Ventricular Tachycardia and ICD Therapy Burden With Catheter Ablation Versus Escalated Antiarrhythmic Drug Therapy

Catheter ablation versus medical therapy for ventricular tachycardia in patients with ischemic heart disease: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Ventricular tachycardia (VT) is a common chronic complication of ischemic heart disease (IHD), even in the era of contemporary coronary intervention. The use of implantable cardioverter-defibrillators (ICDs) has reduced mortality, but ICD shocks can be painful and traumatizing. Catheter ablation has been posited to reduce VT incidence and is commonly used in IHD patients when antiarrhythmic drugs do not suppress VT.

PURPOSE

We aim to review the clinical efficacy and safety of catheter ablation vs medical therapy in patients with IHD.

METHODS

We conducted comprehensive searches across PubMed, CENTRAL, Web of Science, Scopus, and Embase until May 2024. Pooled data were reported using risk ratio (RR) for dichotomous outcomes and mean difference (MD) for continuous outcomes. This systematic review and meta-analysis was registered with PROSPERO ID: CRD42024551760.

RESULTS

We included eight RCTs with a total of 1252 patients. Patients who underwent catheter ablation had a lower risk of VT storms compared to those who received medical therapy alone [RR: 0.74 with 95 % CI: (0.60, 0.91), P = 0.005), Compared to medical therapy, the catheter ablation group also required less appropriate ICD therapy [RR: 0.72 with 95 % CI: (0.57, 0.90), P = 0.005), and fewer appropriate ICD shocks [RR: 0.75 with 95 % CI: (0.57, 0.99), P = 0.04). However, there was no significant difference in Ventricular tachycardia/Ventricular fibrillation (VT/VF) recurrence [RR: 0.94 with 95 % CI: (0.83, 1.06), P = 0.33) and all-cause mortality [RR: 0.87 with 95 % CI: (0.70, 1.09), P = 0.22).

CONCLUSION

Catheter ablation is associated with a significant reduction in ventricular storms, appropriate ICD therapy, and appropriate ICD shocks while demonstrating similar safety in managing VT in IHD patients compared to medical therapy alone.

Incidence and Predictors of Appropriate Implantable Cardioverter Defibrillator Therapy in Japanese Ischemic Heart Disease Patients

BACKGROUND

Although the efficacy of an implantable cardioverter defibrillator (ICD) in preventing sudden cardiac death is well established, the incidence and predictors of appropriate ICD therapy in Japanese ischemic heart disease (IHD) patients remain unclear.

METHODS AND RESULTS

We retrospectively studied Japanese 141 IHD patients undergoing transvenous ICD or cardiac resynchronization therapy with a defibrillator (CRT-D) implantation for primary or secondary prevention at Hirosaki University Hospital. Over a mean (±SD) follow-up period of 5.5±2.8 years, the incidence of appropriate ICD therapy was similar in the primary and secondary prevention groups, although it was relatively more frequent in the first 2 years in the secondary prevention group. Four patients died due to sustained ventricular tachycardia (VT) or ventricular fibrillation (VF), mainly due to post-shock pulseless electrical activity. Once patients had received their first appropriate ICD therapy, 49.2% received second appropriate ICD therapy within 6 months. Cox proportional hazard analysis revealed that sustained VT as an index life-threatening ventricular tachyarrhythmia before ICD/CRT-D implantation was an independent predictor of appropriate ICD therapy, but VF was not.

CONCLUSIONS

The incidence of appropriate ICD therapy was comparable in primary and secondary prevention among Japanese IHD patients. We need to recognize the high-risk period for second appropriate ICD therapy after the first therapy and sustained VT as index life-threatening ventricular tachyarrhythmia as a risk factor for appropriate ICD therapy.

Stereotactic arrhythmia radioablation for ventricular tachycardia: a review of clinical trials and emerging roles of imaging

Ventricular tachycardia (VT) is a severe arrhythmia commonly treated with implantable cardioverter defibrillators, antiarrhythmic drugs and catheter ablation (CA). Although CA is effective in reducing recurrent VT, its impact on survival remains uncertain, especially in patients with extensive scarring. Stereotactic arrhythmia radioablation (STAR) has emerged as a novel treatment for VT in patients unresponsive to CA, leveraging techniques from stereotactic body radiation therapy used in cancer treatments. Recent clinical trials and case series have demonstrated the short-term efficacy and safety of STAR, although long-term outcomes remain unclear. Imaging techniques, such as electroanatomical mapping, contrast-enhanced magnetic resonance imaging and nuclear imaging, play a crucial role in treatment planning by identifying VT substrates and guiding target delineation. However, challenges persist owing to the complex anatomy and variability in target volume definitions. Advances in imaging and artificial intelligence are expected to improve the precision and efficacy of STAR. The exact mechanisms underlying the antiarrhythmic effects of STAR, including potential fibrosis and improvement in cardiac conduction, are still being explored. Despite its potential, STAR should be cautiously applied in prospective clinical trials, with a focus on optimizing dose delivery and understanding long-term outcomes. Collaborative efforts are necessary to standardize treatment strategies and enhance the quality of life for patients with refractory VT.

Ten-Year Outcomes and Predictors of Mortality Following Catheter Ablation of Ventricular Tachycardia

BACKGROUND

Catheter ablation is the primary treatment option for idiopathic ventricular tachycardia (VT). It plays a key role in acute therapy of electrical storm, treatment of VTs in patients with structural heart disease (SHD), and can reduce VT burden. Here we report on 10-year clinical outcomes following VT ablation from patients enrolled in the prospective German Ablation Registry.

METHODS AND RESULTS

Long-term follow-up was conducted on 334 patients undergoing VT ablation (118/334, 35%) with structurally normal hearts and 216 out of 334 (65%) with SHD, including 161 out of 216 (75%) with ischemic heart disease at 38 centers. Follow-up was completed in 94.8% of patients. Median observation time was 10.8 (4.3-12.3) years, with a 10-year all-cause mortality rate of 39.4%. VT ablation in patients with SHD was associated with worse outcome when compared with patients with structurally normal hearts (estimated 10-year mortality for SHD 54.8% versus structurally normal hearts 12.1%). Estimated 10-year mortality following VT ablation was highest in patients with ischemic heart disease (62.4%). Significant predictors of mortality following VT ablation included age (hazard ratio [HR], 2.35 [1.90-2.92] per decade), left ventricular ejection fraction ≤30% (HR, 2.11 [1.44-3.10]), diabetes (HR, 1.73 [1.14-2.61]), incessant VT (HR, 2.96 [1.74-5.03]), linear lesion (HR, 1.46 [0.99-2.16]), and acute procedural failure (HR, 2.57 [1.39-4.77]). Procedural failure was the only statistically significant predictor for VT recurrence during follow-up (HR, 3.76 [1.59-8.91]).

CONCLUSIONS

Within an all-comer patient cohort, estimated 10-year all-cause mortality following VT ablation is 39.4%. Mortality after VT ablation is worse in patients with SHD and highest for patients with ischemic heart disease. Acute procedural success plays a major role in predicting VT recurrence and long-term mortality.

Contemporary Management and Prognostic Factors of Arrhythmia Recurrence in Patients with High-Energy Discharge of Cardiac Implantable Electronic Devices

Background and Objectives: Understanding the underlying causes of implantable cardioverter-defibrillator (ICD) discharges is vital for effective management. This study aimed to evaluate the characteristics of patients admitted following ICD discharge, focusing on myocardial ischemia as a potential exacerbating factor and potential risk factors for VT recurrence. Materials and Methods: This retrospective, single-center study included 81 patients with high energy discharge from cardiac implantable electronic device admitted urgently to the cardiology department from 2015 to 2022. The exclusion criterion was ST-segment elevation acute coronary syndrome. Data were collected anonymously from electronic medical records. Patients were categorized based on coronary angiography, percutaneous angioplasty, presence of significant stenosis, recurrent ventricular tachycardia (VT), and catheter ablation. Clinical variables, including demographic data, echocardiographic parameters, and pharmacotherapy, were analyzed. The primary endpoint was the recurrence of VT during in-hospital stay. Results: Among 81 patients, predominantly male (86.4%), with a mean age of 63.6 years, 55 (67.9%) had coronary artery disease (CAD) as the primary etiology for ICD implantation. Coronary angiography was performed in 34 patients (42.0%) and showed significant stenosis (>50%) in 18 (41.8%) patients, while 8 (26.0%) individuals underwent percutaneous coronary intervention (PCI). Recurrent VT occurred in 21 subjects (26.3%), while ventricular catheter ablation was performed in 36 patients (44.0%). Referral for urgent coronary angiography was associated with presence of diabetes (p = 0.028) and hyperlipidemia (p = 0.022). Logistic regression analysis confirmed NYHA symptomatic class (OR 4.63, p = 0.04) and LVH (OR 10.59, p = 0.049) were independently associated with relapse of VT. CAD patients underwent catheter ablation more frequently (p = 0.001) than those with dilated cardiomyopathy. Conclusions: The study showed a low referral rate for coronary angiography among patients with ICD discharge. Presence of LVH and preexisting symptomatic class influence arrhythmia recurrence. Understanding these associations can guide personalized management strategies for ICD recipients.

A Comprehensive Review on the Electrocardiographic Manifestations of Cardiac Sarcoidosis: Patterns and Prognosis

PURPOSE OF REVIEW

Cardiac sarcoidosis (CS) refers to cardiac involvement in sarcoidosis and is usually associated with worse outcomes. This comprehensive review aims to elucidate the electrocardiographic (ECG) signs and features associated with CS, as well as examine modern techniques and their importance in CS evaluation.

RECENT FINDINGS

The exact pathogenesis of CS is still unclear, but it stems from an abnormal immunological response triggered by environmental factors in individuals with genetic predisposition. CS presents with non-cardiac symptoms; however, conduction system abnormalities are common in patients with CS. The most common electrocardiographic (ECG) signs include atrioventricular blocks and ventricular tachyarrhythmia. Distinct patterns, such as fragmented QRS complexes, T-wave alternans, and bundle branch blocks, are critical indicators of myocardial involvement. The application of advanced ECG techniques such as signal-averaged ECG, Holter monitoring, wavelet-transformed ECG, microvolt T-wave alternans, and artificial intelligence-supported analysis holds promising outcomes for opportune detection and monitoring of CS. Timely utilisation of inexpensive and readily available ECG possesses the potential to allow early detection and intervention for CS. The integration of artificial intelligence models into ECG analysis is a promising approach for improving the ECG diagnostic accuracy and further risk stratification of patients with CS.

Optimizing ventricular tachycardia ablation through imaging-based assessment of arrhythmic substrate: A comprehensive review and roadmap for the future

Ventricular tachycardia (VT) is a life-threatening heart rhythm and has long posed a complex challenge in the field of cardiology. Recent developments in advanced imaging modalities have aimed to improve comprehension of underlying arrhythmic substrate for VT. To this extent, high-resolution cardiac magnetic resonance (CMR) and cardiac computed tomography (CCT) have emerged as tools for accurately visualizing and characterizing scar tissue, fibrosis, and other critical structural abnormalities within the heart, providing novel insights into VT triggers and substrate. However, clinical implementation of knowledge derived from these advanced imaging techniques in improving VT treatment and guiding invasive therapeutic strategies continues to pose significant challenges. A pivotal concern lies in the absence of standardized imaging protocols and analysis methodologies, resulting in a large variance in data quality and consistency. Furthermore, the clinical significance and outcomes associated with VT substrate characterization through CMR and CCT remain dynamic and subject to ongoing evolution. This highlights the need for refinement of these techniques before their reliable integration into routine patient care can be realized. The primary objectives of this study are twofold: firstly, to provide a comprehensive overview of the studies conducted over the last 15 years, summarizing the current available literature on imaging-based assessment of VT substrate. Secondly, to critically analyze and evaluate the selected studies, with the aim of providing valuable insights that can inform current clinical practice and future research.

A Systematic Review and Meta-Analysis of Catheter Ablation Versus Anti-arrhythmic Drugs for Treatment of Ventricular Arrhythmia

Catheter ablation (CA) and anti-arrhythmic drugs (AADs) minimize implanted cardioverter-defibrillator (ICD) shocks in individuals with ischemic cardiomyopathy and an ICD, while the best strategy is still unknown. CA has been proposed as a potentially effective means of reducing the occurrence of ICD events in a number of studies; however, there were insufficient relevant dates from randomized controlled trials. A meta-analysis and systematic review of randomized controlled trials were carried out to evaluate the efficacy of CA for the prevention of VA in patients with ischemic heart disease. Cardiovascular mortality, an unscheduled hospitalization due to increasing heart failure, appropriate ICD shock, or serious treatment-related consequences comprised the composite primary outcome. AADs were examined in six trials (n = 1564; follow-up = 15 ± 8 months), while CA was evaluated in four trials (n = 682; follow-up = 12 ± 6 months). Both CA (odds ratio (OR) 0.65, 95% confidence interval (CI) 0.47-0.82, p = 0.001) and AADs (OR 0.76, 95% CI 0.32-0.84, p = 0.034) significantly reduced the number of suitable ICD interventions, with no discernible difference between the two treatment approaches. AADs were observed to reduce incorrect ICD interventions (OR 0.38, p = 0.001), but CA did not. During follow-up, there was no correlation seen between reduced mortality and either CA or AAD. When compared to AAD, CA decreased the composite endpoint of cardiovascular death, adequate ICD shock, heart failure-related hospitalization, or severe treatment-related consequences in ICD patients with ischemic cardiomyopathy and symptomatic VT.