Ventricular Tachycardia in Ischemic Heart Disease

Outcomes of ventricular tachycardia ablation in patients with ischemic and non-ischemic cardiomyopathy: A propensity-score matched analysis

INTRODUCTION AND OBJECTIVES

Catheter ablation (CA) is effective in the treatment of ventricular tachycardia (VT). Although some observational data suggest patients with non-ischemic cardiomyopathy (NICM) have less favorable outcomes when compared to those with an ischemic etiology (ICM), direct comparisons are rarely reported. We aimed to compare the outcomes of VT ablation in a propensity-score matched population of ICM or NICM patients.

METHODS

Single-center retrospective study of consecutive patients undergoing VT ablation from 2012 to 2023. A propensity score (PS) was used to match ICM and NICM patients in a 1:1 fashion according to age, sex, left ventricular ejection fraction (LVEF), NYHA class, electrical storm (ES) at presentation, and previous endocardial ablation. The outcomes of interest were VT-free survival and all-cause mortality.

RESULTS

The PS yielded two groups of 71 patients each (mean age 63±10 years, 92% male, mean LVEF 35±10%, 36% with ES at presentation, and 23% with previous ablation), well matched for baseline characteristics. During a median follow-up of 2.3 (interquartile range IQR 1.3-3.8) years, patients with NICM had a significantly lower VT-free survival (53.5% vs. 69.0%, log-rank p=0.037), although there were no differences regarding all-cause mortality (22.5% vs. 16.9%, log-rank p=0.245). Multivariate analysis identified NICM (HR 2.34 [95% CI 1.32-4.14], p=0.004), NYHA class III/IV (HR 2.11 [95% CI 1.11-4.04], p=0.024), and chronic kidney disease (HR 2.23 [95% CI 1.25-3.96], p=0.006), as independent predictors of VT recurrence.

CONCLUSION

Non-ischemic cardiomyopathy patients were at increased risk of VT recurrence after ablation, although long-term mortality did not differ.

Catheter Ablation of Ventricular Tachycardia in Ischemic Heart Disease: What Is Known and New Perspectives

PURPOSE OF THE REVIEW

This review aims to evaluate current evidence regarding ventricular tachycardia ablation in patients with ischemic heart disease and explore novel approaches currently developing to improve procedural and long-term outcomes.

RECENT FINDINGS

Recently published trials (PARTITA, PAUSE-SCD, and SURVIVE-VT) have demonstrated the prognostic benefit of prophylactic ventricular tachycardia ablation compared to current clinical practice. Advanced cardiac imaging provides a valuable pre-procedural evaluation of the arrhythmogenic substrate, identifying ablation targets non-invasively. Advanced cardiac mapping techniques allow to better characterize arrhythmogenic substrate during ablation procedure. Emerging technologies like pulsed field ablation and ultra-low temperature cryoablation show promise in ventricular tachycardia ablation. Advancements in mapping techniques, ablation technologies, and pre-procedural cardiac imaging offer promise for improving ventricular tachycardia ablation outcomes in ischemic heart disease.

Clinical impact of stellate ganglion phototherapy on ventricular tachycardia storm requiring mechanical circulatory support devices: a case report

Background

Ventricular arrhythmias are a significant cause of morbidity and mortality in patients with ischaemic heart disease. When pharmacologic therapies, catheter ablation (CA), and implantable cardioverter defibrillator (ICD) are ineffective, stellate ganglion blockade (SGB), sympathectomy, and renal sympathetic denervation are considered. However, they are invasive for patients with high bleeding risk. We present a case of successfully recovering from haemodynamically unstable ventricular tachycardia (VT) storm with stellate ganglion phototherapy (SGP) in a non-invasive manner.

Case summary

A 73-year-old male presented to the emergency department with chief complaint of general malaise, resulting from VT storm associated with ischaemic cardiomyopathy. He had a history of CA and implantation of ICD. Despite multiple electrical cardioversions, pharmacologic therapies, and deep sedation with mechanical circulatory support (MCS), VT storm was not controlled. Thereafter, we irradiated the patient's neck with SGP to inhibit sympathetic neurological activity, which suppressed VT storm and dramatically improved his haemodynamic status.

Discussion

It has been reported that SGP is an alternative to SGB for refractory VT storm. Stellate ganglion phototherapy was easy and non-invasive to perform because we just irradiated the patient's neck with the near-infrared light for 5 min per day. If conventional therapies are ineffective in suppressing VT storm, SGP may be considered as a next step, especially for patients with high bleeding risk. However, since the effect of a single SGP lasts only 1-2 days, it should be performed as a bridge therapy to CA or sympathectomy. Stellate ganglion phototherapy may be effective in suppressing VT storm that requires MCS devices.

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

Background

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

Method

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

Results

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

Conclusion

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

Canine Model of Ischemia-Induced Ventricular Tachycardia

INTRODUCTION

Despite advances in antiarrhythmia therapies, ventricular tachycardia (VT) is a leading cause of sudden cardiac death. Investigation into the characteristics and new treatments for this arrhythmia is required to improve outcomes and a reproducible model of VT would be useful in these endeavors. We therefore created a canine model of ischemia-induced VT.

MATERIALS AND METHODS

A pacing lead was implanted in the right ventricle in canines (n = 13) and the left anterior descending artery was occluded in two locations for 2 h and subsequently released to create an ischemia-reperfusion injury. In the 10 dogs that survived the first 48 h following the initial study, a terminal study was conducted 4-7 d later and VT was induced using premature stimulation or burst pacing through the right ventricle lead. The arrhythmia was terminated using either antitachycardia pacing or a defibrillatory shock. Multiple inductions into sustained VT were attempted.

RESULTS

Sustained VT was induced in eight of 10 dogs with an average cycle length of 335 ± 70 bpm. Multiple episodes of VT were induced. Episodes of VT exhibited different electrocardiogram morphologies and cycle lengths in individual animals.

CONCLUSIONS

This canine model provides a consistent technique for inducing multiple episodes of sustained VT. It may be useful for investigating VT mechanisms and testing novel therapeutics and treatments for patients with VT.

Inter-American Society of Cardiology (CIFACAH-ELECTROSIAC) and Latin-American Heart Rhythm Society (LAHRS): multidisciplinary review on the appropriate use of implantable cardiodefibrillator in heart failure with reduced ejection fraction

BACKGROUND

Our main objective was to present a multidisciplinary review on the epidemiology of sudden cardiac death (SCD) and the tools that could be used to identify malignant ventricular arrhythmias (VAs) and to perform risk stratification. In addition, indications and contraindications for the use of implantable cardioverter defibrillator (ICD) in general and in special populations including the elderly and patients with chronic kidney disease (CKD) are also given.

METHODS

An expert group from the Inter American Society of Cardiology (IASC), through their HF Council (CIFACAH) and Electrocardiology Council (ElectroSIAC), together with the Latin American Heart Rhythm Society (LAHRS), reviewed and discussed the literature regarding the appropriate use of an ICD in people with heart failure (HF) with reduced ejection fraction (HFpEF). Indications and contraindications for the use of ICD are presented in this multidisciplinary review.

RESULTS

Numerous clinical studies have demonstrated the usefulness of ICD in both primary and secondary prevention of SCD in HFpEF. There are currently precise indications and contraindications for the use of these devices.

CONCLUSIONS

In some Latin American countries, a low rate of implantation is correlated with low incomes, but this is not the case for all Latin America. Determinants of the low rates of ICD implantation in many Latin American countries are still a matter of research. VA remains one of the most common causes of cardiovascular death associated with HFrEF and different tools are available for stratifying the risk of SCD in this population.

Strain Imaging and Ventricular Arrhythmia

Ventricular arrhythmia is one of the main causes of sudden cardiac death. Hence, identifying patients at risk of ventricular arrhythmias and sudden cardiac death is important but can be challenging. The indication for an implantable cardioverter defibrillator as a primary preventive strategy relies on the left ventricular ejection fraction as a measure of systolic function. However, ejection fraction is flawed by technical constraints and is an indirect measure of systolic function. There has, therefore, been an incentive to identify other markers to optimize the risk prediction of malignant arrhythmias to select proper candidates who could benefit from an implantable cardioverter defibrillator. Speckle-tracking echocardiography allows for a detailed assessment of cardiac mechanics, and strain imaging has repeatedly been shown to be a sensitive technique to identify systolic dysfunction unrecognized by ejection fraction. Several strain measures, including global longitudinal strain, regional strain, and mechanical dispersion, have consequently been proposed as potential markers of ventricular arrhythmias. In this review, we will provide an overview of the potential use of different strain measures in the context of ventricular arrhythmias.

The Association of Clustered Ventricular Arrhythmia and Cycle Length With Scar Burden in Cardiomyopathy

BACKGROUND

Patients with ≥2 ventricular arrhythmia (VA) events within 3 months (clustered VA) have increased risk for mortality.

OBJECTIVES

The aim of this study was to examine the association of risk factors including scar characteristics on cardiovascular magnetic resonance imaging with clustered VA and VA cycle length in nonischemic cardiomyopathy (NICM) and ischemic cardiomyopathy (ICM).

METHODS

Data from 329 primary prevention implantable cardioverter-defibrillator recipients (mean age 57 years, 26% women) were analyzed from the Left Ventricular Structural Predictors of Sudden Cardiac Death study.

RESULTS

Twenty-one patients developed clustered VA (median time 2.7 years after implantable cardioverter-defibrillator placement). Men had the greatest risk for recurrent VA. Patients with NICM and scar had the highest incidence rate of clustered VA. In patients with NICM, each 1-g increase in core scar correlated with greater clustered VA risk (HR: 1.19; 95% CI: 1.07-1.32). Gray scar was similar among subgroups. Patients with NICM with clustered VA had the longest mean VA cycle length (297 ± 40 milliseconds). Higher core scar burden correlated with longer VA cycle length in patients with NICM (P = 0.002), and higher body mass index correlated with shorter VA cycle length in those with ICM (P = 0.02). Type of VA was similar between cardiomyopathy subgroups, and no scar pattern predominated.

CONCLUSIONS

Clustered VA was most common in patients with NICM and scar, with greatest risk among those with larger core scar. Core scar correlated with slower VA in patients with NICM, and higher body mass index correlated with faster VA in those with ICM. Type of VA was similar by cardiomyopathy etiology, and no dominant scar pattern was associated with clustered VA.

The role of inflammation in the pathogenesis and treatment of arrhythmias

The pathogenesis of arrhythmias is complex and multifactorial. The role of inflammation in the pathogenesis of both atrial and ventricular arrhythmias (VA) has been explored. However, developing successful pharmacotherapy regimens based on those pathways has proven more of a challenge. This narrative review provides an overview of five common arrhythmias impacted by inflammation, including atrial fibrillation (AF), myocardial infarction, arrhythmogenic cardiomyopathy, cardiac sarcoidosis, and QT prolongation, and the potential role for anti-inflammatory therapy in their management. We identified arrhythmias and arrhythmogenic disease states with the most evidence linking pathogenesis to inflammation and conducted comprehensive searches of United States National Library of Medicine MEDLINE^® and PubMed databases. Although a variety of agents have been studied for the management of AF, primarily in an effort to reduce postoperative AF following cardiac surgery, no standard anti-inflammatory agents are used in clinical practice at this time. Although inflammation following myocardial infarction may contribute to the development of VA, there is no clear benefit with the use of anti-inflammatory agents at this time. Similarly, although inflammation is clearly linked to the development of arrhythmias in arrhythmogenic cardiomyopathy, data demonstrating a benefit with anti-inflammatory agents are limited. Cardiac sarcoidosis, an infiltrative disease eliciting an immune response, is primarily treated by immunosuppressive therapy and steroids, despite a lack of primary literature to support such regimens. In this case, anti-inflammatory agents are frequently used in clinical practice. The pathophysiology of arrhythmias is complex, and inflammation likely plays a role in both onset and duration, however, for most arrhythmias the role of pharmacotherapy targeting inflammation remains unclear.

Cardiac stereotactic ablative radiotherapy for refractory ventricular arrhythmias: A radical alternative? A narrative review of rationale and cardiological aspects

Ventricular arrhythmias are serious life-threatening cardiac disorders. Despite many technological improvements, a non-negligible number of patients present refractory ventricular tachycardias, resistant to a catheter ablation procedure, placing these patients in a therapeutic impasse. Recently, a cardiac stereotactic radioablative technique has been developed to treat patients with refractory ventricular arrhythmias, as a bail out strategy. This new therapeutic option historically brings together two fields of expertise unknown to each other, pointing out the necessity of an optimal partnership between cardiologists and radiation oncologists. As described in this narrative review, the understanding of cardiological aspects of the technique for radiation oncologists and treatment technical aspects comprehension for cardiologists represent a major challenge for the application and the future development of this promising treatment.

Flecainide in Ventricular Arrhythmias: From Old Myths to New Perspectives

Flecainide is an IC antiarrhythmic drug (AAD) that received in 1984 Food and Drug Administration approval for the treatment of sustained ventricular tachycardia (VT) and subsequently for rhythm control of atrial fibrillation (AF). Currently, flecainide is mainly employed for sinus rhythm maintenance in AF and the treatment of idiopathic ventricular arrhythmias (IVA) in absence of ischaemic and structural heart disease on the basis of CAST data. Recent studies enrolling patients with different structural heart diseases demonstrated good effectiveness and safety profile of flecainide. The purpose of this review is to assess current evidence for appropriate and safe use of flecainide, 30 years after CAST data, in the light of new diagnostic and therapeutic tools in the field of ischaemic and non-ischaemic heart disease.

Association between chronic obstructive pulmonary disease and ventricular arrhythmia: a nationwide population-based cohort study

The ventricular arrhythmia (VA)-chronic obstructive pulmonary disease (COPD) association and related risk factors remain unclear. Using 2001-2012 data from National Health Insurance Research Database, we retrospectively reviewed 71,838 patients diagnosed as having COPD and 71,838 age- and sex-matched controls. After adjustments for comorbidities, medication, urbanization level, and monthly income, patients with COPD had higher incidence rates of VA than did the controls (adjusted hazard ratio [aHR] [95% confidence interval (CI)]: 1.45 [1.25-1.68]). More hospitalization or emergency visits because of acute COPD exacerbation (aHRs [95% CIs] for first, second, and third visits: 1.28 [1.08-1.50], 1.75 [1.32-2.32], and 1.88 [1.46-2.41], respectively) and asthma-COPD overlap (aHR [95% CI]: 1.49 [1.25-1.79]) were associated with high VA risk in patients with COPD. In the multivariate analysis, heart failure (aHR [95% CI]: 2.37 [1.79-3.14]), diabetes (aHR [95% CI]:1.64 [1.29-2.08]), age ≥75 (aHR [95% CI]: 2.48 [1.68-3.67]), male (aHR [95% CI]: 1.69[1.34-2.12]), and class III antiarrhythmic drug use (aHR [95% CI]: 2.49 [1.88-3.28]) are the most significant risk factors of new onset of VA in patients with COPD.

Current challenges in sudden cardiac death prevention

Ischemic heart disease and non-ischemic dilated cardiomyopathy are the most common causes of arrhythmic sudden cardiac death (SCD). Implantable cardioverter defibrillator (ICD) therapy is the only strategy that proved to be effective in preventing SCD in high-risk individuals while the role of antiarrhythmic drugs is limited to symptoms relief. Current guidelines recommend selecting candidates to ICD implantation based on etiology, symptoms of heart failure (NYHA class), and severely depressed left ventricular ejection fraction, but these parameters are neither sensitive nor specific. The review addresses the mechanisms of SCD in patients with heart failure of either ischemic or non-ischemic etiology, risk stratification, and strategies for prevention of SCD in the clinical practice (including optimization of heart failure therapy, avoidance of triggering factors, antiarrhythmic drugs, ICD therapy, early resuscitation, and public access defibrillators).

Factors associated with recurrent postinfarction ventricular tachycardia following ablation

INTRODUCTION

Ablation of ventricular tachycardia is the main therapy for patients with drug-refractory ventricular tachycardia (VT). Although evidence suggests that VT ablation could lower the incidence of recurrent VT, many cases still develop VT in follow-up. In this study, we performed a systematic review and meta-analysis to examine risk factors for recurrent VT in patients with postinfarction VT who underwent VT ablation.

EVIDENCE ACQUISITION

We comprehensively searched the databases of MEDLINE and EMBASE from inception to March 2020. Included studies were cohort studies, experimental trials, or randomized controlled trials that evaluate the risk of recurrent VT in postinfarction VT patients who underwent VT ablation. Data from each study were combined using random-effects.

EVIDENCE SYNTHESIS

Thirteen studies involving 1803 postinfarction patients who underwent VT ablation were included. Inducibility after the procedure (pooled HR=1.71, P<0.001), lower baseline left ventricular ejection fraction (LVEF) (pooled HR=0.98, P<0.001) and higher baseline New York Heart Association (NYHA) classification (pooled HR=1.34, P=0.003) were significantly associated with VT recurrence during the follow-up. There was no significant association between age, gender or diabetes mellitus and VT recurrence.

CONCLUSIONS

Our meta-analysis demonstrated that inducibility after the procedure, lower baseline LVEF and higher baseline NYHA classification were associated with an increased risk of VT recurrence in postinfarction VT patients who underwent VT ablation.

Ventricular arrhythmias following continuous-flow left ventricular assist device implantation: A systematic review

Ventricular arrhythmias (VA) are not uncommon after continuous-flow left ventricular assist device (CF-LVAD) implantation. In this systematic review, we sought to identify the patterns of VA that occurred following CF-LVAD implantation and evaluate their outcomes. An electronic search was performed to identify all articles reporting the development of VA following CF-LVAD implantation. VA was defined as any episode of ventricular fibrillation (VF) or sustained (>30 seconds) ventricular tachycardia (VT). Eleven studies were pooled for the analysis that included 393 CF-LVAD patients with VA. The mean patient age was 57 years [95%CI: 54; 61] and 82% [95%CI: 73; 88] were male. Overall, 37% [95%CI: 19; 60] of patients experienced a new onset VA after CF-LVAD implantation, while 60% [95%CI: 51; 69] of patients had a prior history of VA. Overall, 88% of patients [95%CI: 78; 94] were supported on HeartMate II CF-LVAD, 6% [95%CI: 3; 14] on HeartWare HVAD, and 6% [95%CI: 2; 13] on other CF-LVADs. VA was symptomatic in 47% [95%CI: 28; 68] of patients and in 50% [95%CI: 37; 52], early VA (<30 days from CF-LVAD) was observed. The 30-day mortality rate was 7% [95%CI: 5; 11]. Mean follow-up was 22.9 months [95%CI: 4.8; 40.8], during which 27% [95%CI: 17; 39] of patients underwent heart transplantation. In conclusion, approximately a third of patients had new VA following CF-LVAD placement. VA in CF-LVAD patients is often symptomatic, necessitates treatment, and carries a worse prognosis.

A Retinoic Acid β2-Receptor Agonist Exerts Cardioprotective Effects

We previously discovered that oral treatment with AC261066, a synthetic selective agonist for the retinoic acid β₂-receptor, decreases oxidative stress in the liver, pancreas, and kidney of mice fed a high-fat diet (HFD). Since hyperlipidemic states are causally associated with myocardial ischemia and oxidative stress, we have now investigated the effects of AC261066 in an ex vivo ischemia/reperfusion (I/R) injury model in hearts of two prototypic dysmetabolic mice. We found that a 6-week oral treatment with AC261066 in both genetically hypercholesterolemic (ApoE^-/-) and obese (HFD-fed) wild-type mice exerts protective effects when their hearts are subsequently subjected to I/R ex vivo in the absence of added drug. In ApoE^-/- mice this cardioprotection ensued without hyperlipidemic changes. Cardioprotection consisted of attenuation of infarct size, diminution of norepinephrine (NE) spillover, and alleviation of reperfusion arrhythmias. This cardioprotection was associated with a reduction in oxidative stress and mast cell (MC) degranulation. We suggest that the reduction in myocardial injury and adrenergic activation, and the antiarrhythmic effects, result from decreased formation of oxygen radicals and toxic aldehydes known to elicit the release of MC-derived renin, promoting the activation of the local renin-angiotensin system leading to enhanced NE release and reperfusion arrhythmias. Because these beneficial effects of AC261066 occurred at the ex vivo level following oral drug treatment, our data suggest that AC261066 could be viewed as a therapeutic means to reduce I/R injury of the heart, and potentially also be considered in the treatment of other cardiovascular ailments such as chronic arrhythmias and cardiac failure.

Prophylactic catheter ablation of ventricular tachycardia in ischemic cardiomyopathy: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Catheter ablation is proven to be an effective strategy for drug refractory ventricular tachycardia (VT) in ischemic cardiomyopathy. However, the appropriate timing of VT ablation and identifying the group of patients that may receive the greatest benefit remains uncertain. There is limited data on the effect on prophylactic catheter ablation (PCA) in the prevention of implantable cardioverter defibrillator (ICD) therapy, electrical storm, and mortality.

METHODS

We performed a comprehensive literature search through November 1, 2017, for all eligible studies comparing PCA + ICD versus ICD only in eligible patients with ischemic cardiomyopathy. Clinical outcomes included all ICD therapies including ICD shocks and electrical storm. Additional outcomes included all-cause mortality, cardiovascular mortality, and complications.

RESULTS

Three randomized controlled trials (RCTs) (N = 346) met inclusion criteria. PCA was associated with a significantly lower ICD therapies (OR 0.49; CI 0.28 to 0.87; p = 0.01) including ICD shocks [OR 0.38; CI 0.22 to 0.64; p = 0.0003) and electrical storm (OR 0.55; CI 0.30 to 1.01; p = 0.05) when compared with ICD only. There was no significant difference in all-cause mortality (OR 0.77; CI 0.41 to 1.46; p = 0.42), cardiovascular mortality (OR 0.49; CI 0.16 to 1.50; p = 0.21), and major adverse events (OR 1.45; CI 0.52 to 4.01; p = 0.47) between two groups.

CONCLUSION

These results suggest prophylactic catheter ablation decreases ICD therapies, including shocks and electrical storm with no improvement in overall mortality. There is a need for future carefully designed randomized clinical trials.

Recent advances in the management of ventricular tachyarrhythmias

Ventricular arrhythmias are an important cause of cardiovascular morbidity and mortality, particularly in those with structural heart disease, inherited cardiomyopathies, and channelopathies. The goals of ventricular arrhythmia management include symptom relief, improving quality of life, reducing implantable cardioverter defibrillator shocks, preventing deterioration of left ventricular function, reducing risk of arrhythmic death, and potentially improving overall survival. Guideline-directed medical therapy and implantable cardioverter defibrillator implantation remain the mainstay of therapy to prevent sudden cardiac death in patients with ventricular arrhythmias in the setting of structural heart disease. Recent advances in imaging modalities and commercial availability of genetic testing panels have enhanced our mechanistic understanding of the disease processes and, along with significant progress in catheter-based ablative therapies, have enabled a tailored and more effective management of drug-refractory ventricular arrhythmias. Several gaps in our knowledge remain and require further research. In this article, we review the recent advances in the diagnosis and management of ventricular arrhythmias.