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

Percutaneous mechanical support in catheter ablation of ventricular arrhythmias: hype or hope?

Catheter ablation (CA) has become an established treatment strategy for managing recurrent ventricular tachycardias (VTs) in patients with structural heart disease. In recent years, percutaneous mechanical circulatory support (PMCS) devices have been increasingly used intra-operatively to improve the ablation outcome. One indication would be rescue therapy for patients who develop haemodynamic deterioration during the ablation. However, more efforts are focused on identifying subjects who are at high risk of such deterioration and could benefit from the pre-emptive use of the PMCS. The third reason to use PMCS could be the inability to identify diffuse substrate, especially in non-ischaemic cardiomyopathy. This paper reviews available experiences using various types of PMCS in different clinical scenarios. Although PMCS allows mapping during VT, it does not significantly influence acute outcomes and not convincingly long-term outcomes. On the contrary, the complication rate appears to be higher in PMCS cohorts. Our data suggest that even in patients with severe left ventricular dysfunction, the substrate modification can be performed without the need for general anaesthesia and risk of haemodynamic decompensation. In end-stage heart failure associated with the electrical storm, implantation of a left ventricular assist device (or PMCS with a transition to the left ventricular assist device) might be the preferred strategy before CA. In high-risk patients who are not potential candidates for these treatment options, radiotherapy could be considered as a bail-out treatment of recurrent VTs. These approaches should be studied in prospective trials.

Mechanical Support Strategies for High-Risk Procedures in the Invasive Cardiac Catheterization Laboratory: A State-of-the-Art Review

Thanks to advancements in percutaneous cardiac interventions, an expanding patient population now qualifies for treatment through percutaneous endovascular procedures. High-risk interventions far exceed coronary interventions and include transcatheter aortic valve replacement, endovascular management of acute pulmonary embolism and ventricular tachycardia ablation. Given the frequent impairment of ventricular function in these patients, frequently deteriorating during percutaneous interventions, it is hypothesized that mechanical ventricular support may improve periprocedural survival and subsequently patient outcome. In this narrative review, we aimed to provide the relevant evidence found for the clinical use of percutaneous mechanical circulatory support (pMCS). We searched the Pubmed database for articles related to pMCS and to pMCS and invasive cath lab procedures. The articles and their references were evaluated for relevance. We provide an overview of the clinically relevant evidence for intra-aortic balloon pump, Impella, TandemHeart and ECMO and their role as pMCS in high-risk percutaneous coronary intervention, transcatheter valvular procedures, ablations and high-risk pulmonary embolism. We found that the right choice of periprocedural pMCS could provide a solution for the hemodynamic challenges during these procedures. However, to enhance the understanding of the safety and effectiveness of pMCS devices in an often high-risk population, more randomized research is needed.

Experience in applied veno-arterial extracorporeal membrane oxygenation to support catheter ablation of malignant ventricular tachycardia

Background

An electrical storm due to malignant ventricular tachycardia (VT) is a life-threatening condition that requires catheter ablation (CA). Most VT arrhythmias evolve over time after acute myocardial infarction, coronary artery bypass grafting, or chronic heart failure. Clinically, only radiofrequency ablation can identify and block all arrhythmia origin points. The procedure necessitates continuous VT induction in patients, resulting in hemodynamic instability; therefore, extracorporeal membrane oxygenation (ECMO) support is required. Earlier studies have reported substantial mortality rates; however, our results are significantly more favorable. In this study, we combined the minimally invasive extracorporeal circulation (MiECC) approach with ECMO to preserve an appropriate ECMO flow rate, thus reducing intraoperative left heart afterload. We report 21 cases illustrating the usefulness of modified veno-arterial (VA)-ECMO in this scenario.

Methods

Data of 21 patients supported by the modified VA-ECMO system (MiECC approach combined with the ECMO system) during VT CA in the Wuhan Asia Heart Hospital between June 2020 and July 2021 were reviewed retrospectively.

Results

Successful ablation was achieved in 20 out of 21 patients (95%). The median time for ECMO implantation was 206 min. Only two patients experienced complications post-treatment. All patients made complete recovery and were discharged. All patients were alive at the 1-year-follow-up.

Conclusions

Our modified VA-ECMO system helped restore systemic circulation in patients experiencing an electrical storm, thus achieving greater electrical stability during VT CA. Pre-insertion of VA-ECMO can achieve even better results.

Minimal invasive extracorporeal circulation an alternative to ECMO in ventricular tachycardia ablation

BACKGROUND

The advantages of mechanical assistance during ventricular tachycardia (VT) ablation have not been clinically demonstrated. We propose and discuss a technique, set up by us, that makes use of minimally invasive extra-corporeal circulation (MiECC) type III associated with a venous reservoir system, which allows complete cardiac flow support and blood oxygenation as well as hemodynamic stability during long-lasting procedures.

METHODS

We present a retrospective case series of ten patients with valvular heart disease and unresponsive Ventricular Tachycardia (VT) who underwent VT ablation with MiECC support. The mean age of the patients was 72 ± 8 years and the left ventricular ejection fraction was 36 ± 12%. All patients underwent a clinical evaluation to identify the cause of VT unresponsiveness (e.g., ischemic heart disease).

RESULTS

A total of 140 min, the following parameters were evaluated and recorded for 140 min. Central venous pressure (CVP) was used to evaluate excess volume. During the first 5 min, the mean was 15 mmHg, with a pump flow of 1.5 L/min and a mean systemic arterial pressure of 100 mmHg while setting up the circulation support. Following drainage in a volumetric bag of 1 L of blood, CVP was reduced to a value of 5 mmHg with a flow rate of 5 L/min and a mean systemic arterial pressure of 65 mmHg. In the case of small and low-weight patients our "1 L protocol" can be modified.

CONCLUSIONS

In this preliminary retrospective case series, the MiECC type III system may represent the ideal support system during VT ablation, and further studies are needed to support this preliminary report.

Noninvasive neurological monitoring to enhance pLVAD-assisted ventricular tachycardia ablation - a Mini review

For critically ill patients, hemodynamic fluctuations can be life-threatening; this is particularly true for patients experiencing cardiac comorbidities. Patients may suffer from problems with heart contractility and rate, vascular tone, and intravascular volume, resulting in hemodynamic instability. Unsurprisingly, hemodynamic support provides a crucial and specific benefit during percutaneous ablation of ventricular tachycardia (VT). Mapping, understanding, and treating the arrhythmia during sustained VT without hemodynamic support is often infeasible due to patient hemodynamic collapse. Substrate mapping in sinus rhythm can be successful for VT ablation, but there are limitations to this approach. Patients with nonischemic cardiomyopathy may present for ablation without exhibiting useful endocardial and/or epicardial substrate-based ablation targets, either due to diffuse extent or a lack of identifiable substrate. This leaves activation mapping during ongoing VT as the only viable diagnostic strategy. By enhancing cardiac output, percutaneous left ventricular assist devices (pLVAD) may facilitate conditions for mapping that would otherwise be incompatible with survival. However, the optimal mean arterial pressure to maintain end-organ perfusion in presence of nonpulsatile flow remains unknown. Near infrared oxygenation monitoring during pLVAD support provides assessment of critical end-organ perfusion during VT, enabling successful mapping and ablation with the continual assurance of adequate brain oxygenation. This focused review provides practical use case scenarios for such an approach, which aims to allow mapping and ablation of ongoing VT while drastically reducing the risk of ischemic brain injury.

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.

Management of ventricular arrhythmias in heart failure: Current perspectives

Congestive heart failure (HF) is a progressive affliction defined as the inability of the heart to sufficiently maintain blood flow. Ventricular arrhythmias (VAs) are common in patients with HF, and conversely, advanced HF promotes the risk of VAs. Management of VA in HF requires a systematic, multimodality approach that comprises optimization of medical therapy and use of implantable cardioverter-defibrillator and/or device combined with cardiac resynchronization therapy. Catheter ablation is one of the most important strategies with the potential to abolish or decrease the number of recurrences of VA in this population. It can be a curative strategy in arrhythmia-induced cardiomyopathy and may even save lives in cases of an electrical storm. Additionally, modulation of the autonomic nervous system and stereotactic radiotherapy have been introduced as novel methods to control refractory VAs. In patients with end-stage HF and refractory VAs, an institution of the mechanical circulatory support device and cardiac transplant may be considered. This review aims to provide an overview of current evidence regarding management strategies of VAs in HF with an emphasis on interventional treatment.

Hyperkalemia in Patients With Left Ventricular Assist Devices

Background: Both hypo- and hyperkalemia are associated with adverse events in heart failure patients. Their effects on patients with left ventricular assist devices (LVADs) remains unknown.

Methods and Results: The cohort included consecutive patients undergoing LVAD implantation between 2014 and 2018. In all, 170 patients (median age 56 years; 117 males) were stratified according to serum potassium levels 1 month after implantation into 3 groups: hypokalemia (<3.5 mEq/L; n=15), normokalemia (n=146), and hyperkalemia (>5.0 mEq/L; n=9). Compared with the normokalemia group, the adjusted hazard ratios for 1-year mortality were 0.91 (95% confidence interval [CI] 0.21–3.92) for hypokalemia and 4.14 (95% CI 1.47–11.65) for hyperkalemia. In the hyperkalemia group, the prevalence of renin-angiotensin-aldosterone system inhibitors decreased and serum potassium levels normalized following the first month.

Conclusions: Hyperkalemia was associated with increased mortality during LVAD support. Management of serum potassium needs further investigation.

Clinical management of electrical storm: a current overview

The number of patients affected by electrical storm has been continuously increasing in emergency departments. Patients are often affected by multiple comorbidities requiring multidisciplinary interventions to achieve a clinical stability. Careful reprogramming of cardiac devices, correction of electrolyte imbalance, knowledge of underlying heart disease and antiarrhythmic drugs in the acute phase play a crucial role. The aim of this review is to provide a comprehensive overview of pharmacological treatment, latest transcatheter ablation techniques and advanced management of patients with electrical storm.

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.

Electrical Storm Ablation in a Patient in Cardiogenic Shock Supported by Impella 5.0

Intra-axial pumps are increasingly used to support cardiogenic shock. The occurrence of electrical storms in this setting is a rising issue, and data remain scarce about optimal management. We report the feasibility of ventricular tachycardia ablation in the presence of a recent surgically inserted Impella 5.0 device (Abiomed, Danvers, Massachusetts). (Level of Difficulty: Intermediate.)

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.

Mechanical circulatory support with Impella versus intra-aortic balloon pump or medical treatment in cardiogenic shock-a critical appraisal of current data

AIMS

Patients suffering from cardiogenic shock (CS) have a high mortality and morbidity. The Impella percutaneous left-ventricular assist device (LVAD) decreases LV preload, increases cardiac output, and improves coronary blood flow. We aimed to review and meta-analyze available data comparing Impella versus intra-aortic pump (IABP) counterpulsation or medical treatment in CS due to acute myocardial infarction or post-cardiac arrest.

METHODS AND RESULTS

Study-level data were analyzed. Heterogeneity was assessed using the I² statistic. Risk rates were calculated and obtained using a random-effects model (DerSimonian and Laird). Four studies were found suitable for the final analysis, including 588 patients. Primary endpoint was short-term mortality (in-hospital or 30-day mortality). In a meta-analysis of four studies comparing Impella versus control, Impella was not associated with improved short-term mortality (in-hospital or 30-day mortality; RR 0.84; 95% CI 0.57-1.24; p = 0.38; I² 55%). Stroke risk was not increased (RR 1.00; 95% CI 0.36-2.81; p = 1.00; I²2 0%), but risk for major bleeding (RR 3.11 95% CI 1.50-6.44; p = 0.002; I² 0%) and peripheral ischemia complications (RR 2.58; 95% CI 1.24-5.34; p = 0.01; I² 0%) were increased in the Impella group.

CONCLUSION

In patients suffering from severe CS due to AMI, the use of Impella is not associated with improved short-time survival but with higher complications rates compared to IABP and medical treatment. Better patient selection avoiding Impella implantation in futile situations or in possible lower risk CS might be necessary to elucidate possible advantages of Impella in future studies.