Efficacy and safety of ventricular tachycardia ablation with mechanical circulatory support compared with substrate-based ablation techniques

Procedural Adaptations to Avoid Haemodynamic Instability During Catheter Ablation of Scar-related Ventricular Tachycardia

Classically, catheter ablation for scar-related ventricular tachycardia (VT) relied upon activation and entrainment mapping of induced VT. Advances in post-MI therapies have led to VTs that are faster and haemodynamically less stable, because of more heterogeneous myocardial fibrosis patterns. The PAINESD score is one means of identifying patients at highest risk for haemodynamic decompensation during attempted VT induction, who may, therefore, benefit from alternative ablation strategies. One strategy is to use temporary mechanical circulatory support, although this warrants formal assessment of cost-effectiveness. A second strategy is to minimise or avoid VT induction altogether by employing a family of 'substrate'-based approaches aimed at identifying VT isthmuses during sinus or paced rhythm. Substrate mapping techniques are diverse, and focus on the timing, morphology and amplitude of local ventricular electrograms - sometimes aided by advanced non-invasive cardiac imaging modalities. In this review, the evolution of VT ablation over time is discussed, with an emphasis on procedural adaptations to the challenge of haemodynamic instability.

Three-dimensional mapping, recording and ablation in simulated and induced ventricular tachyarrhythmias during mechanical circulatory support using the percutaneous heart pump

PURPOSE

Due to their internal rotating magnets, conventional impeller-driven percutaneous ventricular assist devices (PVADs) yield high-frequency electrogram artifact and electromagnetic interference (EMI) when used with magnetic-based 3D electroanatomic mapping systems. The new percutaneous heart pump (PHP; Abbott, Chicago, IL) is a 14-French, 5-L/min, impeller axial-flow PVAD with a novel design that utilizes an external motor.

METHODS

We evaluated the feasibility of 3D mapping and radiofrequency ablation (RFA) in vivo during PHP mechanical circulatory support (MCS) in simulated ventricular tachycardia (pacing at 300 ms) and ventricular flutter (VFL, pacing at 200 ms) and also during ventricular fibrillation (VF) in a porcine model. Anterograde (right ventricular), transseptal, retrograde, and epicardial right and left ventricular 3D mapping (EnSite/CARTO) and RFA were performed in 6 swine using high-density mapping and force-sensing RFA catheters (TactiCath/ThermoCool). Surface and intracardiac electrograms and 3D maps were analyzed for noise/interference with and without MCS using PHP in sinus rhythm and simulated VT/VFL and VF.

RESULTS

Mapping and RFA proved feasible in the presence of MCS using PHP. The mean arterial pressure in sinus rhythm was 55 ± 2 mmHg (baseline) and 84 ± 4 mmHg during MCS with PHP and well-maintained during simulated VT (73 ± 8 mmHg) and VFL (65 ± 2 mmHg) and even in VF (65 ± 5 mmHg). No electrogram noise/artifact, EMI, or 3D map distortions were observed during mapping/RFA with either of two mapping systems.

CONCLUSIONS

Endocardial and epicardial 3D mapping and RFA in the presence of PHP are feasible and offer significant MCS during simulated VT/VFL and VF. Furthermore, PHP yielded no electrogram noise/artifact, EMI, or 3D mapping distortions in conjunction with magnetic-based 3D mapping systems.

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.

Early de-cannulation from extracorporeal membrane oxygenation following ventricular tachycardia radiofrequency ablation

Objectives

Ventricular tachycardia ablation (VTA) with hemodynamic compromise presents a challenge. Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support allows the safe completion of the procedure. There are limited data regarding the safety of weaning off VA-ECMO at the end of the procedure. We report our experience with early VA-ECMO de-cannulation after VTA.

Materials and methods

All patients undergoing VA-ECMO-assisted VTA, between January 2013 and December 2020 at a large tertiary center were included. Clinical characteristics, history of arrhythmia, procedural details, and outcomes were collected. Patients weaned from VA-ECMO immediately at the end of the procedure were compared to those that were de-cannulated at a later time.

Results

A total of 46 patients (93.5% male, age 62 ± 10 years) were ablated with VA-ECMO support. Most had ischemic cardiomyopathy (65%) and (70%) presented with VT storm. The clinical VT was induced in the majority of patients (76%). A total of 99 VTs were induced of which 76 (77%) were targeted and successfully ablated. Non-inducibility was achieved in 74% of cases and most patients (83%) were de-cannulated at the end of the procedure on the procedure table. Survival at 1 year was higher among early de-cannulated patients (86 vs. 38% [log-rank p-value < 0.001]). At 1-year follow-up, 91.3% of surviving patients were free of appropriate ICD shocks.

Conclusion

De-cannulation from VA-ECMO may be done immediately at the conclusion of VTA in most cases. Failure to timely wean off VA-ECMO is a strong predictor of mortality.

Mechanical circulatory support in ventricular arrhythmias

In atrial and ventricular tachyarrhythmias, reduced time for ventricular filling and loss of atrial contribution lead to a significant reduction in cardiac output, resulting in cardiogenic shock. This may also occur during catheter ablation in 11% of overall procedures and is associated with increased mortality. Managing cardiogenic shock and (supra) ventricular arrhythmias is particularly challenging. Inotropic support may exacerbate tachyarrhythmias or accelerate heart rate; antiarrhythmic drugs often come with negative inotropic effects, and electrical reconversions may risk worsening circulatory failure or even cardiac arrest. The drop in native cardiac output during an arrhythmic storm can be partly covered by the insertion of percutaneous mechanical circulatory support (MCS) devices guaranteeing end-organ perfusion. This provides physicians a time window of stability to investigate the underlying cause of arrhythmia and allow proper therapeutic interventions (e.g., percutaneous coronary intervention and catheter ablation). Temporary MCS can be used in the case of overt hemodynamic decompensation or as a “preemptive strategy” to avoid circulatory instability during interventional cardiology procedures in high-risk patients. Despite the increasing use of MCS in cardiogenic shock and during catheter ablation procedures, the recommendation level is still low, considering the lack of large observational studies and randomized clinical trials. Therefore, the evidence on the timing and the kinds of MCS devices has also scarcely been investigated. In the current review, we discuss the available evidence in the literature and gaps in knowledge on the use of MCS devices in the setting of ventricular arrhythmias and arrhythmic storms, including a specific focus on pathophysiology and related therapies.

Cardiopulmonary Support During Catheter Ablation of Ventricular Arrhythmias With Hemodynamic Instability: The Role of Inducibility

Background: Catheter ablation is a treatment option for sustained ventricular tachycardias (VTs) that are refractory to pharmacological treatment; however, patients with fast VT and electrical storm (ES) are at risk for cardiogenic shock. We report our experience using cardiopulmonary support with extracorporeal membrane oxygenation (ECMO) during catheter ablation of VT. Methods: Sixty-two patients (mean age 68 ± 9 years; 94% male) were referred to our center for catheter ablation of repeated episodes of hemodynamically unstable ventricular arrhythmias. ES was defined as the occurrence of three or more VT/ventricular fibrillation episodes requiring electrical cardioversion or defibrillation in a 24-h period. All patients had hemodynamically unstable VTs. Results: Thirty-one patients (group 1) performed catheter ablation without ECMO support and 31 patients (group 2) with ECMO support. At the end of the procedure, ventricular inducibility was not performed in 16 patients of group 1 (52%) due to significant hemodynamic instability. Ventricular inducibility was performed in the other 15 patients (48%); polymorphic VTs were inducible in eight patients. In group 2, VTs were not inducible in 29 patients (93%); polymorphic VTs were inducible in two patients. The median follow-up duration was 24 months. Four patients of group 1 (13%) and five patients of group 2 (16%) died due to refractory heart failure. An implantable cardioverter-defibrillator intervention (shock or antitachycardia pacing) was documented in 13 patients of group 1 (42%) and six patients of group 2 (19%). Conclusions: Extracorporeal membrane oxygenation support during catheter ablation for hemodynamically unstable VTs is a useful tool to prevent acute procedural heart failure and to reduce arrhythmic burden.

HFA of the ESC Position paper on the management of LVAD supported patients for the non LVAD specialist healthcare provider Part 1: Introduction and at the non-hospital settings in the community

The accepted use of left ventricular assist device (LVAD) technology as a good alternative for the treatment of patients with advanced heart failure together with the improved survival of the LVAD‐supported patients on the device and the scarcity of donor hearts has significantly increased the population of LVAD‐supported patients. The expected and non‐expected device‐related and patient–device interaction complications impose a significant burden on the medical system exceeding the capacity of the LVAD implanting centres. The ageing of the LVAD‐supported patients, mainly those supported with the ‘destination therapy’ indication, increases the risk for those patients to experience comorbidities common in the older population. The probability of an LVAD‐supported patient presenting with medical emergency to a local emergency department, internal, or surgical ward of a non‐LVAD implanting centre is increasing. The purpose of this trilogy is to supply the immediate tools needed by the non‐LVAD specialized physician: ambulance clinicians, emergency ward physicians, general cardiologists, internists, anaesthesiologists, and surgeons, to comply with the medical needs of this fast‐growing population of LVAD‐supported patients. The different issues discussed will follow the patient's pathway from the ambulance to the emergency department and from the emergency department to the internal or surgical wards and eventually to the discharge home from the hospital back to the general practitioner. In this first part of the trilogy on the management of LVAD‐supported patients for the non‐LVAD specialist healthcare provider, after the introduction on the assist devices technology in general, definitions and structured approach to the assessment of the LVAD‐supported patient in the ambulance and emergency department is presented including cardiopulmonary resuscitation for LVAD‐supported patients.

Guidance on the management of left ventricular assist device (LVAD) supported patients for the non-LVAD specialist healthcare provider: executive summary

The accepted use of left ventricular assist device (LVAD) technology as a good alternative for the treatment of patients with advanced heart failure together with the improved survival of patients on the device and the scarcity of donor hearts has significantly increased the population of LVAD supported patients. Device-related, and patient-device interaction complications impose a significant burden on the medical system exceeding the capacity of LVAD implanting centres. The probability of an LVAD supported patient presenting with medical emergency to a local ambulance team, emergency department medical team and internal or surgical wards in a non-LVAD implanting centre is increasing. The purpose of this paper is to supply the immediate tools needed by the non-LVAD specialized physician - ambulance clinicians, emergency ward physicians, general cardiologists, and internists - to comply with the medical needs of this fast-growing population of LVAD supported patients. The different issues discussed will follow the patient's pathway from the ambulance to the emergency department, and from the emergency department to the internal or surgical wards and eventually back to the general practitioner.

Prophylactic mechanical circulatory support for protected ventricular tachycardia ablation: A meta-analysis of the literature

Acute hemodynamic decompensation (AHD) during ventricular tachycardia (VT) ablation occurs in about 11% of cases. Prophylactic use of temporary mechanical circulatory support (pro-tMCS) has been applied to prevent AHD during VT ablation, but evidence supporting this practice is still lacking. This systematic review and meta-analysis assessed the procedural characteristics and outcomes of pro-tMCS for VT ablation. PubMed/Medline was screened until February 2020. Articles including adults receiving pro-tMCS for VT ablation were included, and a meta-analysis to compare proMCS and no-tMCS was performed. Primary outcome was in-hospital/30-day mortality. Five observational studies presenting 400 procedures (pro-tMCS: n = 187; no-tMCS: n = 213) were included. Baseline characteristics were comparable between groups. Impella and TandemHeart were used in 86.6% and 13.4% of cases, respectively. In the pro-tMCS group, more VTs were induced (mean difference: 0.52, confidence interval [CI]: 0.26-0.77, P < .0001), and patients remained in VT on average for 24.04 minutes longer (CI: 18.28-29.80, P < .00001). Procedural success was comparable between groups, as was VT recurrence. Pro-tMCS patients had an odds ratio of 0.55 (CI: 0.28-1.05, P = .07) for in-hospital/30-day mortality and 0.55 (CI: 0.32-0.94, P = .03) for mortality at follow-up. Sixty-four percent of no-tMCS patients received rescue tMCS. The most common tMCS-related complications were bleeding events. Pro-tMCS allowed for a prolonged time on VTs and the induction of more VTs. Although these advantages were not associated with differences in procedural success, VT recurrence, or in-hospital/30-day mortality in the overall population, pro-tMCS might improve long-term survival. Further prospective studies are urgently needed to confirm these results.

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

Background

Catheter ablation of ventricular tachycardia (VT) is associated with potential major complications, including mortality. The risk of acute complications in patients with ischaemic cardiomyopathy (ICM) and non-ischaemic cardiomyopathy (NICM) has not been systematically evaluated.

Methods

PubMed was searched for studies of catheter ablation of VT published between September 2009 and September 2019. Pre-specified primary outcomes were (1) rate of major acute complications, including death, and (2) mortality rate.

Results

A total of 7395 references were evaluated for relevance. From this, 50 studies with a total of 3833 patients undergoing 4319 VT ablation procedures fulfilled the inclusion criteria (mean age 59 years; male 82%; 2363 [62%] ICM; 1470 [38%] NICM). The overall major complication rate in ICM cohorts was 9.4% (95% CI, 8.1–10.7) and NICM cohorts was 7.1% (95% CI, 6.0–8.3). Reported complication rates were highly variable between studies (ICM I² = 90%; NICM I² = 89%). Vascular complications (ICM 2.5% [95% CI, 1.9–3.1]; NICM 1.2% [95% CI, 0.7–1.7]) and cerebrovascular events (ICM 0.5% [95% CI, 0.2–0.7]; NICM, 0.1% [95% CI, 0–0.2]) were significantly higher in ICM cohorts. Acute mortality rates in the ICM and NICM cohorts were low (ICM 0.9% [95% CI, 0.5–1.3]; NICM 0.6% [95% CI, 0.3–1.0]) with the majority of overall deaths (ICM 75%; NICM 80%) due to either recurrent VT or cardiogenic shock.

Conclusion

Overall acute complication rates of VT ablation are comparable between ICM and NICM patients. However, the pattern and predictors of complications vary depending on the underlying cardiomyopathy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10840-021-00948-6.

Mechanical circulatory support in the management of life-threatening arrhythmia

Life-threatening refractory unstable ventricular arrhythmias in presence of advanced heart failure (HF) may determine haemodynamic impairment. Haemodynamic mechanical support (HMS) in this setting has a relevant role to restore end-organ perfusion. Catheter ablation (CA) of ventricular tachycardia (VT) is effective at achieving rhythm stabilization, allowing patient's weaning from HMS, or bridging to permanent HF treatments. Acute heart decompensation during CA at anaesthesia induction in presence of advanced heart disease, in selected cases requires a preemptive HMS to prevent periprocedure adverse outcomes. Substrate ablation during sinus rhythm (SR) might be an effective strategy of ablation in presence of unstable VTs; however, in a minority of patients, it might have some limitations and might be unfeasible in some settings, including the case of the mechanical induction of several unstable VTs and the absence of ablation targets. In case of the persistent induction of unstable VTs after a previous failure of a substrate-based ablation in SR, a feasible alternative strategy of ablation might be VT activation/entrainment mapping supported by HMS. Multiple devices are available for HMS in the low-output states related to electrical storm and during CA of VT. The choice of the device is not standardized and it is based on the centres' expertise. The aim of this article is to provide an up-to-date review on HMS for the management of life-threatening arrhythmias, in the context of catheter ablation and discussing our approach to manage critical VT patients.

Ventricular Tachycardia Storm Ablation With Pre-Emptive Circulatory Support by Extracorporeal Membrane Oxygenation: Australian Experience

BACKGROUND

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) can provide circulatory support in high-risk patients undergoing drug refractory ventricular tachycardia (VT) ablation procedures. We report experience using VA-ECMO in a pre-emptive approach for high-risk patients with VT storm and previously ineffective ablation procedures.

METHODS AND RESULTS

Four (4) patients with drug refractory ventricular tachycardia (mean age 61±3 years; left ventricular ejection fraction 21±5%) presenting for VT ablation had pre-emptive VA-ECMO. All patients during current admission had VT storm. Pre-ablation, 22 total monomorphic VTs (cycle length 402±69 ms) were induced or spontaneously observed (median of 4, IQR_25-75% 1-6). At the end of the procedure, 86% of all inducible VTs were rendered non-inducible. Median hospitalisation following VA-ECMO supported ablation was 5 days (IQR_25-75% 3-12). During follow-up (median 138 days [IQR_25-75% 57-277]), VT recurred in one patient as an isolated episode reverted by anti-tachycardia pacing. There was a 99% reduction in VT burden post ablation. One (1) patient died of cardiogenic shock within 24 hours whilst still on VA-ECMO, all other patients were successfully weaned off support and discharged. Two (2) patients underwent cardiac transplantation at 199 and 512 days post ablation following implantation of ventricular assist devices for worsening heart failure.

CONCLUSIONS

The pre-emptive use of VA-ECMO for high-risk patients undergoing catheter ablation for VT storm was found to be effective in maintaining haemodynamic status, and allowing successful mapping and catheter ablation for VT.

Mapping and Ablation of Unmappable Ventricular Tachycardia, Ventricular Tachycardia Storm, and Those in Acute Myocardial Infarction

In stable ventricular tachycardia (VT), activation mapping and entrainment mapping are the most important strategies to describe the reentrant circuit and its critical components. In many patients, however, VT is noninducible or hemodynamically unstable and unmappable. Several technological advances have broadened ablation options in unmappable VTs. Preprocedural imaging and intraprocedural imaging play an important role in location and extent of the substrate. Electroanatomic mapping with several technological improvements allows more precise electrical assessment of the substrate. A combination of imaging and electroanatomic mapping allows substantial modification of arrhythmogenic substrate in sinus rhythm or during device pacing without hemodynamic compromise.

Substrate Mapping and Ablation for Ventricular Tachycardia in Patients with Structural Heart Disease: How to Identify Ventricular Tachycardia Substrate

Catheter ablation for ventricular tachycardia (VT) has been increasingly used over the past two decades in patients with structural heart disease (SHD). In these individuals, a substrate mapping strategy is being more commonly applied to identify targets for VT ablation, which has been shown to be more effective versus targeting mappable VTs alone. There are a number of substrate mapping methods in existence that aim to explore potential VT isthmuses, although their success rates vary. Most of the reported electrogram-based mapping studies have been performed with ablation catheters; meanwhile, the use of multipolar mapping catheters with smaller electrodes and closer interelectrode spacing has emerged, which allows for an assessment of detailed near-field abnormal electrograms at a higher resolution. Another recent advancement has occurred in the use of imaging techniques in VT ablation, particularly in refining the substrate. The goal of this paper is to review the key developments and limitations of current mapping strategies of substrate-based VT ablation and their outcomes. In addition, we briefly summarize the role of cardiac imaging in delineating VT substrate.

Percutaneous left ventricular assist device support during ablation of ventricular tachycardia: A meta-analysis of current evidence

INTRODUCTION

Catheter ablation of ventricular tachycardia (VT) can be an effective therapy to reduce VT burden, but often it is limited by the potential for hemodynamic instability. Percutaneous left ventricular assist devices (pLVADs) have been used to maintain hemodynamic support during VT ablation but the evidence regarding its clinical impact has been inconclusive.

METHODS AND RESULTS

We sought to assess the clinical impact of pLVAD when used in VT ablation by conducting a meta-analysis of the current evidence. We searched Pubmed and found nine observational studies that compared clinical outcomes of VT ablation in patients with pLVAD support to controls with no pLVAD support. The pooled data did not show a significant difference in mortality between both groups, nor a difference in acute procedural success or in recurrence of VT. There was also no difference in the number of patients receiving a cardiac transplant or being enrolled in the transplant list. Although there was no difference in the ablation time between the groups, patients in the pLVAD group had a longer total procedural time and more procedure-related adverse effects.

CONCLUSION

This meta-analysis did not show clinical benefits from using pLVAD support during VT ablation, whereas it was associated with longer procedure times and more complications. This study was, however, limited by the observational nature of the data. In view of these data, the risk and benefit of pLVAD support during VT ablation should be considered on an individual basis.

Percutaneous left ventricular assist device vs . intra‐aortic balloon pump in patients with severe left ventricular dysfunction undergoing cardiovascular intervention: A meta‐analysis

Objective

Although controversial, the intra-aortic balloon pump (IABP) and percutaneous left ventricular assist device (PLVAD) are widely used for initial hemodynamic stabilization. We performed a meta-analysis to compare the clinical outcomes of these two devices in patients with severe left ventricular (LV) dysfunction undergoing percutaneous coronary intervention (PCI) or ventricular tachycardia (VT) ablation.

Methods

MEDLINE, EMBASE, the Cochrane Registry of Controlled Trials, and reference lists of relevant articles were searched. We included randomized controlled trials (RCTs) and prospective observational studies. Meta-analysis was conducted using a random effects model.

Results

The quantitative analysis included 4 RCTs and 2 observational studies. A total of 348 patients received PLVAD and 340 received IABP. Meta-analysis revealed that early mortality rates (in-hospital or 30-day) did not differ between the PLVAD and IABP groups (relative risk (RR) = 1.03, 95% confidence interval (CI) = 0.70–1.51, P = 0.89). Significant differences were observed between the two groups in the composite, in-hospital, non-major adverse cardiac and cerebrovascular events (MACCE) rate (RR = 1.30, 95% CI = 1.01–1.68, P = 0.04).

Conclusions

Compared with IABP, PLVAD with active circulatory support did not improve early survival in those with severe left ventricular dysfunction undergoing either PCI or VT ablation, but increased the in-hospital non-MACCE rate.

Percutaneous ventricular assist device in ventricular tachycardia ablation: a systematic review and meta-analysis

BACKGROUND

There is a lack of compelling data regarding the benefit of percutaneous ventricular assist devices (PVAD) in patients undergoing ventricular tachycardia (VT) ablation. The study aims to conduct a meta-analysis comparing the safety and efficacy of PVAD versus no-PVAD (N-PVAD) during VT ablation.

METHODS

Studies meeting criteria were systematically reviewed. Baseline characteristics and clinical outcomes were extracted and analyzed. A meta-analysis was performed using random-effects model to calculate risk ratio (RR) and mean difference (MD) with 95% confidence interval (CI).

RESULTS

The meta-analysis included five retrospective, observational studies consisting of 2026 patients (PVAD group-284 patients versus N-PVAD group-1742 patients). The PVAD group was sicker with significantly higher VT storm, lower LVEF and greater proportion of NYHA class ≥ III than N-PVAD (p < 0.050). The acute procedural success [RR 0.95, 95% CI, (0.89-1.00), p = 0.070], VT recurrence [RR 0.94, 95% CI, (0.66-1.34), p = 0.740] and mortality [RR 1.28, 95% CI, (0.43-3.83), p = 0.660] were similar on follow-up between PVAD versus N-PVAD. PVAD group also had significantly higher complications [RR 1.83, 95% CI (1.21-2.76), p = 0.004] and longer fluoroscopy [MD + 7.31 min, 95% CI (0.91-13.71), p = 0.030] and procedure time [MD + 71.41 min, 95% CI (31.67-111.14), p < 0.001] than N-PVAD.

CONCLUSION

Patients receiving PVAD support during VT ablation were sicker with no significant difference in acute procedural success, VT recurrence, and mortality compared with N-PVAD. PVAD support was also associated with higher complications and longer fluoroscopy and procedure time. A prospective randomized controlled trial will identify if using PVAD support in unstable patients undergoing VT ablation will impact clinical outcomes.

Mechanical Circulatory Support During Catheter Ablation of Ventricular Tachycardia: Indications and Options

Mapping of scar-related ventricular tachycardia (VT) in structural heart disease is fundamentally driven by identifying the critical isthmus of conduction that supports re-entry in and around myocardial scar. Mapping can be performed using activation and entrainment techniques during VT, or by substrate mapping performed in stable sinus or paced rhythm. Activation and entrainment mapping requires the patient to be in continuous VT, which may not be haemodynamically tolerated, or, if tolerated, may lead to adverse sequelae related to impaired end organ perfusion. Mechanical circulatory support (MCS) devices may facilitate haemodynamic stability and preserve end organ perfusion during sustained VT to permit mapping for long periods. Available options for haemodynamic support include an intra-aortic balloon pump (IABP), TandemHeart left atrial to femoral artery bypass system (CardiacAssist Inc., Pittsburgh, PA, USA), Impella left ventricle (LV) to aorta flow-assist system (Abiomed, Danvers, MA, USA), and extracorporeal membrane oxygenation (ECMO); the bypass and assist devices provide far better augmentation of cardiac output than IABP. MCS has potential key advantages including maintenance of vital organ perfusion, reduction of intra-cardiac filling pressures, reduction of LV volumes, wall stress, and myocardial consumption of oxygen, and improvement of coronary perfusion during prolonged periods of VT induction and/or mapping. Observational studies show MCS allows for longer duration of mapping, and increased likelihood of VT termination, without an increased risk of peri-procedural mortality or VT recurrence in follow-up, despite being used in a significantly sicker cohort of patients. However, MCS has increased risk of complications related to vascular access, bleeding, thromboembolic risk, mapping system interference, increase procedural complexity and increased cost. Acute haemodynamic decompensation occurs in ∼11% of patients undergoing VT ablation, and is associated with increased mortality. Prospectively identifying patients at risk of acute haemodynamic decompensation in the peri-procedural period may allow prophylactic MCS. Although observational studies of MCS in patients at high risk of haemodynamic decompensation are encouraging, its benefit needs to be proven in randomised trials. This review will summarise the indication for MCS, forms of MCS, procedural outcomes, complications and utility of MCS during VT ablation.

Hemodynamic Support in Ventricular Tachycardia Ablation: An International VT Ablation Center Collaborative Group Study

OBJECTIVES

This study sought to evaluate the clinical outcomes of patients receiving hemodynamic support (HS) during ventricular tacchycardia (VT) ablation.

BACKGROUND

There are limited real-world data evaluating its effect of HS in ablation outcomes.

METHODS

An analysis of 1,655 patients from the International VT Ablation Center Collaborative group was performed. A total of 105 patients received HS with percutaneous ventricular assist device.

RESULTS

Patients in the HS group had lower left ventricular ejection fraction (LVEF), higher New York Heart Association (NYHA) functional class, and more implantable cardioverter-defibrillator (ICD) shocks, VT storm, and antiarrhythmic drug use (all p < 0.05). The HS group also required significantly longer fluoroscopy, procedure, and total lesion time. Acute procedural success (71.8% vs. 73.7%; p = 0.04) was significantly lower and complications (12.5% vs. 6.5%; p = 0.03) and 1-year mortality (34.7% vs. 9.3%; p < 0.001) were significantly higher in the HS group. Multivariate Cox regression analysis demonstrated HS as an independent predictor of mortality (hazard ratio: 5.01; 95% confidence interval: 3.44 to 7.20; p < 0.001). There was no significant difference in VT recurrence between groups. In a subgroup analysis including LVEF ≤20% and NYHA functional class III to IV patients, acute procedural success (74.0% vs. 70.5%; p = 0.8), complications (15.6% vs. 7.8%; p = 0.2), VT recurrence (30.2% vs. 38.1%; p = 0.44), and 1-year mortality (40.0% vs. 28.8%; p = 0.2) were no different between the HS and no-HS groups.

CONCLUSIONS

Patients requiring HS were sicker with multiple comorbidities and, as expected, had a significantly higher 1-year mortality than did those patients in the no-HS group. In patients with LVEF ≤20% and NYHA functional class III to IV, there was also no significant difference in clinical outcomes when compared with no HS. Further studies are needed to systematically evaluate patients undergoing VT ablation receiving HS.

Outcomes of Ventricular Tachycardia Ablation Using Percutaneous Left Ventricular Assist Devices

Background—

Although percutaneous left ventricular assist devices (pLVADs) facilitate mapping and ablation of hemodynamically unstable ventricular tachycardia (VT), there is limited data whether clinical outcomes are improved. We sought to retrospectively compare the outcomes of patients undergoing scar-related VT ablation with and without pLVAD support.

Methods and Results—

The study population comprised 194 patients (109 pLVAD and 85 non-pLVAD). The pLVAD group more often had dilated cardiomyopathy (33% versus 13%; P =0.001), New York Heart Association heart failure class ≥III (51% versus 25%; P <0.001), lower left ventricular ejection fractions (26±10% versus 39±16%; P <0.001), and electrical storm (49% versus 34%; P =0.04). Procedure times (422±112 versus 330±92 minutes; P <0.001), postablation VT inducibility (20% versus 7%; P =0.02), and length of subsequent hospitalization (median 6 versus 4 days; P =0.001) were all higher in the pLVAD group. During median follow-up of 215 days, the primary end point (recurrent VT, heart transplantation, or death) occurred in 36% of the pLVAD versus 26% of the non-pLVAD groups ( P =0.14). After propensity matching for differences between groups, no differences were seen between groups for both acute procedural outcomes and the primary end point.

Conclusions—

In this large single-center scar-related VT ablation experience, despite the worse clinical status of the patients selected for pLVAD support, clinical outcomes were better than expected and were similar to healthier patients not receiving hemodynamic support. Patients with dilated cardiomyopathy presenting with electrical storm, advanced heart failure, and severe left ventricular dysfunction most frequently received hemodynamic support during VT ablation.

Hemodynamic Support for Ventricular Tachycardia Ablation

This review discusses the role of hemodynamic support for catheter ablation of unstable ventricular tachycardia, using commercially available mechanical circulatory support devices (intra-aortic balloon pump, Impella, TandemHeart, extracorporeal membrane oxygenation) and analyzes the published clinical experience of the safety and efficacy of these devices during ventricular tachycardia ablation. Appropriate selection of patients, device-specific characteristics, and hemodynamic monitoring is also discussed.

The Role of Intravenous Dopamine on Hemodynamic Support during Radiofrequency Catheter Ablation of Poorly Tolerated Idiopathic Ventricular Tachycardia

Background and Objectives

Hemodynamically unstable idiopathic ventricular tachycardias (VTs) are a challenge for activation or entrainment mapping technique. Mechanical circulatory support is an option, but is not always readily available. In this study, we investigated the safety and efficacy of hemodynamic support using intravenous (IV) dopamine solely during radiofrequency catheter ablation (RFCA) of hemodynamically unstable VT.

Subjects and Methods

Seven out of 86 patients with hemodynamically unstable idiopathic VT underwent de novo RFCA using dopamine in our single center. They were included in the study and reviewed retrospectively to investigate the procedural characteristics and outcomes.

Results

All patients were male, and the mean age was 50.7±5.3 years. One patient had implantable cardioverter-defibrillator for the secondary prevention. No evidence of myocardial ischemia was found in all patients. During the procedure, the mean blood pressure during VT without dopamine was 52.3±4.1 mmHg and increased to 82.6±3.8 mmHg after administering dopamine (Δ28.8±3.2 mmHg; total average dopamine dosage was 1266.1±389.6 mcg/kg). In all patients, activation mapping was safely applied, and VTs were terminated during energy delivery. Non-inducibility of clinical VT was achieved in all cases. There was no evidence of deterioration due to hypoperfusion during the peri-procedural period. No recurrence of ventricular tachyarrhythmias was observed in any of the patients, during a median follow-up of 23.0±6.1 months.

Conclusion

Hemodynamic support using IV dopamine during RFCA of hemodynamically unstable idiopathic VT facilitated detailed mapping to guide successful ablation.

Extracorporeal Membrane Oxygenation for Hemodynamic Support of Ventricular Tachycardia Ablation

Background—

We report the experience in a cohort of consecutive patients receiving extracorporeal membrane oxygenation during catheter ablation of unstable ventricular tachycardia (VT) at our center.

Methods and Results—

From 2010 to 2015, extracorporeal membrane oxygenation was initiated in 64 patients (average age: 63±15 years; left ventricular ejection fraction in 27±9%; cardiogenic shock in 23%, and electrical storm in 62% of patients) undergoing 74 unstable VT catheter ablation procedures. At least one VT was terminated in 81% of procedures with baseline inducible VT, and VT noninducibility was achieved in 69%. Acute heart failure occurred in 5 patients: 3 underwent emergency heart transplantation, 1 had left ventricular assist device (LVAD) implantation, and 1 patient eventually died because of subsequent mesenteric ischemia. All other patients were discharged alive. After a median follow-up of 21 months (13–28 months), VT recurrence was 33%; overall survival was 56 out of 64 patients (88%). Extracorporeal membrane oxygenation–supported ablation was the bridge to LVAD in 6.9% and to heart transplantation in 3.5% of patients. VT recurrence was related to ablation success (after 180 days of follow up: 19% when VT was noninducible, 42% if nonclinical VT was inducible, 75% when clinical VT was inducible, and 75% in untested patients, P <0.001). Incidence of all-cause death, heart transplantation, and LVAD was independently related to ablation outcome (at 180 days of follow-up: 9% when noninducibility was achieved, 50% in case of inducible VT, and 75% in untested patients, P <0.001). At multivariable analyses, noninducibility (hazard ratio 0.198; P =0.001) and left ventricular ejection fraction (hazard ratio 0.916; P =0.008) correlated with all-cause death, LVAD, and heart transplantation.

Conclusions—

Ablation of unstable VTs can be safely supported by extracorporeal membrane oxygenation, which allows rhythm stabilization with low procedure mortality, bridging decompensated patients to permanent LVAD or heart transplantation. Successful ablation is associated with better outcomes than unsuccessful ablation.

Anesthetic Management in Radiofrequency Catheter Ablation of Ventricular Tachycardia

Radiofrequency catheter ablation is increasingly being used to treat patients who have ventricular tachycardia, and anesthesiologists frequently manage their perioperative care. This narrative review is intended to familiarize anesthesiologists with preprocedural, intraprocedural, and postprocedural implications of this ablation. Ventricular tachycardia typically arises from structural heart disease, most often from scar tissue after myocardial infarction. Many patients thus affected will benefit from radiofrequency catheter ablation in the electrophysiology laboratory to ablate the foci of arrhythmogenesis. The pathophysiology of ventricular tachycardia is complex, as are the technical aspects of mapping and ablating these arrhythmias. Patients often have substantial comorbidities and tenuous hemodynamic status, necessitating pharmacologic and mechanical cardiopulmonary support. General anesthesia and monitored anesthesia care, when used for sedation during ablation, can lead to drug interactions and side effects in the presence of ventricular tachycardia, so anesthesiologists should also be aware of potential perioperative complications. We discuss variables that can help anesthesiologists safely guide patients through the challenges of radiofrequency catheter ablation of ventricular tachycardia.

Substrate-Based Ablation Versus Ablation Guided by Activation and Entrainment Mapping for Ventricular Tachycardia: A Systematic Review and Meta-Analysis

INTRODUCTION

Substrate-based ablation for scar-related ventricular tachycardia (VT) has gained prominence: however, there is limited data comparing it to ablation guided predominantly by activation and entrainment mapping of inducible and hemodynamically tolerated VTs. We compared the acute procedural efficacy and outcomes of predominantly substrate-based ablation versus ablation guided predominantly by activation and entrainment mapping.

METHODS AND RESULTS

Database searches through April 2016 identified 6 eligible studies (enrolling 403 patients, with 1 randomized study) comparing the 2 strategies. The relative risk of VT recurrence at follow-up was assessed as the primary outcome using a random-effects meta-analysis. Secondary endpoints of acute success (based on noninducibility of VT), procedural complications, and mortality were assessed using weighted mean difference with the random effects model. At a median follow-up of 18 months, the relative risk (RR) of VT recurrence was not significantly different with substrate-based versus activation/entrainment guided VT ablation (0.72, 95% confidence interval [CI] 0.44-1.18), P = 0.2). Acute success (RR 1.02, 95% CI 0.95-1.1, P = 0.6), procedural complications (RR 0.8, 95% CI 0.35-1.82, P = 0.5) cardiovascular mortality and total mortality did not differ significantly (RR 0.83, 95% CI 0.38-1.79, P = 0.6 and RR 0.76, 95% CI 0.36-1.59, P = 0.5, respectively).

CONCLUSIONS

This meta-analysis demonstrates similar acute procedural efficacy, and complications, VT recurrence and mortality rates when comparing a predominantly substrate-based ablation strategy to a strategy guided predominantly by activation and entrainment mapping of inducible and hemodynamically tolerated VTs.

Outcomes of pre-emptive and rescue use of percutaneous left ventricular assist device in patients with structural heart disease undergoing catheter ablation of ventricular tachycardia

PURPOSE

Patient selection and timing of percutaneous left ventricular assist device (pLVAD) insertion for maximal benefit during ventricular tachycardia (VT) ablation is not well defined. We aimed to assess the outcomes of pre-emptive and rescue use of pLVAD during VT ablation in patients with ischemic and non-ischemic cardiomyopathy.

METHODS

Between January 2009 and October 2011, 93 patients underwent VT ablation. Three groups were compared: (1) Rescue group (n = 12)-patients who required emergent pLVAD insertion due to hemodynamic collapse during VT ablation, (2) Pre-emptive group (n = 24)-patients who had pre-ablation pLVAD insertion, and (3) Non-pLVAD group (n = 57)-patients who did not undergo pLVAD insertion. Procedural outcomes including 30-day mortality were compared.

RESULTS

Thirty-day mortality was higher in the Rescue group compared to the Pre-emptive group (58 vs. 4 %, p = 0.003) and non-pLVAD (58 vs. 3 %, p = 0.001) group. There was no significant difference in 30-day mortality or long-term freedom of VT between the pre-emptive and non-pLVAD groups.

CONCLUSIONS

Despite rescue pLVAD insertion, hemodynamic collapse during VT ablation is associated with a persistently high 30-day mortality. Further studies are warranted to predict hemodynamic collapse and to refine the role of pLVAD in this setting.

Impella LD microaxial pump supporting combined mitral and coronary surgery in a patient with dilated cardiomyopathy. A short bridge to recovery?

Cardiac surgeons have to face the problem of impaired left ventricle function in patients undergoing routine valve or coronary procedures. The intra-aortic balloon pump is not always effective in preventing cardiac failure. The idea of using a microaxial rotating pump as a short-term perioperative support seems to be a convenient solution. The case of a patient with dilated cardiomyopathy undergoing combined mitral and coronary surgery with elective use of the Impella LD pump is presented. Various options of applying the Impella device are discussed, especially as a bridge to transplant or bridge to recovery.

Temporary mechanical circulatory support: a review of the options, indications, and outcomes

Cardiogenic shock remains a challenging disease entity and is associated with significant morbidity and mortality. Temporary mechanical circulatory support (MCS) can be implemented in an acute setting to stabilize acutely ill patients with cardiomyopathy in a variety of clinical situations. Currently, several options exist for temporary MCS. We review the indications, contraindications, clinical applications, and evidences for a variety of temporary circulatory support options, including the intra-aortic balloon pump (IABP), extracorporeal membrane oxygenation (ECMO), CentriMag blood pump, and percutaneous ventricular assist devices (pVADs), specifically the TandemHeart and Impella.

Compatibility of electroanatomical mapping systems with a concurrent percutaneous axial flow ventricular assist device

BACKGROUND

Hemodynamic instability hinders activation and entrainment mapping during ventricular tachycardia ablation. The Impella 2.5 microaxial flow device (MFD; Abiomed Inc., Danvers, MA, USA) is used to prevent hemodynamic instability during electrophysiologic study. However, electromagnetic interference (EMI) generated by this device can preclude accurate electroanatomic mapping.

METHODS

Impella was placed in the left ventricle of 7 canines for circulatory support. Electroanatomic mapping during sinus rhythm, ventricular pacing, and ventricular fibrillation (VF) was performed using magnet- (CARTO3, Biosense Webster Inc., Diamond Bar, CA, USA) and impedance- (EnSite Velocity System/EnSite NavX, St. Jude Medical Inc., St. Paul, MN, USA) based systems. Distance from device to points with severe EMI precluding acquisition was compared to points with mild/no EMI. Two methods were used to reduce EMI: (1) titration of MFD performance, and (2) impedance-only mapping combined with manual annotation of activation.

RESULTS

Severe EMI did not occur during impedance-based mapping. Severe EMI was observed using CARTO3 at 9.4% of all points attempted at maximum performance level (P8) of device. Severe EMI occurred at points closer to device (40.1 ± 16.8 mm) versus (55.5 ± 20.0 mm) for mild/no EMI, P < 0.0001. Severe EMI using CARTO3 was resolved by either (1) reduction of performance from P8 to P6 or (2) impedance-only mapping with manual annotation.

CONCLUSION

Concurrent use of MFD caused EMI to prevent acquisition of points with magnet-based mapping. Predictors for EMI were distance from device and performance level. Temporary reductions to P6 or impedance-only mapping are 2 methods to resolve EMI.

Percutaneous left ventricular assist devices in ventricular tachycardia ablation: multicenter experience

BACKGROUND

Data on relative safety, efficacy, and role of different percutaneous left ventricular assist devices for hemodynamic support during the ventricular tachycardia (VT) ablation procedure are limited.

METHODS AND RESULTS

We performed a multicenter, observational study from a prospective registry including all consecutive patients (N=66) undergoing VT ablation with a percutaneous left ventricular assist devices in 6 centers in the United States. Patients with intra-aortic balloon pump (IABP group; N=22) were compared with patients with either an Impella or a TandemHeart device (non-IABP group; N=44). There were no significant differences in the baseline characteristics between both the groups. In non-IABP group (1) more patients could undergo entrainment/activation mapping (82% versus 59%; P=0.046), (2) more number of unstable VTs could be mapped and ablated per patient (1.05±0.78 versus 0.32±0.48; P<0.001), (3) more number of VTs could be terminated by ablation (1.59±1.0 versus 0.91±0.81; P=0.007), and (4) fewer VTs were terminated with rescue shocks (1.9±2.2 versus 3.0±1.5; P=0.049) when compared with IABP group. Complications of the procedure trended to be more in the non-IABP group when compared with those in the IABP group (32% versus 14%; P=0.143). Intermediate term outcomes (mortality and VT recurrence) during 12±5-month follow-up were not different between both groups. Left ventricular ejection fraction ≤15% was a strong and independent predictor of in-hospital mortality (53% versus 4%; P<0.001).

CONCLUSIONS

Impella and TandemHeart use in VT ablation facilitates extensive activation mapping of several unstable VTs and requires fewer rescue shocks during the procedure when compared with using IABP.

VT ablation: New Developments and Approaches

OPINION STATEMENT

Over the past decade, catheter ablation has emerged as an important therapeutic option for ventricular tachycardia (VT) in both patients with and without structural heart disease. In patients without structural heart disease, catheter ablation serves as sole therapy for the treatment of VT. For those with structural heart disease, VT ablation has generally been reserved for patients who experience ICD therapies, and particularly those who fail antiarrhythmic agents. With the growing number of patients with implantable devices as well as improvements in heart failure therapy resulting in improved survival among ICD patients, the overall number of patients needing therapy for VT continues to increase. The past years have witnessed significant advances in our understanding of the arrhythmic substrate in various cardiomyopathies, resulting in substrate-based approaches for targeted VT ablation. Further, the growth in better technologies and techniques for VT ablation, such as the use of percutaneous epicardial ablation, the innovation of multielectrode catheters for rapid mapping, the use of intracardiac echocardiography (ICE) for mapping unusual sites, and activation and entrainment mapping of previously unmappable VTs assisted by mechanical circulatory support devices, has overcome the limitations and greatly improved the success rates of catheter ablation. This review summarizes recent advances and novel approaches in both technology and techniques for catheter ablation of ventricular tachycardia.

Catheter ablation of ventricular arrhythmias: targets, tactics, and tools

PURPOSE OF REVIEW

Drug-refractory ventricular tachycardia in the setting of structural heart disease results in frequent implantable cardioverter defibrillator therapies and an increased risk of heart failure. Management requires catheter ablation procedures for effective suppression of the arrhythmia.

RECENT FINDINGS

Imaging and electroanatomic mapping technologies provide new insights into the myocardial structural abnormalities responsible for ventricular tachycardia. Integration of imaging data with three-dimensional mapping systems coupled with improved targeting of abnormal electrical signals may improve the ablation outcomes. New ablation tools show promise for the effective ablation of previously unreachable myocardial ventricular tachycardia circuits.

SUMMARY

Catheter ablation procedures have evolved over the last 2 decades. Improved technology may contribute to more widespread utilization of catheter ablation in the future.

High-density substrate-guided ventricular tachycardia ablation: role of activation mapping in an attempt to improve procedural effectiveness

BACKGROUND

Advanced techniques of electroanatomical mapping efficiently guide ventricular tachycardia (VT) ablation strategies; in this context, the adjunctive value of combining activation mapping (AMap) to improve accuracy has not been elucidated.

OBJECTIVE

To investigate whether conventional AMap further contributes to the identification of critical sites of VT reentry and whether this translates into a more effective ablation outcome in a cohort of patients undergoing VT ablation.

METHODS

We prospectively enrolled 126 patients (mean age 65.3 ± 10.5 years; left ventricular ejection fraction 33.3% ± 7.2%) with ischemic (n = 89) or idiopathic (n = 37) dilated cardiomyopathy undergoing endocardial (n = 105) or endo-epicardial (n = 21) electroanatomical mapping and ablation. A substrate-guided strategy targeting surrogate markers of reentry was accomplished in all patients, but the feasibility and efficacy of AMap was preliminarily assessed for all induced VTs focusing on early VT suppression obtained during radiofrequency delivery. VT-free survival was assessed by ICD interrogation.

RESULTS

AMap successfully guided ablation in 62 of 104 (59.6%) patients with inducible VT(s). At 1 year, 6 of 126 (4.8%) patients died; VT recurred in 28 of 126 (22.2%) patients. No significant difference in VT recurrence rate was observed between patients in whom AMap proved effective versus those in whom substrate-guided ablation was not corroborated by AMap (16 of 62 [25.8%] vs 12 of 64 [18.8%]; log-rank test, P = .3).

CONCLUSIONS

Our findings support the efficacy of a substrate-guided strategy targeting specific markers of arrhythmogenicity identified during sinus rhythm. AMap proves highly efficient acutely but does not improve overall VT-free survival, suggesting that in patients with advanced cardiac disease, life-threatening arrhythmias can be successfully treated by ablation in sinus rhythm, thus limiting procedural risks.

Percutaneous hemodynamic support with Impella 2.5 during scar-related ventricular tachycardia ablation (PERMIT 1)

BACKGROUND

Percutaneous left ventricular assist devices (pLVADs) are increasingly being used to facilitate ablation of unstable ventricular tachycardia (VT), but the safety profile and hemodynamic benefits of these devices have not been described in a systematic, prospective manner.

METHODS AND RESULTS

Twenty patients with scar VT underwent ablation with a pLVAD. Neuromonitoring using cerebral oximetry was performed to evaluate a cerebral desaturation threshold to guide the duration of activation/entrainment mapping. The efficacy of pLVAD support was tested in a controlled manner with simulated VT. Complete procedural success was achieved in 50% (n=8) of patients, who were initially inducible for sustained VT, and partial procedural success in 37% (n=6). Using a cerebral desaturation level of 55% as a lower safety limit to guide the duration of sustained VT, 3 patients (15%) developed mild acute kidney injury (all resolved), and 1 (5%) patient developed mild cognitive dysfunction. During fast simulated VT (300 ms), cerebral desaturation to ≤55% occurred in more than half (53%) of patients tested without pLVAD support, compared with only 5% with full pLVAD support (P=0.003).

CONCLUSIONS

In a consecutive series of patients with severe left ventricular dysfunction, pLVAD-supported scar VT ablation was safe and feasible. During fast simulated VT, a miniaturized axial flow pump imparted a more favorable hemodynamic profile compared with pharmacological agents alone. Cerebral oximetry is a complimentary monitoring modality during scar VT ablation, and avoidance of cerebral desaturations below a threshold of 55% may safely guide the duration of mapping during unstable VT.