Complication rates following ventricular tachycardia ablation in ischaemic and non-ischaemic cardiomyopathies: a systematic review

Feasibility, Efficacy, and Safety of Fluoroless Ablation of VT in Patients With Structural Heart Disease

BACKGROUND

Catheter ablation of ventricular tachycardia (VT) typically requires radiation exposure with its potential adverse health effects. A completely fluoroless ablation approach is achievable using a combination of electroanatomical mapping and intracardiac echocardiography. Nonetheless, data in patients undergoing VT ablation are limited.

OBJECTIVES

This study aimed to determine the feasibility, efficacy, and safety of VT ablation in patients with structural heart disease using a zero-fluoroscopy approach.

METHODS

This multicenter study included consecutive patients with ischemic and nonischemic cardiomyopathy undergoing fluoroless VT ablation. Patients requiring epicardial access or coronary angiography were excluded.

RESULTS

Between 2017 and 2023 a total of 198 patients (aged 66.4 ± 13.4 years, 76% male, 48% ischemic) were included. Most patients (95.4%) underwent left ventricular (LV) mapping and/or ablation, which was conducted via transseptal route in 54.5% (n = 103), via retrograde aortic route in 43.4% (n = 82), and using a combined approach in 2.1% (n = 4). Two-thirds of patients had a cardiac device, including a biventricular device in 15%; 2 patients had a LV assist device, and 1 patient had a mechanical aortic valve prosthesis. The mean total procedural time was 211 ± 70 minutes, and the total radiofrequency time was 30 ± 22 minutes. During a follow-up period of 22 ± 18 months, the freedom from VT recurrence was 80%, and 7.6% of patients underwent a repeated ablation. Procedural-related complications occurred in 6 patients (3.0%).

CONCLUSIONS

Fluoroless ablation of VT in structural heart disease is feasible, effective, and safe when epicardial mapping/ablation is not required.

Radiation therapy for ventricular arrhythmias

Ventricular arrhythmias (VA) can be life-threatening arrhythmias that result in significant morbidity and mortality. Catheter ablation (CA) is an invasive treatment modality that can be effective in the treatment of VA where medications fail. Recurrence occurs commonly following CA due to an inability to deliver lesions of adequate depth to cauterise the electrical circuits that drive VA or reach areas of scar responsible for VA. Stereotactic body radiotherapy is a non-invasive treatment modality that allows volumetric delivery of energy to treat circuits that cannot be reached by CA. It overcomes the weaknesses of CA and has been successfully utilised in small clinical trials to treat refractory VA. This article summarises the current evidence for this novel treatment modality and the steps that will be required to bring it to the forefront of VA treatment.

Surpoint algorithm for improved guidance of ablation for ventricular tachycardia (SURFIRE-VT): A pilot study

INTRODUCTION

The utility of ablation index (AI) to guide ventricular tachycardia (VT) ablation in patients with structural heart disease is unknown. The aim of this study was to assess procedural characteristics and clinical outcomes achieved using AI-guided strategy (target value 550) or conventional non-AI-guided parameters in patients undergoing scar-related VT ablation.

METHODS

Consecutive patients (n = 103) undergoing initial VT ablation at a single center from 2017 to 2022 were evaluated. Patient groups were 1:1 propensity-matched for baseline characteristics. Single lesion characteristics for all 4707 lesions in the matched cohort (n = 74) were analyzed. The impact of ablation characteristics was assessed by linear regression and clinical outcomes were evaluated by Cox proportional hazard model.

RESULTS

After propensity-matching, baseline characteristics were well-balanced between AI (n = 37) and non-AI (n = 37) groups. Lesion sets were similar (scar homogenization [41% vs. 27%; p = .34], scar dechanneling [19% vs. 8%; p = .18], core isolation [5% vs. 11%; p = .4], linear and elimination late potentials/local abnormal ventricular activities [35% vs. 44%; p = .48], epicardial mapping/ablation [11% vs. 14%; p = .73]). AI-guided strategy had 21% lower procedure duration (-47.27 min, 95% confidence interval [CI] [-81.613, -12.928]; p = .008), 49% lower radiofrequency time per lesion (-13.707 s, 95% CI [-17.86, -9.555]; p < .001), 21% lower volume of fluid administered (1664 cc [1127, 2209] vs. 2126 cc [1750, 2593]; p = .005). Total radiofrequency duration (-339 s [-24%], 95%CI [-776, 62]; p = .09) and steam pops (-155.6%, 95% CI [19.8%, -330.9%]; p = .08) were nonsignificantly lower in the AI group. Acute procedural success (95% vs. 89%; p = .7) and VT recurrence (0.97, 95% CI [0.42-2.2]; p = .93) were similar for both groups. Lesion analysis (n = 4707) demonstrated a plateau in the magnitude of impedance drops once reaching an AI of 550-600.

CONCLUSION

In this pilot study, an AI-guided ablation strategy for scar-related VT resulted in shorter procedure time and average radiofrequency time per lesion with similar acute procedural and intermediate-term clinical outcomes to a non-AI-guided approach utilizing traditional ablation parameters.

Impact of age on hospital outcomes after catheter ablation for ventricular tachycardia

Background

The real-world data on the safety profile of ventricular tachycardia (VT) ablation among elderly patients is not well-established. This study aimed to evaluate the procedural outcomes among those aged 18-64 years versus those aged ≥65 years who underwent catheter ablation of VT.

Method

Using the Nationwide Readmissions Database, our study included patients aged ≥18 years who underwent VT catheter ablation between 2017 and 2020. We divided the patients into non-elderly (18-64 years old) and elderly age groups (≥65 years old). We then analyzed the in-hospital procedural outcome and 30-day readmission between these two groups.

Results

Our study included 2075 (49.1%) non-elderly patients and 2153 (50.9%) elderly patients who underwent VT ablation. Post-procedurally, elderly patients had significantly higher rates of prolonged index hospitalization (≥7 days; 35.5% vs. 29.3%, p < .01), non-home discharge (13.4% vs. 6.0%, p < .01), 30-day readmission (17.0% vs. 11.4%, p < .01), and early mortality (5.5% vs. 2.4%, p < .01). There was no significant difference in the procedural complications between two groups, namely vascular complications, hemopericardium/cardiac tamponade, cerebrovascular accident (CVA), major bleeding requiring blood transfusion, and systemic embolization. Through multivariable analysis, the elderly group was associated with higher odds of early mortality (OR: 7.50; CI 1.86-30.31, p = .01), non-home discharge (OR: 2.41; CI: 1.93-3.00, p < .01) and 30-day readmission (OR: 1.58; CI 1.32-1.89, p < .01).

Conclusion

Elderly patients have worse in-hospital outcome, early mortality, non-home discharge, and 30-day readmission following catheter ablation for VT. There was no significant difference between elderly and non-elderly groups in the procedural complications.

Cryocure-VT: the safety and effectiveness of ultra-low-temperature cryoablation of monomorphic ventricular tachycardia in patients with ischaemic and non-ischaemic cardiomyopathies

AIMS

The ultra-low-temperature cryoablation (ULTC) ablation system using -196°C N2 cryogen has been reported to create lesions with freeze duration-dependent depth titratable to over 10 mm with minimum attenuation by scar. Cryocure-VT (NCT04893317) was a first-in-human clinical trial evaluating the safety and efficacy of a novel, purpose-built ULTC catheter in endocardial ablation of scar-dependent ventricular tachycardias (VTs).

METHODS AND RESULTS

This prospective, multi-centre study enrolled patients referred for de novo or second ablations of recurrent monomorphic VT of both ischaemic and non-ischaemic aetiologies. Primary safety and efficacy endpoints of the study were freedom from device- or procedure-related major adverse events (MAEs) up to 30 days post-ablation, acute non-inducibility of clinical VTs at the end of the procedure, and freedom from sustained VT or implantable defibrillator intervention at 6 months. Ultra-low-temperature cryoablation was performed in 64 patients (age 67 ± 11 years, 78% ischaemic, ejection fraction = 35 ± 10%) at 9 centres. The primary acute effectiveness endpoint was achieved in 94% (51/54) of patients in whom post-ablation induction was attempted. There were no protocol-defined MAEs; four procedure-related serious adverse events resolved without clinical sequelae. At 6-month follow-up, 38 patients (60.3%) remained VT-free, and freedom from defibrillator shock was 81.0%, with no significant difference between ischaemic and non-ischaemic cohorts. In 47 patients with defibrillator for at least 6 months prior to the ablation, the VT burden was reduced from median of 4, inter-quartile range (IQR, 1-9) to 0, IQR (0-2).

CONCLUSION

In this first-in-human multi-centre experience, endocardial ULTC ablation of monomorphic VT appears safe and effective in patients with both ischaemic-cardiomyopathy and non-ischaemic-cardiomyopathy.

CLINICAL TRIAL REGISTRATION

NCT04893317.

Ultra-Low-Temperature Cryoablation for Ventricular Tachycardia: An Early Single-Centre Report of Acute Results

Background

Endocardial catheter ablation for ventricular tachycardia (VT) may fail because of the inability to deliver transmural lesions. Ultra-low-temperature cryoablation (ULTC) uses near-critical nitrogen and can generate temperatures as low as -196 °C. We report a series of 18 patients who underwent ULTC at the McGill University Health Centre (MUHC), representing the largest single-centre experience to date.

Methods

Eighteen patients with monomorphic drug-refractory VT underwent VT ablation with ULTC at our institution as part of the first-in-human CryoCure-VT trial (NCT04893317). After voltage map, the mapping catheter was replaced with the ULTC catheter, and lesions were applied over a fixed duration of time (60-180 seconds), followed by a 60-second thaw and another application at the original duration (freeze-thaw-freeze). Duration of ablation time was selected depending on the wall thickness of the left ventricle monitored with intracardiac echo to achieve tissue depths of 4.5 to 7.5 mm.

Results

Baseline left ventricular ejection fraction was 32%, mean age 71 years, 94% were male. A total of 32 sustained VTs were induced in 16 of 18 patients. A total of 177 cryoablation lesions were delivered (9.8 lesions per patient). Of the 16 patients with inducible VT, 15 (94%) were rendered noninducible postablation, and 1 was inducible only for a nonclinical VT. Complications included 1 pericardial effusion that required drainage. From 18 patients, 16 (89%) were discharged within the first 24 hours postablation.

Conclusions

ULTC is feasible and permits acute control of monomorphic VT during VT ablation procedures in drug-refractory patients.

Major in-hospital complications after catheter ablation of cardiac arrhythmias: individual case analysis of 43 031 procedures

AIMS

In-hospital complications of catheter ablation for atrial fibrillation (AF), atrial flutter (AFL), and ventricular tachycardia (VT) may be overestimated by analyses of administrative data.

METHODS AND RESULTS

We determined the incidences of in-hospital mortality, major bleeding, and stroke around AF, AFL, and VT ablations in four German tertiary centres between 2005 and 2020. All cases were coded by the G-DRG- and OPS-systems. Uniform code search terms were applied defining both the types of ablations for AF, AFL, and VT and the occurrence of major adverse events including femoral vascular complications, iatrogenic tamponade, stroke, and in-hospital death. Importantly, all complications were individually reviewed based on patient-level source records. Overall, 43 031 ablations were analysed (30 361 AF; 9364 AFL; 3306 VT). The number of ablations/year more than doubled from 2005 (n = 1569) to 2020 (n = 3317) with 3 times and 2.5 times more AF and VT ablations in 2020 (n = 2404 and n = 301, respectively) as compared to 2005 (n = 817 and n = 120, respectively), but a rather stable number of AFL ablations (n = 554 vs. n = 612). Major peri-procedural complications occurred in 594 (1.4%) patients. Complication rates were 1.1% (n = 325) for AF, 1.0% (n = 95) for AFL, and 5.3% (n = 175) for VT. With an increase in complex AF/VT procedures, the overall complication rate significantly increased (0.76% in 2005 vs. 1.81% in 2020; P = 0.004); but remained low over time. Following patient-adjudication, all in-hospital cardiac tamponades (0.7%) and strokes (0.2%) were related to ablation. Major femoral vascular complications requiring surgical intervention occurred in 0.4% of all patients. The in-hospital mortality rate adjudicated to be ablation-related was lower than the coded mortality rate: AF: 0.03% vs. 0.04%; AFL: 0.04% vs. 0.14%; VT: 0.42% vs. 1.48%.

CONCLUSION

Major adverse events are low and comparable after catheter ablation for AFL and AF (∼1.0%), whereas they are five times higher for VT ablations. In the presence of an increase in complex ablation procedures, a moderate but significant increase in overall complications from 2005-20 was observed. Individual case analysis demonstrated a lower than coded ablation-related in-hospital mortality. This highlights the importance of individual case adjudication when analysing administrative data.

Using real-world data from health systems to evaluate the safety and effectiveness of a catheter to treat ischemic ventricular tachycardia

BACKGROUND

The ThermoCool STSF catheter is used for ablation of ischemic ventricular tachycardia (VT) in routine clinical practice, although outcomes have not been studied and the catheter does not have Food and Drug Administration (FDA) approval for this indication. We used real-world health system data to evaluate its safety and effectiveness for this indication.

METHODS

Among patients undergoing ischemic VT ablation with the ThermoCool STSF catheter pooled across two health systems (Mercy Health and Mayo Clinic), the primary safety composite outcome of death, thromboembolic events, and procedural complications within 7 days was compared to a performance goal of 15%, which is twice the expected proportion of the primary composite safety outcome based on prior studies. The exploratory effectiveness outcome of rehospitalization for VT or heart failure or repeat VT ablation at up to 1 year was averaged across health systems among patients treated with the ThermoCool STSF vs. ST catheters.

RESULTS

Seventy total patients received ablation for ischemic VT using the ThermoCool STSF catheter. The primary safety composite outcome occurred in 3/70 (4.3%; 90% CI, 1.2-10.7%) patients, meeting the pre-specified performance goal, p = 0.0045. At 1 year, the effectiveness outcome risk difference (STSF-ST) at Mercy was - 0.4% (90% CI: - 25.2%, 24.3%) and at Mayo Clinic was 12.6% (90% CI: - 13.0%, 38.4%); the average risk difference across both institutions was 5.8% (90% CI: - 12.0, 23.7).

CONCLUSIONS

The ThermoCool STSF catheter was safe and appeared effective for ischemic VT ablation, supporting continued use of the catheter and informing possible FDA label expansion. Health system data hold promise for real-world safety and effectiveness evaluation of cardiovascular devices.

Complications of catheter ablation for ventricular tachycardia

With the increasing literature demonstrating benefits of catheter ablation for ventricular tachycardia (VT), the number of patients undergoing VT ablation has increased dramatically. As VT ablation is being performed more routinely, operators must be aware of potential complications of VT ablation. This review delves deeper into the practice of VT ablation with a focus on periprocedural complications.

Impact of early ventricular tachycardia ablation in patients with an implantable cardioverter-defibrillator: An updated systematic review and meta-analysis of randomized controlled trials

BACKGROUND

There is limited information on whether early catheter ablation (CA) for ventricular tachycardia (VT) is associated with better outcomes compared with alternative strategies in patients with implantable cardioverter-defibrillator (ICD).

OBJECTIVE

The purpose of this article was to assess the efficacy of early VT CA in patients with ICD.

METHODS

EMBASE, PubMed, and Cochrane were searched from inception to April 2022. Randomized controlled trials comparing the efficacy of early VT CA with control groups, both in patients with ICD, were included in the analysis. Data on effect estimates in individual studies were extracted and combined via random effects meta-analysis using the DerSimonian and Laird method, a generic inverse variance strategy.

RESULTS

Nine randomized controlled trials with 1106 patients (n = 1018, 92.1% with ischemic cardiomyopathy and n = 88, 7.9% with nonischemic cardiomyopathy) were evaluated. VT CA was associated with reduced VT recurrences (odds ratio [OR] 0.64; P = .007), appropriate ICD shocks (OR 0.53; P = .002), ICD therapies (OR 0.54; P = .002), and cardiovascular hospitalization (OR 0.67; P = .004). However, no significant differences were observed in terms of mortality rate, heart failure hospitalization, and quality of life between the early VT CA and control groups.

CONCLUSION

Early CA was beneficial in reducing VT burden and ICD therapies. However, it did not affect mortality rate and quality of life. Since most patients in the included studies presented with ischemic cardiomyopathy, further studies on nonischemic cardiomyopathy should be conducted to validate if early CA has similar outcomes.

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.