ventricular tachycardia (VT) and premature ventricular complexes (PVC) refractory to standard unipolar radiofrequency ablation (Uni-RFA). Bipolar radiofrequency catheter ablation (Bi-RFA) has emerged as a treatment option for refractory VT and PVC. Multicentre registry data on the use of Bi-RFA in the setting of refractory VT and PVC are lacking. The aim of this Bi-RFA registry is to determine its real-world safety, feasibility, and efficacy in patients with refractory VT/PVC.

METHODS AND RESULTS

Consecutive patients undergoing Bi-RFA at 16 European centres for recurring VT/PVC after at least one standard Uni-RFA were included. Second ablation catheter was used instead of a dispersive patch and was positioned at the opposite site of the ablation target. Between March 2021 and August 2024, 91 patients underwent 94 Bi-RFA procedures (74 males, age 62 ± 13, and prior Uni-RFA range 1-8). Indications were recurrence of PVC (n = 56), VT (n = 20), electrical storm (n = 13), or PVC-triggered ventricular fibrillation (n = 2). Procedural time was 160 ± 73 min, Bi-RFA time 426 ± 286 s, and mean Uni-RFA time 819 ± 697 s. Elimination of clinical VT/PVC was achieved in 67 (74%) patients and suppression of VT/PVC in a further 10 (11%) patients. In the remaining 14 patients (15%), no effect on VT/PVC was observed. Three major complications occurred: coronary artery occlusion, atrioventricular block, and arteriovenous fistula. Follow-up lasted 7 ± 8 months. Nineteen patients (61%) remained VT free. ≥80% PVC burden reduction was achieved in 45 (78%).

CONCLUSION

These real-world registry data indicate that Bi-RFA appears safe, is feasible, and is effective in the majority of patients with VT/PVC.

Acute post-procedural inducibility is a poor predictor of clinical outcomes in high-risk patients (PAINESD > 17) undergoing scar-related ventricular tachycardia ablation

AIMS

Ventricular tachycardia (VT) non-inducibility in response to programmed ventricular stimulation (PVS) is a widely used procedural endpoint for VT ablation despite inconclusive evidence with respect to clinical outcomes in high-risk patients. The aim is to determine the utility of acute post-ablation VT inducibility as a predictor of VT recurrence, mortality, or mortality equivalent in high-risk patients.

METHODS AND RESULTS

We conducted a retrospective analysis of high-risk patients (defined as PAINESD > 17) who underwent scar-related VT ablation at our institution between July 2010 and July 2022. Patients' response to PVS (post-procedure) was categorized into three groups: Group A, no clinical VT or VT with cycle length > 240 ms inducible; Group B, only non-clinical VT with cycle length > 240 ms induced; and Group C, all other outcomes (including cases where no PVS was performed). The combined primary endpoint included death, durable left ventricular assist device placement, and cardiac transplant (Cox analysis). Ventricular tachycardia recurrence was considered a secondary endpoint (competing risk analysis). Of the 1677 VT ablation cases, 123 cases met the inclusion criteria for analysis. During a 19-month median follow-up time (interquartile range 4-43 months), 82 (66.7%) patients experienced the composite primary endpoint. There was no difference between Groups A and C with respect to the primary [hazard ratio (HR) = 1.21 (0.94-1.57), P = 0.145] or secondary [HR = 1.18 (0.91-1.54), P = 0.210] outcomes. These findings persisted after multivariate adjustments. The size of Group B (n = 13) did not permit meaningful statistical analysis.

CONCLUSION

The results of post-ablation PVS do not significantly correlate with long-term outcomes in high-risk (PAINESD > 17) VT ablation patients.

Periprocedural acute haemodynamic decompensation during substrate-based ablation of scar-related ventricular tachycardia: a rare and unpredictable event

AIMS

Patients with structural heart disease (SHD) undergoing catheter ablation (CA) for ventricular tachycardia (VT) are at considerable risk of periprocedural complications, including acute haemodynamic decompensation (AHD). The PAINESD score was proposed to predict the risk of AHD. The goal of this study was to validate the PAINESD score using the retrospective analysis of data from a large-volume heart centre.

METHODS AND RESULTS

Patients who had their first radiofrequency CA for SHD-related VT between August 2006 and December 2020 were included in the study. Procedures were mainly performed under conscious sedation. Substrate mapping/ablation was performed primarily during spontaneous rhythm or right ventricular pacing. A purposely established institutional registry for complications of invasive procedures was used to collect all periprocedural complications that were subsequently adjudicated using the source medical records. Acute haemodynamic decompensation triggered by CA procedure was defined as intraprocedural or early post-procedural (<12 h) development of acute pulmonary oedema or refractory hypotension requiring urgent intervention. The study cohort consisted of 1124 patients (age, 63 ± 13 years; males, 87%; ischaemic cardiomyopathy, 67%; electrical storm, 25%; New York Heart Association Class, 2.0 ± 1.0; left ventricular ejection fraction, 34 ± 12%; diabetes mellitus, 31%; chronic obstructive pulmonary disease, 12%). Their PAINESD score was 11.4 ± 6.6 (median, 12; interquartile range, 6-17). Acute haemodynamic decompensation complicated the CA procedure in 13/1124 = 1.2% patients and was not predicted by PAINESD score with AHD rates of 0.3, 1.8, and 1.1% in subgroups by previously published PAINESD terciles (<9, 9-14, and >14). However, the PAINESD score strongly predicted mortality during the follow-up.

CONCLUSION

Primarily substrate-based CA of SHD-related VT performed under conscious sedation is associated with a substantially lower rate of AHD than previously reported. The PAINESD score did not predict these events. The application of the PAINESD score to the selection of patients for pre-emptive mechanical circulatory support should be reconsidered.

Use of three-dimensional electroanatomic mapping for epicardial access: needle tracking, electrographic characteristics, and clinical application

AIMS

Pericardiocentesis is usually completed under fluoroscopy. The electroanatomic mapping (EAM) system allows visualizing puncture needle tip (NT) while displaying the electrogram recorded from NT, making it possible to obtain epicardial access (EA) independent of fluoroscopy. This study was designed to establish and validate a technique by which EA is obtained under guidance of three-dimensional (3D) EAM combined with NT electrogram.

METHODS AND RESULTS

3D shell of the heart was generated, and the NT was made trackable in the EAM system. Unipolar NT electrogram was continuously monitored. Penetration into pericardial sac was determined by an increase in NT potential amplitude and an injury current. A long guidewire of which the tip was also visible in the EAM system was advanced to confirm EA. Epicardial access was successfully obtained without complication in 13 pigs and 22 patients. In the animals, NT potential amplitude was 3.2 ± 1.0 mV when it was located in mediastinum, 5.2 ± 1.6 mV when in contact with fibrous pericardium, and 9.8 ± 2.8 mV after penetrating into pericardial sac (all P ≤ 0.001). In human subjects, it measured 1.54 ± 0.40 mV, 3.61 ± 1.08 mV, and 7.15 ± 2.88 mV, respectively (all P < 0.001). Fluoroscopy time decreased in every 4-5 cases (64 ± 15, 23 ± 17, and 0 s for animals 1-4, 5-8, 9-13, respectively, P = 0.01; 44 ± 23, 31 ± 18, 4±7 s for patients 1-7, 8-14, 15-22, respectively, P < 0.001). In five pigs and seven patients, EA was obtained without X-ray exposure.

CONCLUSION

By tracking NT in the 3D EAM system and continuously monitoring the NT electrogram, it is feasible and safe to obtain EA with minimum or no fluoroscopic guidance.

Impact of ventricular tachycardia ablation in subcutaneous implantable cardioverter defibrillator carriers: a multicentre, international analysis from the iSUSI project

AIMS

Catheter ablation (CA) of ventricular tachycardia (VT) has become an important tool to improve clinical outcomes in patients with appropriate transvenous implantable cardioverter defibrillator (ICD) shocks. The aim of our analysis was to test whether VT ablation (VTA) impacts long-term clinical outcomes even in subcutaneous ICD (S-ICD) carriers.

METHODS AND RESULTS

International Subcutaneous Implantable Cardioverter Defibrillator (iSUSI) registry patients who experienced either an ICD shock or a hospitalization for monomorphic VT were included in this analysis. Based on an eventual VTA after the index event, patients were divided into VTA+ vs. VTA- cohorts. Primary outcome of the study was the occurrence of a combination of device-related appropriate shocks, monomorphic VTs, and cardiovascular mortality. Secondary outcomes were addressed individually. Among n = 1661 iSUSI patients, n = 211 were included: n = 177 experiencing ICD shocks and n = 34 hospitalized for VT. No significant differences in baseline characteristics were observed. Both the crude and the yearly event rate of the primary outcome (5/59 and 3.8% yearly event rate VTA+ vs. 41/152 and 16.4% yearly event rate in the VTA-; log-rank: P value = 0.0013) and the cardiovascular mortality (1/59 and 0.7% yearly event rate VTA+ vs. 13/152 and 4.7% yearly event rate VTA-; log-rank P = 0.043) were significantly lower in the VTA + cohort. At multivariate analysis, VTA was the only variable remaining associated with a lower incidence of the primary outcome [adjusted hazard ratio 0.262 (0.100-0.681), P = 0.006].

CONCLUSION

In a real-world registry of S-ICD carriers, the combined study endpoint of arrhythmic events and cardiovascular mortality was lower in the patient cohort undergoing VTA at long-term follow-up.

CLINICALTRIALS.GOV IDENTIFIER

NCT0473876.

Area-weighted unipolar voltage to predict heart failure outcomes in patients with ischaemic cardiomyopathy and ventricular tachycardia

AIMS

Patients with ischaemic cardiomyopathy (ICM) referred for catheter ablation of ventricular tachycardia (VT) are at risk for end-stage heart failure (HF) due to adverse remodelling. Local unipolar voltages (UV) decrease with loss of viable myocardium. A UV parameter reflecting global viable myocardium may predict prognosis. We evaluate if a newly proposed parameter, area-weighted unipolar voltage (awUV), can predict HF-related outcomes [HFO; HF death/left ventricular (LV) assist device/heart transplant] in ICM.

METHODS AND RESULTS

From endocardial voltage maps of consecutive patients with ICM referred for VT ablation, awUV was calculated by weighted interpolation of local UV. Associations between clinical and mapping parameters and HFO were evaluated and validated in a second cohort. The derivation cohort consisted of 90 patients [age 68 ±8 years; LV ejection fraction (LVEF) 35% interquartile range (IQR) (24-40)] and validation cohort of 60 patients [age 67 ± 9, LVEF 39% IQR (29-45)]. In the derivation cohort, during a median follow-up of 45 months [IQR (34-83)], 36 (43%) patients died and 23 (26%) had HFO. Patients with HFO had lower awUV [4.51 IQR (3.69-5.31) vs. 7.03 IQR (6.08-9.2), P < 0.001]. A reduction in awUV [optimal awUV (5.58) cut-off determined by receiver operating characteristics analysis] was a strong predictor of HFO (3-year HFO survival 97% vs. 57%). The cut-off value was confirmed in the validation cohort (2-year HFO-free survival 96% vs. 60%).

CONCLUSION

The newly proposed parameter awUV, easily available from routine voltage mapping, may be useful at identifying ICM patients at high risk for HFO.

Management of ventricular tachycardias: insights on centre settings, procedural workflow, endpoints, and implementation of guidelines-results from an EHRA survey

Ventricular tachycardia (VT), and its occurrence, is still one of the main reasons for sudden cardiac death and, therefore, for increased mortality and morbidity foremost in patients with structural heart [Kahle A-K, Jungen C, Alken F-A, Scherschel K, Willems S, Pürerfellner H et al. Management of ventricular tachycardia in patients with ischaemic cardiomyopathy: contemporary armamentarium. Europace 2022;24:538-51]. Catheter ablation has become a safe and effective treatment option in patients with recurrent VT [Cronin EM, Bogun FM, Maury P, Peichl P, Chen M, Namboodiri N et al. 2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias. Heart Rhythm 2020;17:e2-154]. Previous and current guidelines provide guidance on indication for VT ablation and risk assessment and evaluation of underlying disease. However, no uniform recommendation is provided regarding procedural strategies, timing of ablation, and centre setting. Therefore, these specifics seem to differ largely, and recent data are sparse. This physician-based European Heart Rhythm Association survey aims to deliver insights on not only infrastructural settings but also procedural specifics, applied technologies, ablation strategies, and procedural endpoints. Therefore, these findings might deliver a real-world scenario of VT management and potentially are of guidance for other centres.

Prevention of venous thromboembolism in right heart-sided electrophysiological procedures: results of an European Heart Rhythm Association survey

Limited data are available regarding venous thromboembolism (VTE), specifically deep vein thrombosis (DVT) and pulmonary embolism (PE), following right-sided ablations and electrophysiological (EP) studies. Compared to left-sided procedures, no guidelines on antithrombotic management strategies for the prevention of DVT and PE are available. The main purpose of the present European Heart Rhythm Association (EHRA) survey is to report the current management of right-sided EP procedures, focusing on anticoagulation and prevention of VTE. An online survey was conducted using the EHRA infrastructure. A total of 244 participants answered a 19-items questionnaire on the periprocedural management of EP studies and right-sided catheter ablations. The right femoral vein is the most common access for EP studies and right-sided procedures. An ultrasound-guided approach is employed by more than 2/3 of respondents. Intravenous heparin is not commonly given by the majority of participants. About 1/3 of participants (34%) routinely prescribe VTE prophylaxis during (mostly aspirin and low molecular weight heparin) and 1/4 of respondents (25%) commonly prescribe VTE prophylaxis after discharge (mostly aspirin). Of note, respectively 13% and 9% of participants observed at least one DVT and one PE related to right-sided ablation or EP study within the last year in their center. The present survey shows that only a minority of operators routinely gives intraprocedural intravenous heparin and prescribes VTE prophylaxis after right-sided EP procedures. Compared to left-sided procedures like atrial fibrillation (AF) ablation, there are no consistent systematic antithrombotic management strategies.