Prognostic importance of defibrillator shocks in patients with heart failure

Lead Management: Device Programming and Defibrillation Threshold Testing

Implantable cardioverter-defibrillators (ICDs) reduce sudden cardiac death (SCD) and improve survival in patients with a history of life-threatening arrhythmia or sudden cardiac arrest, and in select populations at high risk of SCD due to ventricular arrhythmias. However, patients with ICDs may receive inappropriate or unnecessary shocks, which have been associated with pro-arrhythmia, psychological sequelae, poor quality of life, and increased mortality. The benefits and risks of ICD therapy are therefore directly impacted on by physician operative and programming decisions. This article aims to provide a detailed review of transvenous ICD programming as guided by clinical trials.

Stellate ganglion block therapy in management of ventricular electrical storm: A case report

Sympathetic overactivity is a recognized underlying mechanism contributing to the pathogenesis of ventricular electrical storm (VES). The growing body of evidence supports the efficacy of stellate ganglion block (SGB) in attenuating myocardial sympathetic tone, rendering it a valuable adjunctive therapy for managing VES. This case report presents the clinical details of a 60-year-old patient admitted for ventricular tachycardia (VT), necessitating the implantation of an implantable cardioverter defibrillator (ICD) to mitigate the risk of fatal ventricular arrhythmias (VAs). Subsequently, the patient received repeated antitachycardia pacing (ATP) therapy due to persistent symptomatic VT episodes. SGB was contemplated due to the patient's hemodynamic instability during episodes of VT and the ineffectiveness of pharmacotherapy. Initially, complete suppression of VT was achieved for 3 days using local anesthesia, followed by partial suppression via pulsed radiofrequency (PRF), culminating in sustained relief for 3 months following continuous radiofrequency (CRF) therapy. Different methods of SGB elicited varied responses in this patient. CRF appeared to be more effective than PRF and conventional local anesthetics. CRF ablation of the stellate ganglion for refractory VAs offers a potential therapeutic option.

Comparison of Oral Procainamide and Mexiletine Treatment of Recurrent and Refractory Ventricular Tachyarrhythmias

Background: Antiarrhythmic therapy for recurrent ventricular arrhythmias (VAs) in patients having undergone catheter ablation and in whom amiodarone and/or beta-blockers were ineffective or contraindicated is a controversial issue. Purpose: The present study sought to compare the efficacy and tolerability of oral procainamide and mexiletine in patients with recurrent ventricular arrhythmias when the standard therapy strategy failed. Methods: All patients with an implantable cardioverter defibrillator (ICD) treated with oral procainamide or mexiletine for recurrent ventricular tachycardia (VT) or ventricular fibrillation (VF) in two cardiology divisions between January 2010 and January 2020 were enrolled. Patients were divided into group A (oral procainamide) and group B (mexiletine) and the two groups were compared to each other. The primary endpoint was the efficacy of therapy; the secondary endpoint was the discontinuation of therapy. All events that occurred during procainamide or mexiletine treatment were compared with a matched duration period before the initiation of the therapy. Antiarrhythmic therapy was considered effective when a ≥80% reduction of the sustained ventricular arrhythmias burden recorded by the ICD was achieved. Results: A total of 68 consecutive patients (61 males, 89.7%; mean age 74 ± 10 years) were included in this retrospective analysis. After a median follow-up of 19 months, 38 (56%) patients had a significant reduction in the VA burden. After multivariable adjustment, therapy with procainamide was independently associated with an almost 3-fold higher efficacy on VA suppression compared to mexiletine (HR 2.54, 95% CI 1.06-6.14, p = 0.03). Only three patients (9%) treated with procainamide presented severe side effects (dyspnea or hypotension) requiring discontinuation of therapy compared with six patients (18%) treated with mexiletine who interrupted therapy because of severe side effects (p = 0.47). Conclusions: Compared to mexiletine, oral procainamide had a higher efficacy for the treatment of recurrent and refractory VAs, and showed a good profile of tolerability.

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.

Elevated B-Type Natriuretic Peptide Level as a Residual Risk Factor for Ventricular Arrhythmias Among Patients Undergoing Cardiac Resynchronization Therapy With Improved Left Ventricular Ejection Fraction

Background

Patients who achieve improved left ventricular ejection fraction (LVEF >35%) with cardiac resynchronization therapy (CRT) are at a lower risk of ventricular arrhythmia (VA). Little is known about the significance of the B-type natriuretic peptide (BNP) level for the risk of VA. This study investigated the risk factors for VA in CRT and the risk stratification of VA with BNP in CRT with improved LVEF.

Methods and Results

This study evaluated 352 CRT patients from 2012 to 2020. Patients were categorized into 2 groups: improved LVEF (impEF; LVEF >35%), and low LVEF (lowEF; LVEF ≤35%). The serum BNP levels 6 months after CRT device implantation were measured. The primary endpoint was defined as VA requiring treatment with anti-tachycardia pacing or shock or persisting for ≥30 s. Overall, 102 patients had improved LVEF. The impEF group had a significantly lower VA risk than the lowEF group. Patients with low BNP had a lower VA risk than those with high BNP; however, no significant difference was observed between patients with high BNP and those in the lowEF group. Univariate analysis revealed that high BNP was a predictor of VA in the impEF group.

Conclusions

The VA risk is reduced with improved LVEF after CRT but not with high BNP levels. The post-BNP level after CRT implantation is a useful marker for predicting VA in patients with improved LVEF.

Synthesized V7 QRS Amplitude and Oversensing Episodes in Patients With Subcutaneous Implantable Cardioverter-Defibrillators

BACKGROUND

Patients with subcutaneous implantable cardioverter-defibrillators (S-ICDs) experience an oversensing episode (OS) more frequently than those with transvenous ICDs. However, no established electrocardiography (ECG) parameters can accurately detect an OS. This study aimed to evaluate the incidence of an OS in real-world clinical practice and the association of synthesized 18-lead ECG (syn18-ECG) parameters with an OS.

METHODS

We retrospectively included 21 consecutive patients who underwent S-ICD implantation and collected syn18-ECG parameters. We placed the generator in a deep posterior position and defined an OS as an inappropriate charging episode caused by cardiac or noncardiac signals. A SMART pass filter and two tachyarrhythmia zones were programed.

RESULTS

The most frequent underlying heart disease was Brugada/J wave syndrome (n = 7). During a median follow-up period of 1188 days, an OS was observed in six patients (28.6%). The QRS amplitude in synthesized V7 lead (synV7) was significantly lower in the OS group than in the non-OS group (0.59 ± 0.17 vs. 0.91 ± 0.35 mV, p = 0.019). The optimal cutoff value of synV7 QRS amplitude was 0.61 mV, with a sensitivity of 80.0% and a specificity of 83.7% for predicting an OS. Univariate logistic analysis showed that a synV7 QRS amplitude of <0.61 mV was only associated with an OS (odd ratio, 20.0; 95% confidence interval, 1.66-241.72; p = 0.018).

CONCLUSIONS

In patients with S-ICDs, an OS was not a rare complication during long-term follow-up. A low synV7 QRS amplitude was associated with a high OS incidence.

International Society for Heart and Lung Transplantation Guidelines for the Evaluation and Care of Cardiac Transplant Candidates-2024

The "International Society for Heart and Lung Transplantation Guidelines for the Evaluation and Care of Cardiac Transplant Candidates-2024" updates and replaces the "Listing Criteria for Heart Transplantation: International Society for Heart and Lung Transplantation Guidelines for the Care of Cardiac Transplant Candidates-2006" and the "2016 International Society for Heart Lung Transplantation Listing Criteria for Heart Transplantation: A 10-year Update." The document aims to provide tools to help integrate the numerous variables involved in evaluating patients for transplantation, emphasizing updating the collaborative treatment while waiting for a transplant. There have been significant practice-changing developments in the care of heart transplant recipients since the publication of the International Society for Heart and Lung Transplantation (ISHLT) guidelines in 2006 and the 10-year update in 2016. The changes pertain to 3 aspects of heart transplantation: (1) patient selection criteria, (2) care of selected patient populations, and (3) durable mechanical support. To address these issues, 3 task forces were assembled. Each task force was cochaired by a pediatric heart transplant physician with the specific mandate to highlight issues unique to the pediatric heart transplant population and ensure their adequate representation. This guideline was harmonized with other ISHLT guidelines published through November 2023. The 2024 ISHLT guidelines for the evaluation and care of cardiac transplant candidates provide recommendations based on contemporary scientific evidence and patient management flow diagrams. The American College of Cardiology and American Heart Association modular knowledge chunk format has been implemented, allowing guideline information to be grouped into discrete packages (or modules) of information on a disease-specific topic or management issue. Aiming to improve the quality of care for heart transplant candidates, the recommendations present an evidence-based approach.

Ertugliflozin to Reduce Arrhythmic Burden in Patients with ICDs/CRT-Ds

BACKGROUND

Sodium-glucose cotransporter 2 inhibitors (SGLT2is) have beneficial pleiotropic effects, contributing to improved cardiovascular and renal outcomes for patients with and without diabetes. The impact of SGLT2is on arrhythmic burden remains largely unexplored through randomized trials.

METHODS

In this multicenter, double-blind, randomized, placebo-controlled trial, we investigated the effects of ertugliflozin on arrhythmic burden among patients with heart failure with an ejection fraction less than 50%. All patients had an implantable cardioverter-defibrillator (ICD) with or without a cardiac resynchronization therapy device (CRT-D) and were randomized (1:1) to receive either ertugliflozin 5 mg once daily or placebo. The primary end point was the number of incident sustained (>30 seconds) ventricular tachycardia or ventricular fibrillation events from baseline to week 52. Secondary end points included the total number of non-sustained ventricular tachycardias, appropriate ICD therapies, changes in N-terminal pro-brain-type natriuretic peptide (NTproBNP) levels, and the number of heart failure hospitalizations.

RESULTS

Randomization was prematurely terminated, after class IA guideline recommendations were published for SGLT2is in patients with heart failure regardless of the ejection fraction. The final analysis included 46 patients (11% of the originally planned sample size). The yearly rate of the primary end point was 3.5 (95% confidence interval [CI] 2.8 to 4.4) with ertugliflozin compared with 13.3 with placebo (95% CI 11.8 to 14.8; rate ratio 0.16, 95% CI 0.04 to 0.61; P<0.001). There were no apparent differences in appropriate ICD therapies, hospitalizations, NTproBNP levels, or predefined adverse and serious adverse events.

CONCLUSIONS

Ertugliflozin reduced sustained ventricular tachycardia or ventricular fibrillation events in adults with heart failure and an ICD compared with placebo; however, our trial ended early and thus results should be interpreted with caution. (Funded by Investigator-initiated Studies Program of Merck Sharp & Dohme Corp and Pfizer; EudraCT number, 2020-002581-14; ClinicalTrials.gov number NCT04600921.).

Mechanisms behind the high mortality rate in chronic Chagas cardiomyopathy: Unmasking a three-headed monster

Chagas disease is a neglected tropical disease caused by the parasite Trypanosoma cruzi. Chronic Chagas cardiomyopathy (CCC), the most severe form of target organ involvement in Chagas disease, is characterized by a complex pathophysiology and a unique phenotype that differentiates it from other cardiomyopathies, highlighting its worse prognosis compared to other aetiologies of heart failure. The three pathophysiological mechanisms with the largest impact on this differential mortality include rapidly progressive heart failure, a high incidence of stroke, and a high burden of ventricular arrhythmias. However, despite significant advances in understanding the unique molecular circuits underlying these mechanisms, the new knowledge acquired has not been efficiently translated into specific diagnostic and therapeutic approaches for this unique cardiomyopathy. The lack of dedicated clinical trials and the limited CCC-specific risk stratification tools available are evidence of this reality. This review aims to provide an updated perspective of the evidence and pathophysiological mechanisms associated with the higher mortality observed in CCC compared to other cardiomyopathies and highlight opportunities in the diagnostic and therapeutic approaches of the disease.

Prognostic value of ventricular arrhythmia in early post-infarction left ventricular dysfunction: the French nationwide WICD-MI study

BACKGROUND AND AIMS

Prophylactic implantable cardioverter-defibrillators (ICDs) are not recommended until left ventricular ejection fraction (LVEF) has been reassessed 40 to 90 days after an acute myocardial infarction. In the current therapeutic era, the prognosis of sustained ventricular arrhythmias (VAs) occurring during this early post-infarction phase (i.e. within 3 months of hospital discharge) has not yet been specifically evaluated in post-myocardial infarction patients with impaired LVEF. Such was the aim of this retrospective study.

METHODS

Data analysis was based on a nationwide registry of 1032 consecutive patients with LVEF ≤ 35% after acute myocardial infarction who were implanted with an ICD after being prescribed a wearable cardioverter-defibrillator (WCD) for a period of 3 months upon discharge from hospital after the index infarction.

RESULTS

ICDs were implanted either because a sustained VA occurred while on WCD (VA+/WCD, n = 72) or because LVEF remained ≤35% at the end of the early post-infarction phase (VA-/WCD, n = 960). The median follow-up was 30.9 months. Sustained VAs occurred within 1 year after ICD implantation in 22.2% and 3.5% of VA+/WCD and VA-/WCD patients, respectively (P < .0001). The adjusted multivariable analysis showed that sustained VAs while on WCD independently predicted recurrence of sustained VAs at 1 year (adjusted hazard ratio [HR] 6.91; 95% confidence interval [CI] 3.73-12.81; P < .0001) and at the end of follow-up (adjusted HR 3.86; 95% CI 2.37-6.30; P < .0001) as well as 1-year mortality (adjusted HR 2.86; 95% CI 1.28-6.39; P = .012).

CONCLUSIONS

In patients with LVEF ≤ 35%, sustained VA during the early post-infarction phase is predictive of recurrent sustained VAs and 1-year mortality.

Magnetic Resonance-Guided Stereotactic Radioablation for Septal Ventricular Tachycardias

BACKGROUND

Stereotactic arrhythmia radioablation (STAR) was introduced to treat ventricular tachycardia (VT) refractory to catheter ablation. No data are now available in the septal VT substrate setting, representing a challenge when using conventional techniques.

OBJECTIVES

This study sought to evaluate the arrhythmic burden in patients with septal VT treated with magnetic resonance-guided STAR (MRgSTAR).

METHODS

We enrolled consecutive patients with septal VT substrate. The therapy target was achieved by combining anatomic/functional and electrophysiologic information. Patients were treated with a single fraction of 25 Gy adopting MRgSTAR. All patients were clinically followed up, and all implantable cardiac devices were remotely monitored. The efficacy outcome included recurrences of any sustained VT beyond the 6-week blanking period after MRgSTAR. The safety outcome was the incidence of adverse events and atrioventricular block.

RESULTS

We included 11 patients with septal substrate VT (median age: 68 years; Q1-Q3: 64.5-78 years; 100% male). Clinical presentation was an electrical storm in 81.8% of patients. No complications occurred after MRgSTAR, and 6 (54.5%) patients were discharged on the same day of treatment. During a mean follow-up of 12 ± 6 months, the efficacy outcome occurred in 3 (27.3%) cases. A significative reduction of implantable cardioverter-defibrillator (ICD) therapy (23.6 before MRgSTAR vs 1.7 after MRgSTAR; P < 0.001) was observed. Left ventricular ejection fraction increased significantly after treatment (38% [Q1-Q3: 33.5%-42.0%] before MRgSTAR vs 43.8% [Q1-Q3: 35%-47%] after MRgSTAR; P = 0.04). No adverse effects were observed in the implantable cardioverter-defibrillator and lead system; in the 7 patients with preserved atrioventricular conduction, no atrioventricular block was reported.

CONCLUSIONS

MRgSTAR represents a safe and effective strategy for treating septal VT.

Outcomes of Atrial Fibrillation Ablation in Heart Failure Subtypes

BACKGROUND

Catheter ablation (CA) improves clinical outcomes in patients with atrial fibrillation (AF) and heart failure (HF) with reduced ejection fraction (HFrEF). We aimed to evaluate the impact of CA on clinical and quality-of-life outcomes across HF subtypes.

METHODS

All patients undergoing AF ablation at a tertiary center were enrolled in a prospective registry and included in this study (2013-2021). The primary end point was AF recurrence. Secondary end points included AF-related hospitalizations and quality-of-life outcomes. Patients were categorized according to their HF status: no HF, HFrEF, HF with mildly reduced ejection fraction (HFmrEF), and HF with preserved ejection fraction (HFpEF).

RESULTS

A total of 7020 patients were included (80% no HF, 8% HFrEF, 7% HFmrEF, and 5% HFpEF). Over 3 years, the cumulative incidence of AF recurrence after ablation was as follows: HFpEF (53%), HFmrEF (41%), HFrEF (41%), and no HF (34%); P<0.01. Multivariable Cox analyses confirmed these findings using no HF group as reference (HFpEF: hazard ratio, 1.47 [95% CI, 1.21-1.78]; HFmrEF: hazard ratio, 1.23 [95% CI, 1.04-1.45]; and HFrEF: hazard ratio, 1.17 [95% CI, 1.01-1.37]; P<0.05 for all). In all groups, CA resulted in a significant reduction of AF-related hospitalization (mean rate per 1 patient-years [before and after CA]; HFpEF [1.8 versus 0.3], HFmrEF [1.1 versus 0.2], HFrEF [1.1 versus 0.2], and no HF [1 versus 0.1]; P<0.01 for each comparison) and significant improvement in quality of life as measured by both the AF symptom severity score and the AF burden score (P<0.01 for the comparison between baseline and follow-up for each score when tested separately).

CONCLUSIONS

AF recurrence rates after CA were higher in patients with HF compared with those without HF, with patients with HFpEF being at the highest risk of recurrence. Nonetheless, CA was associated with a significant reduction in AF symptoms, AF-related hospitalization, and HF symptoms in most patients irrespective of HF subtypes.

Mortality in Recipients of Durable Left Ventricular Assist Devices Undergoing Ventricular Tachycardia Ablation

BACKGROUND

Left ventricular assist device (LVAD) recipients have a higher incidence of ventricular tachycardia (VT). However, the role of VT ablation in this population is not well-established.

OBJECTIVES

This single-center retrospective cohort study sought to examine the impact of post-LVAD implant VT ablation on survival.

METHODS

This retrospective study examined a cohort of patients that underwent LVAD implantation at Baylor St. Luke's Medical Center and Texas Heart Institute between January 2011 and January 2021. All-cause estimated mortality was compared across LVAD recipients based on the incidence of VT, timing of VT onset, and the occurrence and timing of VT ablation utilizing Kaplan-Meier survival analysis and Cox proportional hazards models.

RESULTS

Post-implant VT occurred in 53% of 575 LVAD recipients. Higher mortality was seen among patients with post-implant VT within a year of implantation (HR: 1.62 [95% CI: 1.15-2.27]). Among this cohort, patients who were treated with a catheter ablation had superior survival compared with patients treated with medical therapy alone for the 45 months following VT onset (HR: 0.48 [95% CI: 0.26-0.89]). Moreover, performance of an ablation in this population aligned mortality rates with those who did not experience post-implant VT (HR: 1.18 [95% CI: 0.71-1.98]).

CONCLUSIONS

VT occurrence within 1 year of LVAD implantation was associated with worse survival. However, performance of VT ablation in this population was correlated with improved survival compared with medical management alone. Among patients with refractory VT, catheter ablation aligned survival with other LVAD participants without post-implant VT. Catheter ablation of VT is associated with improved survival in LVAD recipients, but further prospective randomized studies are needed to compare VT ablation to medical management in LVAD recipients.

Catheter ablation as first-line treatment for ventricular tachycardia in patients with structural heart disease and preserved left ventricular ejection fraction: a systematic review and meta-analysis

In this systematic review and meta-analysis, we aim to evaluate the efficacy and safety of catheter ablation as the first-line treatment of ventricular tachycardia (VT) in patients with structural heart disease (SHD) and preserved left ventricular ejection fraction (LVEF). Patients with SHD are particularly susceptible to VT, a condition that increases the risk of sudden cardiac death (SCD). Implantable cardioverter-defibrillators (ICDs) can terminate VT and prevent SCD but do not prevent VT recurrence. The efficacy and safety of CA as a first-line treatment in SHD patients with preserved LVEF remain unclear. We searched PubMed/Medline, EMBASE, Web of Science, and Cochrane CENTRAL for studies reporting the outcomes of CA therapy in patients with VT and preserved LVEF, published up to January 19, 2023. The primary outcome was the incidence of SCD following catheter ablation as the first-line treatment of VT in patients with SHD and preserved LVEF. Secondary outcomes included all-cause mortality, VT recurrence, procedural complications, CA success rate, and ICD implantation after catheter ablation. We included seven studies in the meta-analysis, encompassing a total of 920 patients. The pooled success rate of catheter ablation was 84.6% (95% CI 67.2-93.6). Complications occurred in 6.4% (95% CI 4.0-9.9) of patients, and 13.9% (95% CI 10.1-18.8) required ICD implantation after ablation. VT recurrence was observed in 23.2% (95% CI 14.8-34.6) of patients, while the rate of sudden cardiac death (SCD) was 3.1% (95% CI 1.7-5.6). The overall prevalence of all-cause mortality in this population was 5% (95% CI 1.8-13). CA appears promising as a first-line VT treatment in patients with SHD and preserved LVEF, especially for monomorphic hemodynamically tolerated VT. However, due to the lack of direct comparisons with ICDs and anti-arrhythmic drugs, further research is needed to confirm these findings.

Predictors of Shock-Reduction Programming and Its Impact on Implantable Cardioverter-Defibrillator Therapies and Mortality: The CERTITUDE Registry

BACKGROUND

Shock-reduction implantable cardioverter-defibrillator programming (SRP) was associated with fewer therapies and improved survival in randomized controlled trials, but real-world studies investigating SRP and associated outcomes are limited.

METHODS AND RESULTS

The BIOTRONIK CERTITUDE registry was linked with the Medicare database. We included all patients with an implantable cardioverter-defibrillator implanted between August 22, 2012 and September 30, 2021 in the United States. SRP was defined as programming to either a therapy rate cutoff ≥188 beats per minute or number of intervals to detection ≥30/40 for treatment. Among 6781 patients (mean 74±9 years; 27% women), 3393 (50%) had SRP. Older age, secondary prevention indication, and device implantation in the southern or western United States were associated with lower use of SRP. The cumulative incidence rate of implantable cardioverter-defibrillator shocks was lower in the SRP group (5.1% shocks/patient year) compared with the non-SRP group (7.2% shocks/patient year) (adjusted hazard ratio [HR], 0.83 [95% CI, 0.73-0.96]; P=0.005). Over a median follow-up of 2.9 years, 739 deaths occurred in the SRP group and 822 deaths occurred in the non-SRP group (adjusted HR, 0.97 [95% CI, 0.88-1.07]; P=0.569). SRP was associated with a lower all-cause mortality among patients without ischemic heart disease compared with patients with ischemic heart disease (adjusted HR, 0.64 [95% CI, 0.48-0.87] versus adjusted HR, 1.02 [95% CI, 0.92-1.14]; Pinteraction=0.004).

CONCLUSIONS

Adoption of SRP is low in real-world clinical practice. Age, clinical variables, and geographic factors are associated with use of SRP. In this study, SRP-associated decrease in mortality was limited to patients without ischemic heart disease.

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.

Long-term outcomes of ventricular tachycardia ablation in repaired tetralogy of Fallot: Systematic review and meta-analysis

Background

Ventricular tachycardia (VT) remains a risk in repaired Tetralogy of Fallot (rTOF); however, long-term benefits of VT ablation have not been established. This study compares the outcomes of rTOF patients with and without VT ablation.

Methods

We searched multiple databases examining the outcomes of rTOF patients who had undergone VT ablation compared to those without ablation. Primary outcomes were VT recurrence, sudden cardiac death (SCD), and all-cause mortality. Subgroup analysis was conducted based on the type of ablation (catheter and surgical). Slow-conducting anatomical isthmus (SCAI)-based catheter ablation (CA) was also analyzed separately. The secondary outcome was the risk factors for the pre-ablation history of VT.

Results

Fifteen cohort studies with 1459 patients were included, 21.4% exhibited VTs. SCAI was found in 30.4% of the population, with 3.7% of non-inducible VT. Factors significantly associated with VT before ablation included a history of ventriculostomy, QRS duration ≥180 ms, fragmented QRS, moderate to severe pulmonary regurgitation, high premature ventricular contractions burden, late gadolinium enhancement, and SCAI. Ablation was only beneficial in reducing VTs recurrence in SCAI-based CA (risk ratio (RR) 0.11; 95% CI 0.03 to 0.33. p < 0.001; I2 = 0%) with no recurrence in patients with preventive ablation (mean follow-up time 91.14 ± 77.81 months). The outcomes of VT ablation indicated a favorable trend concerning SCD and all-cause mortality (RR 0.49 and 0.44, respectively); however, they were statistically insignificant.

Conclusions

SCAI-based CA has significant advantages in reducing VT recurrence in rTOF patients. Risk stratification plays a key role in determining the decision to perform ablation.

Utility of an Externalized Temporary Transvenous Implantable Cardioverter-defibrillator System in the Setting of Ventricular Tachycardia Storm and Concurrent Device Infection Requiring Extraction

With the expanding use of cardiac implantable electronic device (CIED) therapy, intravascular device infections are becoming more common. In the case of transvenous implantable cardioverter-defibrillator (ICD) infections requiring extraction for bacterial clearance, there remains no standard method to deliver temporary ICD therapy following device removal. We present a case of persistent bacteremia complicated by monomorphic ventricular tachycardia (VT) electrical storm where biventricular ICD system extraction was performed and a temporary transvenous dual-coil lead with an externalized ICD generator was used to treat VT episodes prior to the re-implantation of a new permanent system. This case demonstrates the utility of a temporary externalized transvenous ICD system in the successful detection and pace-termination of VT, thereby reducing episodes of painful and potentially harmful external defibrillator shocks during the treatment of CIED infection.

Fifteen years of subcutaneous implantable cardioverter-defibrillator therapy: Where do we stand, and what will the future hold?

The subcutaneous implantable cardioverter-defibrillator (S-ICD) has emerged as a feasible alternative to the transvenous ICD in the treatment of ventricular tachyarrhythmias in patients without indications for pacing or cardiac resynchronization therapy. Since its introduction, numerous innovations have been made and clinical experience has been gained, leading to its adoption in current practice and preference in certain populations. Moreover, emerging technologies like the extravascular ICD and the combination of the S-ICD with the leadless pacemaker offer new possibilities for the future. These advancements underscore the evolving role of the S-ICD in management of ventricular tachyarrhythmias. This review outlines implantation considerations, patient selection, and troubleshooting advancements in the last 15 years and provides insights into future perspectives.

Competing risks of monomorphic vs. non-monomorphic ventricular arrhythmias in primary prevention implantable cardioverter-defibrillator recipients: Global Electrical Heterogeneity and Clinical Outcomes (GEHCO) study

AIMS

Ablation of monomorphic ventricular tachycardia (MMVT) has been shown to reduce shock frequency and improve survival. We aimed to compare cause-specific risk factors for MMVT and polymorphic ventricular tachycardia (PVT)/ventricular fibrillation (VF) and to develop predictive models.

METHODS AND RESULTS

The multicentre retrospective cohort study included 2668 patients (age 63.1 ± 13.0 years; 23% female; 78% white; 43% non-ischaemic cardiomyopathy; left ventricular ejection fraction 28.2 ± 11.1%). Cox models were adjusted for demographic characteristics, heart failure severity and treatment, device programming, and electrocardiogram metrics. Global electrical heterogeneity was measured by spatial QRS-T angle (QRSTa), spatial ventricular gradient elevation (SVGel), azimuth, magnitude (SVGmag), and sum absolute QRST integral (SAIQRST). We compared the out-of-sample performance of the lasso and elastic net for Cox proportional hazards and the Fine-Gray competing risk model. During a median follow-up of 4 years, 359 patients experienced their first sustained MMVT with appropriate implantable cardioverter-defibrillator (ICD) therapy, and 129 patients had their first PVT/VF with appropriate ICD shock. The risk of MMVT was associated with wider QRSTa [hazard ratio (HR) 1.16; 95% confidence interval (CI) 1.01-1.34], larger SVGel (HR 1.17; 95% CI 1.05-1.30), and smaller SVGmag (HR 0.74; 95% CI 0.63-0.86) and SAIQRST (HR 0.84; 95% CI 0.71-0.99). The best-performing 3-year competing risk Fine-Gray model for MMVT [time-dependent area under the receiver operating characteristic curve (ROC(t)AUC) 0.728; 95% CI 0.668-0.788] identified high-risk (> 50%) patients with 75% sensitivity and 65% specificity, and PVT/VF prediction model had ROC(t)AUC 0.915 (95% CI 0.868-0.962), both satisfactory calibration.

CONCLUSION

We developed and validated models to predict the competing risks of MMVT or PVT/VF that could inform procedural planning and future randomized controlled trials of prophylactic ventricular tachycardia ablation.

CLINICAL TRIAL REGISTRATION

URL:www.clinicaltrials.gov Unique identifier:NCT03210883.

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.

Association of device detected atrial and ventricular tachyarrhythmia with adverse events in patients with an implantable cardioverter-defibrillator

INTRODUCTION

Heart failure patients with a history of atrial fibrillation (AF) and ventricular tachycardia/ventricular fibrillation (VT/VF) are known to have worse outcomes. However, there are limited data on the temporal relationship between development of these arrhythmias and the risk of subsequent congestive heart failure (CHF) exacerbation and death.

METHODS

The study cohort comprised 5511 patients implanted with an implantable cardioverter-defibrillator (ICD) in landmark clinical trials (MADIT-II, MADIT-RISK, MADIT-CRT, MADIT-RIT, and RAID) who were in sinus rhythm at enrollment. Multivariate cox analysis was performed to evaluate the time-dependent association between development of in-trial device detected AF and VT/VF with subsequent CHF exacerbation and death.

RESULTS

Multivariate analysis showed that AF occurrence and VT/VF occurrence were both associated with a similar magnitude of risk for subsequent CHF exacerbation (HR = 1.73 and 1.87 respectively, p < .001 for both). In contrast, only in-trial VT/VF was associated with a significant > two-fold increase in the risk of subsequent mortality (HR = 2.13, p < .001) whereas AF occurrence was not associated with a significant mortality increase after adjustment for in-trial VT/VF (HR = 1.36, p = .096).

CONCLUSION

Our findings from a large cohort of ICD recipients enrolled in landmark clinical trials show that device detected AF and VT/VF can be used to identify patients with increased risk for CHF exacerbation and mortality. These findings suggest a need for early intervention in CHF patients who develop device-detected atrial and ventricular tachyarrhythmias.

Active Arrhythmia Pattern: A Novel Predictor of ICD Shocks-A Subanalysis From the PARTITA Study

BACKGROUND

In the PARTITA trial (Does Timing of Ventricular Tachycardia Ablation Affect Prognosis in Patients With an Implantable Cardioverter Defibrillator?), antitachycardia pacing (ATP) predicted the occurrence of implantable cardioverter defibrillator (ICD) shocks. Catheter ablation of ventricular tachycardia after the first shock reduced the risk of death or worsening heart failure. A threshold of ATPs that might warrant an ablation procedure before ICD shocks is unknown. Our aim was to identify a threshold of ATPs and clinical features that predict the occurrence of shocks and cardiovascular events.

METHODS

We analyzed data from 517 patients in phase A of the PARTITA study. We used classification and regression tree analysis to develop and test a risk stratification model based on arrhythmia patterns and clinical data to predict ICD shocks. Secondary end points were worsening heart failure and cardiovascular hospitalization.

RESULTS

Classification and regression tree classified patients into 6 leaves by increasing shock probability. Patients treated with ≥5 ATPs in 6 months (active arrhythmia pattern) had the highest risk of ICD shocks (93% and 86%, training and testing samples, respectively). Patients without ATPs had the lowest (1% and 2%). Other predictors included left ventricle ejection fraction<35%, age of <60 years, and obesity. Survival analysis revealed a higher risk of worsening heart failure (hazard ratio, 5.45 [95% CI, 1.62-18.4]; P=0.006) and cardiovascular hospitalization (hazard ratio, 7.29 [95% CI, 3.66-14.5]; P<0.001) for patients with an active arrhythmia pattern compared with those without ATPs.

CONCLUSIONS

Patients with an active arrhythmia pattern (≥5 ATPs in 6 months) are associated with an increased risk of ICD shocks, as well as heart failure hospitalization and cardiovascular hospitalization. These data suggest that additional treatments may be helpful to this high-risk group as a preventive strategy to reduce the incidence of major events. Further prospective randomized trials are needed to confirm the benefits of early ventricular tachycardia ablation in this setting.

Radiation therapy for ventricular arrhythmias

Ventricular arrhythmias (VA) can be life-threatening arrhythmias that result in significant morbidity and mortality. Catheter ablation (CA) is an invasive treatment modality that can be effective in the treatment of VA where medications fail. Recurrence occurs commonly following CA due to an inability to deliver lesions of adequate depth to cauterise the electrical circuits that drive VA or reach areas of scar responsible for VA. Stereotactic body radiotherapy is a non-invasive treatment modality that allows volumetric delivery of energy to treat circuits that cannot be reached by CA. It overcomes the weaknesses of CA and has been successfully utilised in small clinical trials to treat refractory VA. This article summarises the current evidence for this novel treatment modality and the steps that will be required to bring it to the forefront of VA treatment.

Exploring the Full Potential of Radiofrequency Technology: A Practical Guide to Advanced Radiofrequency Ablation for Complex Ventricular Arrhythmias

PURPOSE OF REVIEW

Percutaneous radiofrequency (RF) catheter ablation is an established strategy to prevent ventricular tachycardia (VT) recurrence and ICD shocks. Yet delivery of durable lesion sets by means of traditional unipolar radiofrequency ablation remains challenging, and left ventricular transmurality is rarely achieved. Failure to ablate and eliminate functionally relevant areas is particularly common in deep intramyocardial substrates, e.g. septal VT and cardiomyopathies. Here, we aim to give a practical-orientated overview of advanced and emerging RF ablation technologies to target these complex VT substrates. We summarize recent evidence in support of these technologies and share experiences from a tertiary VT centre to highlight important "hands-on" considerations for operators new to advanced RF ablation strategies.

RECENT FINDINGS

A number of innovative and modified radiofrequency ablation approaches have been proposed to increase energy delivery to the myocardium and maximize RF lesion dimensions and depth. These include measures of impedance modulation, combinations of simultaneous unipolar ablations or true bipolar ablation, intramyocardial RF delivery via wires or extendable RF needles and investigational linear or spherical catheter designs. Recent new clinical evidence for the efficacy and safety of these investigational technologies and strategies merits a re-evaluation of their role and clinic application for percutaneous VT ablations. Complexity of substrates targeted with percutaneous VT ablation is increasing and requires detailed preprocedural imaging to characterize the substrate to inform the procedural approach and selection of ablation technology. Depending on local experience, options for additional and/or complementary interventional treatments should be considered upfront in challenging substrates to improve the success rates of index procedures. Advanced RF technologies available for clinical VT ablations include impedance modulation via hypotonic irrigation or additional dispersive patches and simultaneous unipolar as well as true bipolar ablation. Promising investigational RF technologies involve an extendable needle RF catheter, intramyocardial RF delivery over intentionally perforated wires as well as a variety of innovative ablation catheter designs including multipolar linear, spherical and partially insulated ablation catheters.

Comparison of novel intrinsic versus conventional antitachycardia pacing for ventricular tachycardia among implantable cardioverter-defibrillator recipients

INTRODUCTION

Intrinsic antitachycardia pacing (iATP) is a novel automated antitachycardia pacing (ATP) that provides individual treatment to terminate ventricular tachycardia (VT). However, the clinical efficacy of iATP in comparison with conventional ATP is unknown. We aim to compare the termination rate of VT between iATP and conventional ATP in patients with implantable cardioverter-defibrillators using a unique setting of different sequential orders of both ATP algorisms.

METHODS

Patients with the iATP algorithm were assigned to iATP-first and conventional ATP-first groups sequentially. In the iATP-first group, a maximum of seven iATP sequences were delivered, followed by conventional burst and ramp pacing. In contrast, in the conventional ATP-first group, two bursts and ramp pacing were initially programmed, followed by iATP sequences. We compared the success rates of VT termination in the first and secondary programmed ATP zones between the two groups.

RESULTS

Fifty-eight and 56 patients were enrolled in the iATP-first and conventional ATP-first groups, and 67 and 44 VTs were analyzed in each group, respectively. At the first single ATP therapy, success rates were 64% and 70% in the iATP and conventional groups, respectively. At the end of the first iATP treatment zone, the success rate increased from 64% to 85%. Moreover, secondary iATP therapy following the failure of conventional ATPs increased the success rate from 80% to 93%. There was a significant benefit of alternative iATP for VT termination compared to secondary conventional ATP (100% vs. 33%, p = .028).

CONCLUSIONS

iATP may be beneficial as a secondary therapy after failure of conventional ATP to terminate VT.

A Multicenter Study of Stellate Ganglion Block as a Temporizing Treatment for Refractory Ventricular Arrhythmias

BACKGROUND

Ventricular tachycardia (VT) and ventricular fibrillation (VF) are life-threatening conditions and can be refractory to conventional drug and device interventions. Stellate ganglion blockade (SGB) has been described as an adjunct, temporizing intervention in patients with refractory ventricular arrhythmia. We examined the association of SGB with VT/VF in a multicenter registry.

OBJECTIVES

This study examined the efficacy of SGB for treatment/temporization of refractory VT/VF.

METHODS

The authors present the first analysis from a multicenter registry of patients treated for refractory ventricular arrhythmia at a clinical site in the Czech Republic and the United States. Data were collected between 2016 and 2022. SGB was performed at the bedside by anesthesiologists and/or cardiologists. Outcomes of interest were VT/VF burden and defibrillations at 24 hours before and after SGB.

RESULTS

In total, there were 117 patients with refractory ventricular arrhythmias treated with SGB at Duke (n = 49) and the Institute for Clinical and Experimental Medicine (n = 68). The majority of patients were male (94.0%), were White (87.2%), and had an implantable cardioverter-defibrillator (70.1%). The most common etiology of heart disease was ischemic cardiomyopathy (52.1%), and monomorphic VT was the most common morphology (70.1%). Within 24 hours before SGB (0-24 hours), the median episodes of VT/VF were 7.5 (Q1-Q3: 3.0-27.0), and 24 hours after SGB, the median decreased to 1.0 (Q1-Q3: 0.0-4.5; P < 0.001). At 24 hours before SGB, the median defibrillation events were 2.0 (Q1-Q3: 0.0-8.0), and 24 hours after SGB, the median decreased to 0.0 (Q1-Q3: 0.0-1.0; P < 0.001).

CONCLUSIONS

In the largest cohort of patients with treatment-refractory ventricular arrhythmia, we demonstrate that SGB use was associated with a reduction in the ventricular arrhythmia burden and need for defibrillation therapy.

Impact of ventricular tachycardia ablation in subcutaneous implantable cardioverter defibrillator carriers: a multicentre, international analysis from the iSUSI project

AIMS

Catheter ablation (CA) of ventricular tachycardia (VT) has become an important tool to improve clinical outcomes in patients with appropriate transvenous implantable cardioverter defibrillator (ICD) shocks. The aim of our analysis was to test whether VT ablation (VTA) impacts long-term clinical outcomes even in subcutaneous ICD (S-ICD) carriers.

METHODS AND RESULTS

International Subcutaneous Implantable Cardioverter Defibrillator (iSUSI) registry patients who experienced either an ICD shock or a hospitalization for monomorphic VT were included in this analysis. Based on an eventual VTA after the index event, patients were divided into VTA+ vs. VTA- cohorts. Primary outcome of the study was the occurrence of a combination of device-related appropriate shocks, monomorphic VTs, and cardiovascular mortality. Secondary outcomes were addressed individually. Among n = 1661 iSUSI patients, n = 211 were included: n = 177 experiencing ICD shocks and n = 34 hospitalized for VT. No significant differences in baseline characteristics were observed. Both the crude and the yearly event rate of the primary outcome (5/59 and 3.8% yearly event rate VTA+ vs. 41/152 and 16.4% yearly event rate in the VTA-; log-rank: P value = 0.0013) and the cardiovascular mortality (1/59 and 0.7% yearly event rate VTA+ vs. 13/152 and 4.7% yearly event rate VTA-; log-rank P = 0.043) were significantly lower in the VTA + cohort. At multivariate analysis, VTA was the only variable remaining associated with a lower incidence of the primary outcome [adjusted hazard ratio 0.262 (0.100-0.681), P = 0.006].

CONCLUSION

In a real-world registry of S-ICD carriers, the combined study endpoint of arrhythmic events and cardiovascular mortality was lower in the patient cohort undergoing VTA at long-term follow-up.

CLINICALTRIALS.GOV IDENTIFIER

NCT0473876.

Managing ventricular arrhythmias and implantable cardiac defibrillator shocks after left ventricular assist device implantation

Continuous flow left ventricular assist devices (CF-LVADs) have been shown to reduce mortality and morbidity in patients with advanced heart failure with reduced ejection fraction. However, ventricular arrhythmias (VA) are common, are mostly secondary to underlying myocardial scar, and have a higher incidence in patients with pre-LVAD VA. Sustained VA is well tolerated in the LVAD patient but can result in implantable defibrillator (ICD) shocks, right ventricular failure, hospitalizations, and reduced quality of life. There is limited data regarding best practices for the medical management of VA as well as the role for procedural interventions in patients with uncontrolled VA and/or ICD shocks. Vast majority of CF-LVAD patients have a preexisting cardiovascular implantable electronic device (CIED) and ICD and/or cardiac resynchronization therapies are continued in many. Several questions, however, remain regarding the efficacy of ICD and CRT following CF-LVAD. Moreover, optimal CIED programming after CF-LVAD implantation. Therefore, the primary objective of this review article is to provide the most up-to-date evidence and to provide guidance on the clinical significance, pathogenesis, predictors, and management strategies for VA and ICD therapies in the CF-LVAD population. We also discuss knowledge gaps as well as areas for future research.

Implications of ventricular arrhythmia after cardiac resynchronization therapy

BACKGROUND

Conflicting data are available on whether ventricular arrhythmia (VA) or shock therapy increases mortality. Although cardiac resynchronization therapy (CRT) reduces the risk of VA, little is known about the prognostic value of VA among patients with CRT devices.

OBJECTIVES

The purpose of this study was to evaluate the implications of VA as a prognostic marker for CRT.

METHODS

We investigated 330 CRT patients within 1 year after CRT device implantation. The primary endpoint was the composite endpoint of all-cause death or hospitalization for heart failure.

RESULTS

Forty-three patients had VA events. These patients had a significantly higher risk of the primary endpoint, even among CRT responders (P = .009). Fast VA compared to slow VA was associated with an increased risk of the primary endpoint (hazard ratio [HR] 2.14; 95% confidence interval [CI] 1.06-4.34; P = .035). Shock therapy was not associated with a primary endpoint (shock therapy vs antitachycardia pacing: HR 1.49; 95% CI 0.73-3.03; P = .269). The patients with VA had a lower prevalence of response to CRT (23 [53%] vs 202 [70%]; P = .031) and longer left ventricular paced conduction time (174 ± 23 ms vs 143 ± 36 ms; P = .003) than the patients without VA.

CONCLUSION

VA occurrence within 1 year was related to paced electrical delay and poor response to CRT. VA could be associated with poor prognosis among CRT patients.

Two-incision versus three-incision implantation technique of subcutaneous implantable cardioverter defibrillator: Systematic review and meta-analysis of 2076 patients

INTRODUCTION

The implantable cardioverter-defibrillator (ICD) was designed to detect and treat ventricular arrhythmias, which account for nearly half of all cardiovascular fatalities. Transvenous ICD (TV-ICD) complications were reduced by introducing subcutaneous ICD (S-ICD). S-ICD can be implanted using a three (3IT)- or two (2IT)-incision technique. This systematic review and meta-analysis was conducted to compare the 3IT to the 2IT.

METHODS

We searched medical electronic databases of Cochrane Central, Embase, PubMed, Scopus, and Web of Science (WOS) from the study's inception until March 8, 2023. We compared 2IT and 3IT techniques of S-ICDs in terms of procedural, safety, and efficacy outcomes. We used Review Manager software for the statistical analysis. We calculated the risk ratio (RR) with its 95% confidence interval (CI) for dichotomous variables; and the mean difference with its 95% CI for continuous variables. We measured the heterogeneity using the chi-squared and I-squared tests. If the data were heterogeneous, the random-effect (RE) model was applied; otherwise, the fixed-effect model (FE) was used.

RESULTS

We included three retrospective observational studies of 2076 patients, 1209 in the 2IT group and 867 in the 3IT. There was no statistically significant difference in erosion after S-ICD when 2IT compared with 3IT (RR = 0.27, 95% CI: [0.07, 1.02]; P = .05) (I2 = 0%, P = .90). There was no difference in risk of infection, lead dislocation, or inappropriate shock with either incision technique (RR = 0.78, 95% CI: [0.48, 1.29]; P = .34) (I2 = 0%, P = .71) and (RR = 0.37, 95% CI: [0.02, 8.14]; P = .53) (I2 = 66%, P = .05) respectively. Our meta-analysis showed that the efficacy of both techniques is comparable; Appropriate shock (RR = 0.94, 95% CI: [0.78, 1.12]; P = .48) (I2 = 0%, P = .81) and first shock efficacy (RR = 0.89, 95% CI: [0.44, 1.82]; P = .76) (I2 = 0%, P = .87).

CONCLUSION

2IT and 3IT of S-ICD have comparable efficacy and complication rates; however, the 3IT exposes patients to an additional incision without any additional benefits. These findings may provide clinicians with a simpler method for subcutaneous ICD implantation and likely result in improved cosmetic outcomes. Before the 2IT technique can be considered the standard of care, randomized controlled trials (RCTs) must be conducted to assess its long-term safety and efficacy.

Ventricular Tachycardia Catheter Ablation: Retrospective Analysis and Prospective Outlooks-A Comprehensive Review

Ventricular tachycardia is a potentially life-threatening arrhythmia associated with an overall high morbi-mortality, particularly in patients with structural heart disease. Despite their pivotal role in preventing sudden cardiac death, implantable cardioverter-defibrillators, although a guideline-based class I recommendation, are unable to prevent arrhythmic episodes and significantly alter the quality of life by delivering recurrent therapies. From open-heart surgical ablation to the currently widely used percutaneous approach, catheter ablation is a safe and effective procedure able to target the responsible re-entry myocardial circuit from both the endocardium and the epicardium. There are four main mapping strategies, activation, entrainment, pace, and substrate mapping, each of them with their own advantages and limitations. The contemporary guideline-based recommendations for VT ablation primarily apply to patients experiencing antiarrhythmic drug ineffectiveness or those intolerant to the pharmacological treatment. Although highly effective in most cases of scar-related VTs, the traditional approach may sometimes be insufficient, especially in patients with nonischemic cardiomyopathies, where circuits may be unmappable using the classic techniques. Alternative methods have been proposed, such as stereotactic arrhythmia radioablation or radiotherapy ablation, surgical ablation, needle ablation, transarterial coronary ethanol ablation, and retrograde coronary venous ethanol ablation, with promising results. Further studies are needed in order to prove the overall efficacy of these methods in comparison to standard radiofrequency delivery. Nevertheless, as the field of cardiac electrophysiology continues to evolve, it is important to acknowledge the role of artificial intelligence in both the pre-procedural planning and the intervention itself.

Inappropriate shock incidence in patients with subcutaneous implantable cardioverter-defibrillators with concomitant cardiac implantable electronic devices: A single-center cohort study

BACKGROUND

Subcutaneous implantable cardioverter defibrillators (S-ICDs) are occasionally used in combination with other cardiac implantable electronic devices (CIEDs). However, whether the incidence of inappropriate shock increases in patients with S-ICDs and concomitant CIEDs remains unclear. This study aimed to investigate the association between the concomitant use of CIEDs and the incidence of inappropriate shock in patients with current-generation S-ICDs.

METHODS

A total of 127 consecutive patients received an S-ICD. Patients were assigned to two groups depending on concomitant use of CIEDs at the time of S-ICD implantation: patients without other CIEDs (non-combined group, 106 patients) and patients with other CIEDs (combined group, 21 patients). CIEDs included pacemakers, implantable cardioverter defibrillators, cardiac resynchronization therapy pacemakers, and cardiac resynchronization therapy defibrillators. The primary outcome was inappropriate shock, defined as a shock other than ventricular arrhythmia. Hazard ratios and 95% confidence intervals were calculated using a time-varying Cox proportional hazards model which was adjusted for age because age differed between the groups and could be a confounder.

RESULTS

During a median follow-up period of 2.2 years (interquartile range, 1.0-3.4 years), inappropriate shock events occurred in 17 (16%) and five (19%) patients of the non-combined and combined groups, respectively. While the age-adjusted hazard ratio for inappropriate shock was 24% higher in the combined than in the non-combined group (hazard ratio = 1.24, 95% confidence interval, 0.39-3.97), this difference was insignificant (p = .71).

CONCLUSION

The incidence of inappropriate shock did not differ between patients with and without concomitant use of CIEDs, suggesting that S-ICDs could potentially be combined with other CIEDs without increasing the number of inappropriate shocks. Further studies are warranted to confirm the safety and feasibility of concomitant use of S-ICDs and CIEDs.

Machine-Learning-Based Prediction of 1-Year Arrhythmia Recurrence after Ventricular Tachycardia Ablation in Patients with Structural Heart Disease

BACKGROUND

Ventricular tachycardia (VT) recurrence after catheter ablation remains a concern, emphasizing the need for precise risk assessment. We aimed to use machine learning (ML) to predict 1-month and 1-year VT recurrence following VT ablation.

METHODS

For 337 patients undergoing VT ablation, we collected 31 parameters including medical history, echocardiography, and procedural data. 17 relevant features were included in the ML-based feature selection, which yielded six and five optimal features for 1-month and 1-year recurrence, respectively. We trained several supervised machine learning models using 10-fold cross-validation for each endpoint.

RESULTS

We observed 1-month VT recurrence was observed in 60 (18%) cases and accurately predicted using our model with an area under the receiver operating curve (AUC) of 0.73. Input features used were hemodynamic instability, incessant VT, ICD shock, left ventricular ejection fraction, TAPSE, and non-inducibility of the clinical VT at the end of the procedure. A separate model was trained for 1-year VT recurrence (observed in 117 (35%) cases) with a mean AUC of 0.71. Selected features were hemodynamic instability, the number of inducible VT morphologies, left ventricular systolic diameter, mitral regurgitation, and ICD shock. For both endpoints, a random forest model displayed the highest performance.

CONCLUSIONS

Our ML models effectively predict VT recurrence post-ablation, aiding in identifying high-risk patients and tailoring follow-up strategies.

PRecision Event Monitoring for PatienTs with Heart Failure using HeartLogic (PREEMPT-HF) study design and enrolment

AIMS

The HeartLogic multisensor index has been found to be a sensitive predictor of worsening heart failure (HF). However, there is limited data on this index's association and its constituent sensors with HF readmissions.

METHODS AND RESULTS

The PREEMPT-HF study is a global, multicentre, prospective, observational, single-arm, post-market study. HF patients with an implantable defibrillator device or cardiac resynchronization therapy with defibrillator with HeartLogic capabilities were eligible if sensor data collection was turned on and the HeartLogic feature was not enabled. Thus, the HeartLogic Index/alert and heart sounds sensor trends were unavailable via the LATITUDE remote monitoring system to clinicians (blinded). Evaluation of subject medical records at 6 months and a final in-clinic visit at 12 months was required for collection of all-cause hospitalizations and HF outpatient visits. The purpose of this study is exploratory, no formal hypothesis tests are planned, and no adjustment for multiple testing will be performed. A total of 2183 patients were enrolled at 103 sites between June 2018 and June 2020. A significant proportion of the patients were implanted with implantable defibrillator devices (39%) versus cardiac resynchronization therapy with defibrillator (61%); were female (27%); over 65 (61%); New York Heart Association class I (13%), II (53%), and III (33%); ejection fraction < 25% (21%); ischaemic (50%); and with a history of renal dysfunction (23%).

CONCLUSIONS

The PREEMPT study will provide clinical data and blinded sensor trends for the characterization of sensor changes with HF readmission, tachyarrhythmias, and event subgroups. These data may help to refine the clinical use of HeartLogic and to improve patient outcomes.

Rationale and study protocol for the BRITISH randomized trial (Using cardiovascular magnetic resonance identified scar as the benchmark risk indication tool for implantable cardioverter defibrillators in patients with nonischemic cardiomyopathy and severe systolic heart failure)

BACKGROUND

For patients with nonischemic cardiomyopathy (NICM), current guidelines recommend implantable cardioverter defibrillators (ICD) when left ventricular ejection fraction (LVEF) is ≤35%, but the DANISH trial failed to confirm that ICDs reduced all-cause mortality for such patients. Circumstantial evidence suggests that scar on CMR is predictive of sudden and arrhythmic death in this population. The presence of myocardial scar identified by cardiac magnetic resonance imaging (CMR) in patients with NICM and an LVEF ≤35% might identify patients at higher risk of sudden arrhythmic death, for whom an ICD is more likely to reduce all-cause mortality.

METHODS/DESIGN

The BRITISH trial is a prospective, multicenter, randomized controlled trial aiming to enrol 1,252 patients with NICM and an LVEF ≤35%. Patients with a nonischemic scar on CMR will be randomized to either: (1) ICD, with or without cardiac resynchronization (CRT-D), or (2) implantable loop recorder (ILR) or cardiac resynchronization (CRT-P). Patients who are screened for the trial but are found not to be eligible, predominantly due to an absence of scar or those who decline to be randomized will be enrolled in an observational registry. The primary endpoint is all-cause mortality, which we plan to assess at 3 years after the last participant is randomized. Secondary endpoints include clinical outcomes, appropriate and inappropriate device therapies, symptom severity and well-being, device-related complications, and analysis of the primary endpoint by subgroups with other risk markers.

CONCLUSION

The BRITISH trial will assess whether the use of CMR-defined scar to direct ICD implantation in patients with NICM and an LVEF ≤35% is associated with a reduction in mortality.

Effect of ivabradine on ventricular arrhythmias in heart failure patients with reduced ejection fraction

BACKGROUND/INTRODUCTION

Heart failure patients with reduced ejection fraction are at high risk for ventricular arrhythmias and sudden cardiac death. Ivabradine, a specific inhibitor of the If current in the sinoatrial node, provides heart rate reduction in sinus rhythm and angina control in chronic coronary syndromes.

OBJECTIVE

The effect of ivabradine on ventricular arrhythmias in heart failure patients with reduced ejection fraction patients has not been fully elucidated. The aim of this study was to investigate the effect of ivabradine use on life-threatening arrhythmias and long-term mortality in heart failure patients with reduced ejection fraction patients.

METHODS

In this retrospective study, 1,639 patients with heart failure patients with reduced ejection fraction were included. Patients were divided into two groups: ivabradine users and nonusers. Patients presenting with ventricular tachycardia, the presence of ventricular extrasystole, and ventricular tachycardia in 24-h rhythm monitoring, appropriate implantable cardioverter-defibrillator shocks, and long-term mortality outcomes were evaluated according to ivabradine use.

RESULTS

After adjustment for all possible variables, admission with ventricular tachycardia was three times higher in ivabradine nonusers (95% confidence interval 1.5-10.2). The presence of premature ventricular contractions and ventricular tachycardias in 24-h rhythm Holter monitoring was notably higher in ivabradine nonusers. According to the adjusted model for all variables, 4.1 times more appropriate implantable cardioverter-defibrillator shocks were observed in the ivabradine nonusers than the users (95%CI 1.8-9.6). Long-term mortality did not differ between these groups after adjustment for all covariates.

CONCLUSION

The use of ivabradine reduced the appropriate implantable cardioverter-defibrillator discharge in heart failure patients with reduced ejection fraction patients. Ivabradine has potential in the treatment of ventricular arrhythmias in heart failure patients with reduced ejection fraction patients.

Outcomes Comparison of Robot-Assisted and Video-Assisted Thoracoscopic Cardiac Sympathetic Denervation

OBJECTIVE

Cardiac sympathetic denervation (CSD) is a surgical antiadrenergic procedure that can reduce sustained ventricular tachyarrhythmia (VT). Video-assisted thoracoscopic surgery (VATS) is currently the standard approach used in CSD, and the practicality for robot-assisted thoracoscopic surgery (RATS) has yet to be investigated.

METHODS

We conducted a single-center retrospective study of all adult patients (N = 67) who underwent CSD from 2015 to 2021. We compared short-term outcomes of those treated with RATS versus VATS thoracic sympathectomy. For patients with VT, we examined the effectiveness of a RATS approach in reducing implantable cardioverter defibrillator (ICD) shock burden.

RESULTS

A total of 34 patients underwent RATS cardiac denervation, and 33 underwent VATS cardiac denervation. Those undergoing RATS denervation had a significantly shorter procedure duration with a median of 129 min (P = 0.008). Patients receiving the VATS approach were significantly more complicated by pneumothorax (P = 0.004) and overall complications (P = 0.01) when compared with the RATS approach. At 1 year after surgery, both groups had significant reductions in ICD shocks compared with before surgery, both decreasing from a median of 4 to 0 shocks (P < 0.001). In addition, at 1 year after surgery, the percentage of patients with persistent ICD shocks and the median of ICD shocks were similar between the groups.

CONCLUSIONS

The RATS approach to cardiac denervation has similar 1-year follow-up outcomes in reducing recurrent VT as the VATS approach. However, patients undergoing RATS denervation experienced better perioperative outcomes. This shows promise for robotic CSD to be an effective and safe therapeutic option for patients with malignant arrhythmias.

Sacubitril/valsartan and arrhythmic burden in patients with heart failure and reduced ejection fraction: a systematic review and meta-analysis

The aim of this study was to assess whether angiotensin receptor/neprilysin inhibitor (ARNI) decreases ventricular arrhythmic burden compared to angiotensin-converting enzyme inhibitors or angiotensin receptor antagonist (ACE-I/ARB) treatment in chronic heart failure with reduced ejection fraction (HFrEF) patients. Further, we assessed if ARNI influenced the percentage of biventricular pacing. A systematic review of studies (both RCTs and observational studies) including HFrEF patients and those receiving ARNI after ACE-I/ARB treatment was conducted using Medline and Embase up to February 2023. Initial search found 617 articles. After duplicate removal and text check, 1 RCT and 3 non-RCTs with a total of 8837 patients were included in the final analysis. ARNI was associated with a significative reduction of ventricular arrhythmias both in RCT (RR 0.78 (95% CI 0.63-0.96); p = 0.02) and observational studies (RR 0.62; 95% CI 0.53-0.72; p < 0.001). Furthermore, in non-RCTs, ARNI also reduced sustained (RR 0.36 (95% CI 0.2-0.63); p < 0.001), non-sustained VT (RR 0.67 (95% CI 0.57-0.80; p = 0.007), ICD shock (RR 0.24 (95% CI 0.12-0.48; p < 0.001), and increased biventricular pacing (2.96% (95% CI 2.25-3.67), p < 0.001). In patients with chronic HFrEF, switching from ACE-I/ARB to ARNI treatment was associated with a consistent reduction of ventricular arrhythmic burden. This association could be related to a direct pharmacological effect of ARNI on cardiac remodeling.Trial registration: CRD42021257977.

Recurrences of ventricular tachycardia after stereotactic arrhythmia radioablation arise outside the treated volume: analysis of the Swiss cohort

AIMS

Stereotactic arrhythmia radioablation (STAR) has been recently introduced for the management of therapy-refractory ventricular tachycardia (VT). VT recurrences have been reported after STAR but the mechanisms remain largely unknown. We analysed recurrences in our patients after STAR.

METHODS AND RESULTS

From 09.2017 to 01.2020, 20 patients (68 ± 8 y, LVEF 37 ± 15%) suffering from refractory VT were enrolled, 16/20 with a history of at least one electrical storm. Before STAR, an invasive electroanatomical mapping (Carto3) of the VT substrate was performed. A mean dose of 23 ± 2 Gy was delivered to the planning target volume (PTV). The median ablation volume was 26 mL (range 14-115) and involved the interventricular septum in 75% of patients. During the first 6 months after STAR, VT burden decreased by 92% (median value, from 108 to 10 VT/semester). After a median follow-up of 25 months, 12/20 (60%) developed a recurrence and underwent a redo ablation. VT recurrence was located in the proximity of the treated substrate in nine cases, remote from the PTV in three cases and involved a larger substrate over ≥3 LV segments in two cases. No recurrences occurred inside the PTV. Voltage measurements showed a significant decrease in both bipolar and unipolar signal amplitude after STAR.

CONCLUSION

STAR is a new tool available for the treatment of VT, allowing for a significant reduction of VT burden. VT recurrences are common during follow-up, but no recurrences were observed inside the PTV. Local efficacy was supported by a significant decrease in both bipolar and unipolar signal amplitude.

Ventricular arrhythmia detection for contemporary Biotronik and Abbott implantable cardioverter defibrillators with markedly prolonged detection in Biotronik devices

BACKGROUND

Implantable cardioverter defibrillators (ICDs) are typically programed with both ventricular tachycardia (VT) and ventricular fibrillation (VF) treatment zones. Biotronik and Abbott ICDs do not increment the VT counter when the tachycardia accelerates to the VF zone, which could result in a prolonged delay in tachycardia detection.

METHODS

Patients with Biotronik and Abbott ICDs receiving care at Veterans Affairs facilities in Northern California were identified. Patient information and device tracings for patients with any ICD therapies were examined to assess for possible delayed tachycardia detection.

RESULTS

Among 52 patients with Biotronik ICDs, 8 (15%) experienced appropriate ICD therapy over a median follow-up of 29 months. Among 68 patients with Abbott ICDs, 26 (38%) experienced appropriate ICD therapy over a median follow-up of 83 months. Three of the patients with Biotronik ICDs who received appropriate therapy experienced a delay in VT/VF detection due to the tachycardia rate oscillating between the VT and VF treatment zones (longest 31.2 s on detection), compared with four of the patients with Abbott ICDs (longest 4.1 s on the detection and 8 s on redetect). One of the patients with a Biotronik ICD experienced recurrent syncope associated with delayed detection and another died on the day of delayed detection. One of the patients with an Abbott ICD experienced syncope.

CONCLUSIONS

Because contemporary Biotronik and Abbott ICDs freeze the VT counters when tachycardia is in the VF zone, ICD therapies can be markedly delayed when the tachycardia oscillates between the VT and VF zone.

Efficacy and safety of catheter ablation as first-line therapy for the management of ventricular tachycardia

BACKGROUND

Ventricular tachycardia (VT) is associated with significantly increased morbidity and mortality. Catheter ablation (CA) in line with an implantable cardioverter-defibrillator (ICD) is highly effective in VT management; however, it is unknown if CA should be considered as first-line therapy. The aim of this study is to verify the efficacy and safety of CA as first-line therapy for the first VT presentation (as adjunctive to ICD insertion), compared to initial ICD insertion and anti-arrhythmic drug (AAD) therapy.

METHODS

Data from patients with the first presentation for VT from January 2017 to January 2021 was reviewed. Patients were classified as "ablation first" vs "ICD first" groups and compared the clinical outcomes between groups.

RESULTS

One hundred and eighty-four consecutive patients presented with VT; 34 underwent CA as first-line therapy prior to ICD insertion, and 150 had ICD insertion/AAD therapy as first-line. During the median follow-up of 625 days, patients who underwent CA as first-line therapy had significantly higher ventricular arrhythmia (VA)-free survival (91% vs 59%, log-rank P = 0.002) and composite of VA recurrence, cardiovascular hospitalization, transplant, and death (84% vs 54%, log-rank P = 0.01) compared to those who did not undergo CA. Multivariate analysis revealed that first-line CA was the only protective predictor of VA recurrence (hazard ratio (HR) 0.20, P = 0.003). There were 3 (9%) peri-procedural complications with no peri-procedural deaths.

CONCLUSION

Real-world data supports the efficacy and safety of CA as first-line therapy at the time of the first VT hospitalization, compared to the initial ICD implant and AAD therapy.

Sacubitril/valsartan effects on arrhythmias and left ventricular remodelling in heart failure: An observational study

AIMS

Conflicting results have been reported in the literature on the potential antiarrhythmic effect of sacubitril/valsartan in heart failure patients with reduced ejection fraction (HFrEF). The objectives of this study were: 1- to evaluate the long term effects of sacubitril/valsartan on arrhythmic burden in HFrEF patients; 2- to evaluate the correlation between the reduction of premature ventricular complexes during f-up and reverse remodelling.

METHODS

We identified 255 consecutive HFrEF patients treated with sacubitril/valsartan between March 2017 and May 2020 and followed by the Heart Failure and Cardiac Transplant Unit of IRCCS San Matteo Hospital in Pavia (Italy). Within this subgroup, 153 patients underwent 24 h-Holter-ECG or implantable cardioverter defibrillators (ICD) interrogation at baseline, at 12 months (t1) and at 24 months (t2) and transthoracic echocardiography at baseline and after 12 months after the beginning of sacubitril/valsartan. Cardiac-related hospitalizations were analyzed in the 12 months preceding and during 24 months following the drug starting date.

RESULTS

Global burden of 24-h premature ventricular complexes (PVC) was significantly reduced at 12 months (t1) and at 24 months (t2) as compared to the same period before treatment (1043 [304-3360] vs 768 [82-2784] at t1 vs 114 [9-333] at t2, P = 0.000). In the subgroup of patients implanted with biventricular ICD (n = 30), the percentage of biventricular pacing increased significantly (96% [94-99] vs 98% [96-99] at t1 vs 98%[97-100] at t2; P = 0.027). The burden of non-sustained ventricular tachycardia and sustained ventricular tachycardia did not change from baseline to t1 and t2, but a reduction of patients with at least one ICD appropriate shock was reported. The correlations between reduction in 24 h PVC and reduction in LV-ESVi or improvement in LVEF were not statistically significant (respectively R = 0.144, P = 0.197 and R = -0.190, P = 0.074). Heart failure related hospitalizations decreased during follow up (11.1% in the year before treatment vs 4.6% at t1 and 4.6% at t2; P = 0.040).

CONCLUSION

Sacubitril/valsartan reduced the number of premature ventricular complexes and increased the percentage of biventricular pacing in a cohort of HFrEF patients already on optimal medical therapy. PVC reduction did not correlate with reverse left ventricular remodelling. Whether sacubitril/valsartan has any direct antiarrhythmic effects is an issue to be better explored in future studies.

Efficiency of MVP ECG Risk Score for Prediction of Long-Term Atrial Fibrillation in Patients With ICD for Heart Failure With Reduced Ejection Fraction

BACKGROUND AND OBJECTIVES

The morphology-voltage-P-wave duration (MVP) electrocardiography (ECG) risk score is a newly defined scoring system that has recently been used for atrial fibrillation (AF) prediction. The aim of this study was to evaluate the ability of the MVP ECG risk score to predict AF in patients with an implantable cardioverter defibrillator (ICD) and heart failure with reduced ejection fraction in long-term follow-up.

METHODS

The study used a single-center, and retrospective design. The study included 328 patients who underwent ICD implantation in our hospital between January 2010 and April 2021, diagnosed with heart failure. The patients were divided into low, intermediate and high-risk categories according to the MVP ECG risk scores. The long-term development of atrial fibrillation was compared among these 3 groups.

RESULTS

The low-risk group included 191 patients, the intermediate-risk group 114 patients, and the high-risk group 23 patients. The long-term AF development rate was 12.0% in the low-risk group, 21.9% in the intermediate risk group, and 78.3% in the high-risk group. Patients in the high-risk group were found to have 5.2 times higher rates of long-term AF occurrence compared to low-risk group.

CONCLUSIONS

The MVP ECG risk score, which is an inexpensive, simple and easily accessible tool, was found to be a significant predictor of the development of AF in the long-term follow-up of patients with an ICD with heart failure with reduced ejection fraction. This risk score may be used to identify patients who require close follow-up for development and management of AF.

Early ganglion stellate blockade as part of two-step treatment algorithm suppresses electrical storm and need for intubation

BACKGROUND

For the treatment of patients with electrical storm (ES), we established a two-step algorithm comprising standard anti-arrhythmic measures and early ultrasound-guided stellate ganglion blockade (SGB). In this single-center study, we evaluated the short-term efficacy of the algorithm and tested the hypothesis that early SGB might prevent the need for intubations.

METHODS

Overall, we analyzed data for 70 ES events in 59 patients requiring SGB (mean age 67.7 ± 12.4 years, 80% males, left ventricular ejection fraction 30.0% ± 9.1%), all with implantable cardioverter-defibrillators (ICDs).

RESULTS

The mean time from ES onset to SGB was 13.2 ± 12.3 hours. Percentage and mean absolute reduction in shocks at 48 hours after SGB reached 86.8% (-6.3 shocks), and anti-tachycardiac pacing (ATP) declined by 65.9% (-51.1 ATPs; all P < 0.001). Patients with the highest sustained ventricular arrhythmia (VA) burden (shocks ≥10/48 h; ATPs 10-99/48 h and ≥100/48 h) experienced the highest percentage decrease in ICD therapy (shocks -99.1%; ATPs -92.1% and -100.0%, respectively). For clinical response by defined criteria and two outcome periods (1/no sustained VA ≤48 hours post SGB, and 2/no ICD shock or <3 ATPs/day from day 3 to discharge/catheter ablation/day 8), 75.7% and 76.1% experienced complete response, respectively. Catecholamine support, no/low-dose β-blocker therapy, polymorphic/mixed-type VA, and baseline sinus rhythm versus atrial fibrillation were more frequent in patients with early arrhythmia recurrence. Temporary Horner's syndrome occurred in 67.1%, and no other adverse events were recorded. Intubation and general anesthesia during and after SGB were not needed.

CONCLUSION

The presented two-step algorithm for treating ES proved efficacious and safe. The results support implementation of early SGB in routine ES management.

Contemporary management of ventricular arrhythmias in heart failure

Enhanced ventricular arrhythmogenesis is commonly experienced by patients in the end-stage of heart failure spectrum. A high burden of ventricular arrhythmias can affect the ventricular systolic function, lead to unexpected hospitalizations and further deteriorate the prognosis. Management of ventricular arrhythmias in this population is challenging. Implantable cardioverter-defibrillators are protective for the immediate termination of life-threatening arrhythmias but they have no impact in reducing the arrhythmic burden. Combination treatment with invasive (catheter ablation, mechanical hemodynamic support, sympathetic denervation) and noninvasive (antiarrhythmic drugs, medical therapy for heart failure, programming of implantable devices) therapies is commonly required. The aim of this review is to present the available therapeutic options, with main focus on recently published data for catheter ablation and provide a stepwise treatment approach.