Antiarrhythmic Drugs or Catheter Ablation in the Management of Ventricular Tachyarrhythmias in Patients With Implantable Cardioverter-Defibrillators: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The effects of empagliflozin on ventricular arrhythmias in heart failure patients with an implantable cardioverter-defibrillator: a double-blind randomized controlled trial

Sodium-glucose transporter 2 (SGLT2) inhibitors such as empagliflozin are one of the main treatments for type 2 diabetes mellitus (DM2) and heart failure (HF). They have also demonstrated anti-arrhythmic effects in some preclinical and clinical studies. The purpose of this study was to assess the effects of empagliflozin on ventricular arrhythmias in HF patients with an implantable cardioverter-defibrillator (ICD). In a prospective double-blinded, randomized controlled trial of Iran County, Mashhad (72 patients 1:1), we compared the frequency and proportion of ventricular arrhythmias and ICD therapies during the 24 weeks to the prior 24 weeks. Results revealed that empagliflozin significantly reduced the frequency and proportion of ventricular tachycardia (VT)/fibrillation (VF) episodes (P = 0.019 and 0.039, respectively). Moreover, it tended to reduce the frequency and proportion of ICD therapies, including anti-tachycardia pacing (ATP) and shock. Subgroup analysis of patients with or without any antiarrhythmic drugs (digoxin, mexiletine, amiodarone, or sotalol) revealed that only patients who were previously on the antiarrhythmic drugs benefit from empagliflozin antiarrhythmic effects. In conclusion, empagliflozin exhibits anti-arrhythmic effects in HF patients with an ICD. Larger and long-term clinical studies are still needed to investigate and confirm all positive effects of SGLT2 inhibitors in this regard. Trial registration number: IRCT20120520009801N7 (Approval date: June 11, 2022).

Management of patients with an electrical storm or clustered ventricular arrhythmias: a clinical consensus statement of the European Heart Rhythm Association of the ESC-endorsed by the Asia-Pacific Heart Rhythm Society, Heart Rhythm Society, and Latin-American Heart Rhythm Society

Electrical storm (ES) is a state of electrical instability, manifesting as recurrent ventricular arrhythmias (VAs) over a short period of time (three or more episodes of sustained VA within 24 h, separated by at least 5 min, requiring termination by an intervention). The clinical presentation can vary, but ES is usually a cardiac emergency. Electrical storm mainly affects patients with structural or primary electrical heart disease, often with an implantable cardioverter-defibrillator (ICD). Management of ES requires a multi-faceted approach and the involvement of multi-disciplinary teams, but despite advanced treatment and often invasive procedures, it is associated with high morbidity and mortality. With an ageing population, longer survival of heart failure patients, and an increasing number of patients with ICD, the incidence of ES is expected to increase. This European Heart Rhythm Association clinical consensus statement focuses on pathophysiology, clinical presentation, diagnostic evaluation, and acute and long-term management of patients presenting with ES or clustered VA.

Bayesian analysis of the Substrate Ablation vs. Antiarrhythmic Drug Therapy for Symptomatic Ventricular Tachycardia trial

BACKGROUND AND AIMS

Bayesian analyses can provide additional insights into the results of clinical trials, aiding in the decision-making process. We analysed the Substrate Ablation vs. Antiarrhythmic Drug Therapy for Symptomatic Ventricular Tachycardia (SURVIVE-VT) trial using Bayesian survival models.

METHODS AND RESULTS

The SURVIVE-VT trial randomized patients with ischaemic cardiomyopathy and monomorphic ventricular tachycardia (VT) to catheter ablation or antiarrhythmic drugs (AAD) as a first-line strategy. The primary outcome was a composite of cardiovascular death, appropriate implantable cardioverter-defibrillator shocks, unplanned heart failure hospitalizations, or severe treatment-related complications. We used informative, skeptical, and non-informative priors with different probabilities of large effects to compute the posterior distributions using Markov Chain Monte Carlo methods. We calculated the probabilities of hazard ratios (HR) being <1, <0.9, and <0.75, as well as 2-year survival estimates. Of the 144 randomized patients, 71 underwent catheter ablation and 73 received AAD. Regardless of the prior, catheter ablation had a >98% probability of reducing the primary outcome (HR < 1) and a >96% probability of achieving a reduction of >10% (HR < 0.9). The probability of a >25% (HR < 0.75) reduction of treatment-related complications was >90%. Catheter ablation had a high probability (>93%) of reducing incessant/slow undetected VT/electric storm, unplanned hospitalizations for ventricular arrhythmias, and overall cardiovascular admissions > 25%, with absolute differences of 15.2%, 21.2%, and 20.2%, respectively.

CONCLUSION

In patients with ischaemic cardiomyopathy and VT, catheter ablation as a first-line therapy resulted in a high probability of reducing several clinical outcomes compared to AAD. Our study highlights the value of Bayesian analysis in clinical trials and its potential for guiding treatment decisions.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03734562.

Trigger and Substrate Mapping and Ablation for Ventricular Fibrillation in the Structurally Normal Heart

Sudden cardiac death (SCD) represents approximately 50% of all cardiovascular mortality in the United States. The majority of SCD occurs in individuals with structural heart disease; however, around 5% of individuals have no identifiable cause on autopsy. This proportion is even higher in those <40 years old, where SCD is particularly devastating. Ventricular fibrillation (VF) is often the terminal rhythm leading to SCD. Catheter ablation for VF has emerged as an effective tool to alter the natural history of this disease among high-risk individuals. Important advances have been made in the identification of several mechanisms involved in the initiation and maintenance of VF. Targeting the triggers of VF as well as the underlying substrate that perpetuates these lethal arrhythmias has the potential to eliminate further episodes. Although important gaps remain in our understanding of VF, catheter ablation has become an important option for individuals with refractory arrhythmias. This review outlines a contemporary approach to the mapping and ablation of VF in the structurally normal heart, specifically focusing on the following major conditions: idiopathic ventricular fibrillation, short-coupled ventricular fibrillation, and the J-wave syndromes-Brugada syndrome and early-repolarization syndrome.

Mexiletine for recurrent ventricular tachycardia in adult patients with structural heart disease and implantable cardioverter defibrillator: an EHRA systematic review

The aim of the study was to systematically review evidence on the effectiveness and safety of oral mexiletine administered in monotherapy or in combination with other antiarrhythmic drugs for recurrent ventricular arrhythmia (ventricular tachycardia/ventricular fibrillation, VT/VF) in adult patients with structural heart disease (SHD) and implantable cardioverter defibrillators (ICDs). We systematically searched MEDLINE, Embase, and CENTRAL databases from inception to 27 August 2021 for prospective and retrospective studies investigating mexiletine in the target population. The main outcome was the reduction of ICD therapy. The main safety outcome was the presence of any serious adverse events (SAEs) leading to mexiletine discontinuation. Study quality was assessed using the Cochrane risk of bias tool or the Newcastle–Ottawa scale. Four studies comprising 86 mexiletine recipients were included in the review. We also obtained individual data of 50 patients from two studies. Ischaemic cardiomyopathy (ICM) was present in 86% of patients. The quality of included studies was moderate/low. A narrative review was undertaken as studies varied widely in terms of study population and treatment. Across studies, mexiletine treatment (with or without amiodarone) seemed to consistently reduce the number of ICD therapies especially in a population where catheter ablation (CA) was unsuccessful or contraindicated. In ICM patients deemed eligible for CA, mexiletine seemed to be inferior to CA. Mexiletine was discontinued in 14% of cases, mainly for gastrointestinal or neurological SAE. Mexiletine seems to be an option for the long-term treatment of recurrent VT/VF in adult patients with SHD, especially ICM, and ICD in whom CA was unsuccessful or not suitable.

Substrate Ablation vs Antiarrhythmic Drug Therapy for Symptomatic Ventricular Tachycardia

BACKGROUND

In patients with ischemic cardiomyopathy and an implantable cardioverter-defibrillator (ICD), catheter ablation and antiarrhythmic drugs (AADs) reduce ICD shocks, but the most effective approach remains uncertain.

OBJECTIVES

This trial compares the efficacy and safety of catheter ablation vs AAD as first-line therapy in ICD patients with symptomatic ventricular tachycardias (VTs).

METHODS

The SURVIVE-VT (Substrate Ablation vs Antiarrhythmic Drug Therapy for Symptomatic Ventricular Tachycardia) is a prospective, multicenter, randomized trial including patients with ischemic cardiomyopathy and appropriated ICD shock. Patients were 1:1 randomized to complete endocardial substrate-based catheter ablation or antiarrhythmic therapy (amiodarone + beta-blockers, amiodarone alone, or sotalol ± beta-blockers). The primary outcome was a composite of cardiovascular death, appropriate ICD shock, unplanned hospitalization for worsening heart failure, or severe treatment-related complications.

RESULTS

In this trial, 144 patients (median age, 70 years; 96% male) were randomized to catheter ablation (71 patients) or AAD (73 patients). After 24 months, the primary outcome occurred in 28.2% of patients in the ablation group and 46.6% of those in the AAD group (hazard ratio [HR]: 0.52; 95% CI: 0.30-0.90; P = 0.021). This difference was driven by a significant reduction in severe treatment-related complications (9.9% vs 28.8%, HR: 0.30; 95% CI: 0.13-0.71; P = 0.006). Eight patients were hospitalized for heart failure in the ablation group and 13 in the AAD group (HR: 0.56; 95% CI: 0.23-1.35; P = 0.198). There was no difference in cardiac mortality (HR: 0.93; 95% CI: 0.19-4.61; P = 0.929).

CONCLUSIONS

In ICD patients with ischemic cardiomyopathy and symptomatic VT, catheter ablation reduced the composite endpoint of cardiovascular death, appropriate ICD shock, hospitalization due to heart failure, or severe treatment-related complications compared to AAD. (Substrate Ablation vs Antiarrhythmic Drug Therapy for Symptomatic Ventricular Tachycardia [SURVIVE-VT]: NCT03734562).

A novel optimized adaptive servo-ventilation setting for a patient with severe heart failure based on the echocardiogram: a case report

Background

Adaptive servo-ventilation (ASV) is a non-invasive positive-pressure ventilation therapy considered beneficial for treating heart failure (HF) in patients with central sleep apnoea. However, to the best of our knowledge, there is no evidence indicating that this therapy increases the mortality in HF patients. We hypothesized that ASV settings are important for HF patients with reduced ejection fraction. Therefore, to determine the suitable ASV setting for such patients, we optimized these settings to improve the left ventricular (LV) output during the therapy.

Case summary

We present a case of HF caused by dilated cardiomyopathy in a 45-year-old man. He was hospitalized due to HF; his LV ejection fraction was ∼20%, and haemodynamics analysis revealed his HF grade was Forrester subset IV. During hospitalization, he was diagnosed with sleep apnoea; therefore, we induced ASV with our optimized setting using an echocardiogram evaluating stroke volume (SV). Using this method, we could determine the appropriate setting that increased his SV and improved his apnoea–hypopnoea index. At the 5th-year follow-up, he had no dyspnoea on effort (New York Heart Association Functional Classification I). He continued using the ASV with good adherence, and no hospitalization for ventricular arrhythmia and HF was reported.

Discussion

Our ASV optimized setting showed beneficial effects in an HF patient with reduced ejection fraction. This method improved the patient’s SV and apnoea–hypopnoea index, indicating that this novel method should be considered for HF patients with reduced ejection fraction.

Recent insights into mechanisms and clinical approaches to electrical storm

Electrical storm, characterized by repetitive ventricular tachycardia/fibrillation (VT/VF) over a short period, is becoming commoner with widespread use of implantable cardioverter-defibrillator (ICD) therapy. Electrical storm, sometimes called "arrhythmic storm" or "VT-storm", is usually a medical emergency requiring hospitalization and expert management, and significantly affects short- and long-term outcomes. This syndrome typically occurs in patients with underlying structural heart disease (ischemic or non-ischemic cardiomyopathy) or inherited channelopathies. Triggers for electrical storm should be sought but are often unidentifiable. Initial management is dictated by the hemodynamic status, while subsequent management typically involves ICD interrogation and reprogramming to reduce recurrent shocks, identification/management of triggers like electrolyte abnormalities, myocardial ischemia, or decompensated heart failure, and antiarrhythmic-drug therapy or catheter ablation. Sympathetic nervous system activation is central to the initiation and maintenance of arrhythmic storm, so autonomic modulation is a cornerstone of management. Sympathetic inhibition can be achieved with medications (particularly beta-adrenoreceptor blockers), deep sedation, or cardiac sympathetic denervation. More definitive management targets the underlying ventricular arrhythmia substrate to terminate and prevent recurrent arrhythmia. Arrhythmia targeting can be achieved with antiarrhythmic medications, catheter ablation or more novel therapies such as stereotactic radiation therapy that targets the arrhythmic substrate. Mechanistic studies point to adrenergic activation and other direct consequences of ICD-shocks in promoting further arrhythmogenesis and hypocontractility. Here, we review the pathophysiologic mechanisms, clinical features, prognosis, and therapeutic options for electrical storm. We also outline a clinical approach to this challenging and complex condition, along with its mechanistic basis.

Gender differences in patients with structural heart disease undergoing VT ablation

INTRODUCTION

This study sought to examine gender differences in patients with structural heart disease (SHD) referred for ablation of ventricular tachycardia (VT).

BACKGROUND

Female patients are often underrepresented in large studies. Significant differences in the clinical presentation, treatment, and prognosis of female patients have been described in previous studies.

METHODS AND RESULTS

We investigated 88 female patients with SHD undergoing VT ablation (mean age 59 years, 56% nonischemic cardiomyopathy, mean left ventricular ejection fraction 35%, 82% in electrical storm). A case-control study with 88 male patients was performed and the results regarding clinical and procedural characteristics, acute and long-term results of the two groups were compared. The female patients had more arrhythmogenic substrate, as they more commonly presented with electrical storm (p = .016) and had a higher number of inducible VT morphologies during the procedure (p = .018). Moreover, the female patients were less likely to have an optimized heart failure medical treatment at baseline (p = .030) and required more time from the first manifestation of the VT to ablation referral (p = .034). Although fewer epicardial ablations were performed in female patients (p = .019), the two groups showed similar results regarding VT noninducibility as ablation endpoint (p = .844), major procedure-related complications (p = .719) and freedom from VT during follow-up (p = .268). Moreover, the overall mortality in the two groups was similar (p = .176). Advanced NYHA class was associated with worse transplant and assist-device-free survival in the female group.

CONCLUSION

Female patients presenting for VT ablation had more arrhythmogenic substrate and were less likely to have an optimized heart failure medical treatment. Nevertheless, the procedural acute and long-term outcomes between the two genders were similar.

Implantable cardioverter defibrillator shocks from ventricular tachyarrhythmias in patients with ischemic heart disease: Preventative measures, shortcomings, cost-effectiveness, and global practice perspectives

Implantable cardioverter defibrillators (ICDs) have proven to be life-saving devices in patients with ischemic cardiomyopathy (ICM) who are prone to develop ventricular tachycardia (VT) and fibrillation (VF). Antiarrhythmic drugs (AADs) are commonly prescribed in many such patients with ICDs to treat and prevent different forms of arrhythmias in clinical practice. When these patients experience recurrent monomorphic VT despite chronic AADs therapy, or when AAD therapy is contraindicated or not tolerated, and VT storm is refractory to AAD therapy, catheter ablation constitute guideline-based class I indication of treatment. However, what should be the most appropriate strategy to prevent first ICD shock or subsequent multiple shocks from VT/VF in patients with ICM who undergo ICD implantation without prior incidence of cardiac arrest, remains debatable. The purpose of this review is to discuss preventative aspects of ICD shocks for VT and the shortcomings of these measures along with the cost-effectiveness and global perspectives based on the current knowledge of the topic.

Meta-analysis of catheter ablation in patients with post-infarct cardiomyopathy undergoing defibrillator implantation

BACKGROUND

Patients with post-infarct cardiomyopathy and ventricular arrhythmias (VT) necessitating implantable cardioverter defibrillators (ICD) are at risk of recurrent shocks with increased morbidity.

METHODS

A comprehensive search of electronic databases for all randomized clinical trials that evaluated the role of catheter ablation as a preventive strategy at the time of secondary prevention ICD implantation was performed. We calculated hazard ratios (HR) and 95% confidence intervals (CI) using random-effects model.

RESULTS

Four trials were identified with a total of 505 patients (average age 66.4 ± 9.0 years; 87.7% were male). Preventive ablation was associated with a significant reduction in appropriate device therapies (shocks and/or anti-tachycardia therapy) (HR = 0.62; 95% CI = 0.46-0.82; P < .01), sustained VT (HR = 0.74; 95% CI = 0.55-0.99; P = .04) compared to control. There were no differences in inappropriate device shocks (HR = 0.80; 95% CI = 0.38-1.71), all-cause death (HR = 0.93; 95% CI = 0.53-1.64), cardiac death (HR = 0.63; 95% CI = 0.29-1.36), arrhythmic death (HR = 0.26; 95% CI = 0.05-1.31), or cardiac hospitalization (HR = 0.79; 95% CI = 0.57-1.11) between strategies. Preventive ablation was associated with improved SF-36 physical component (mean difference = 2.81; 95% CI-0.53-5.10; P = .02), but not the mental component (mean difference = 1.30; 95% CI = -2.06-4.66).

CONCLUSION

Among patients with post-infarct cardiomyopathy and VT, preventive catheter ablation at the time of ICD implantation is associated with a significant reduction of appropriate ICD therapy and sustained VT, and improvement in the physical component of quality-of-life, but no reduction in mortality.

Secondary prevention of sudden cardiac death

The prevention and treatment of sudden cardiac death (SCD) remains a significant public health challenge. For patients with a history of sudden death attributable to ventricular arrhythmia, implantable cardioverter-defibrillator (ICD) therapy is a mainstay of treatment, although these patients remain at high risk for recurrent ventricular arrhythmia and defibrillator therapies. In this review, we summarize landmark clinical trials evaluating the efficacy of ICD therapy in secondary prevention patients, review clinical outcomes including mode of death in survivors of SCD, and highlight the role for systematic diagnostic evaluation. We additionally discuss the invasive electrophysiological management of these patients, including ICD selection and programming as well as the role and timing of antiarrhythmic drug therapy and catheter ablation. Finally, we frame future challenges and needs to advance the care for secondary prevention patients.