Implantable Cardioverter-defibrillator Shocks Research Articles

The role of cardiac sympathetic denervation for ventricular arrhythmias: an updated systematic review and meta-analysis.

The role of the sympathetic nervous system in the initiation and continuation of ventricular tachyarrhythmias (VTA) is well established. However, whether CSD reduces implantable cardioverter-defibrillator (ICD) shocks and recurrent VTA is still uncertain. A comprehensive literature search was performed at Medline and Embase until March 2023. The primary outcome was the rate of ICD shocks and VTA per patient-year in our pooled analysis of all included articles. Analyses were conducted using Comprehensive Meta-Analysis software. Initial search yielded 1324 scientific studies with a total of 15 studies fitting our inclusion criteria. ICD shocks at 1 year post-CSD revealed an event rate of 69.8% (95% CI, 56.4-80.4% with 50% heterogeneity) (I2 statistic). ICD shocks at 6 months had an event rate of 59.1% (95% CI, 46.9-70.4%; 47 I2). Analysis of our pooled studies showed that 64.3% of individuals achieved freedom from VTA at 1 year post-CSD (95% CI, 42.3-81.5%; 26% I2), while 62.3% were free from recurrent VTA 6 months post-CSD (95% CI, 51.2-72.2%; 40% I2). Time to mortality directly caused by recurrent VTA post-CSD was subdivided into short-term (0-30 days), intermediate-term (31-364 days), and long-term (≥ 365). Mortality for the short-term tertile was 8.9% (95% CI, 5.0-15.4%; 0% I2), medium-term was 5.3% (95% CI, 2.4-11.3%; 0% I2), and long-term 5.2% (95% CI, 2.4-10.9%; 0% I2). CSD seems to be promising as an acceptable treatment strategy for recurrent VTA refractory to traditional pharmacological or ablation therapy.

Development of an Innovative Decision-Aid to Better Align Patients' Implantable Cardioverter Defibrillator Shock Status With Goals of Care.

Development of an Innovative Decision-Aid to Better Align Patients' Implantable Cardioverter Defibrillator Shock Status With Goals of Care.

Mitral valve prolapse in sudden cardiac arrest survivors: Coincidence or causal relationship?

Sudden cardiac arrest (SCA) risk stratification in patients with mitral valve prolapse (MVP) may be complicated by other potential causes of arrhythmia. We aimed to characterize SCA survivors with isolated MVP (iMVP) and non-isolated MVP (non-iMVP) and to assess their long-term follow-up. This ambispective study included 75 patients with MVP who experienced SCA and were treated in our center between 2009 and 2024. They were divided into 3 groups according to probability of relation between SCA and comorbidities. The control group comprised 112 participants with MVP but without a history of SCA. We analyzed all available electrocardiograms, Holter electrocardiography monitoring, and echocardiograms, including longitudinal strain. A novel parameter, the systolic atrial-directed notch (SADN), was tested. SCA survivors with iMVP (n = 28) had higher prevalence of mitral annular disjunction (80% vs 35.7%; P = .006), Pickelhaube sign (60% vs 8.3%; P = .008), and SADN >2 mm (69.6% vs 14.3%; P = .001) as well as higher absolute longitudinal strain values in basal and mid segments of the inferior and inferolateral wall than patients with SCA and non-iMVP without other defined structural heart diseases (n = 14). The differences were also observed in comparison to the control group. The cumulative incidence of appropriate implantable cardioverter-defibrillator shocks within 6 years was 62% in patients with iMVP and 23% in the group with non-iMVP without other defined structural heart diseases. Echocardiographic findings such as mitral annular disjunction, SADN, Pickelhaube sign, and increased segmental strain may be useful in the assessment of the relation between SCA and MVP. Malignant arrhythmias often recur in SCA survivors with iMVP.

The impact of shock therapy on depression development and remote prognosis in cardiac resynchronization therapy recipients.

The aim of this study was to assess the incidence and clinical significance of depression in patients with cardiac resynchronization therapy with an implantable cardioverter-defibrillator (CRT-D). The study was also to evaluate the impact of shock therapy on depression development and long-term prognosis. The prospective study encompassed 396 consecutive heart failure (HF) patients implanted with CRT-D. All patients completed the Beck Depression Inventory (BDI-II) and underwent a psychiatric examination at baseline. 221 patients free of depressive symptoms at baseline were included into the final analysis. The assessment of psychiatric status was routinely repeated every 6 months as well as after the shock delivery. The primary outcome was a composite endpoint of death or hospitalization for HF. During long-term observation (median 37.1 months) 52 (23.5%) patients suffered from an implantable cardioverter-defibrillator (ICD) shock, whereas 48 (21.8%) subjects developed depression. The incidence of new-onset depression was significantly higher in patients after shock delivery (Shock Group), CRT non-responders and subjects with atrial fibrillation. The risk for a composite endpoint was higher in the Shock Group than subjects without an ICD intervention: 57.7% vs. 25.4% and in patients with new-onset depression compared to the population free of this disorder: 62.5% vs. 24.9% (all p < 0.001). New-onset depression (HR 1.7) and an ICD shock (HR 2.1) were strong independent predictors of poor prognosis. Depression is a common mental disorder in CRT-D recipients, that adversely affects long-term prognosis. Subjects suffering from ICD shocks and those with HF progression are at higher risk of experiencing depressive symptoms.

Atrial Tachyarrhythmias With Ultra-Rapid Ventricular Response and Sudden Death in Patients Without Structural Heart Disease.

Sudden cardiac death (SCD) is generally associated with life-threatening ventricular arrhythmias. Supraventricular arrhythmias are an accepted cause of SCD in Wolff-Parkinson-White syndrome and complex congenital heart disease. However, the role of atrial tachyarrhythmias (ATAs) in SCD in patients with structurally normal hearts is unclear. The goal of this study was to present data on resuscitated patients without structural heart disease (SHD), experiencing recurrent implantable cardioverter-defibrillator (ICD) shocks, who share common clinical and electrical features suggesting that ATAs can cause SCD. We describe the clinical characteristics and ICD analysis of syncopal events terminated with shock delivery in 5 young SCD survivors without SHD. Details on the follow-up after ablation of the arrhythmia causing the syncopal episode are also reported. In all patients (4 male, 1 female; median age 23 years; age range 15-47 years), a surface electrocardiogram recording in the resuscitation setting suggested ventricular fibrillation. After the index event, all patients exhibited recurrent arrhythmic syncopal episodes in a setting of elevated adrenergic tone, treated with ICD shocks. ICD interrogation suggested ATAs (atrial fibrillation in 4 patients, atrial tachycardia in 1 patient), conducting to the ventricles at rates approaching 300 beats/min, as the underlying arrhythmia leading to the syncopal events. ATA ablation abolished episodes of arrhythmic syncope and shock delivery in all patients after a median follow-up of 34months. No patient died suddenly during follow-up. Common clinical and electrical features define a distinct entity of SCD caused by ATAs with ultra-rapid ventricular response in otherwise healthy patients. Catheter ablation of the ATA is an effective treatment in these patients.

Determining the Relationship Between Sleep Problems, Shock Pain, and Shock Anxiety in Patients With ICD.

This study aimed to determine the relationship between sleep problems, shock pain, and shock anxiety in patients with implantable cardioverter defibrillator (ICD) and the affecting factors. The population of this descriptive cross-sectional study consisted of all patients who underwent ICD implantation in university hospital (N = 200), and the sample consisted of patients who met the inclusion criteria of the study (n = 132). Data were obtained using a "General Information Form", the "Florida Shock Anxiety Scale (FSAS)", the "Epworth Sleepiness Scale (ESS)", the "Pittsburgh Sleep Quality Index (PSQI)", and the "Visual Pain Scale (VPS)". The mean age of the patients was 66.13 years. The VPS was 6.40±3.36; the mean FSAS score was 29.98±8.46; the mean PSQI score was 8.02±3.81; the mean ESS score was 7.59±4.10. PSQI had a statistically significant correlation with the total FSAS score (p<0.001) and a statistically insignificant correlation with ESS (p>0.001). Age, sex, marital status, smoking status, cohabitants, previous ICD shocks, the status of lying on ICD, and fear of dislocation of ICD affected the total FSAS score; sex, employment status, history of heart attack, defined sleep disorder, awakening from sleep due to nightmares, and cessation of breathing during sleep affected the total PSQI score; history of previously defined sleep disorder, history of heart attack, use of medication for a sleep disorder, the pain felt when lying on ICD, and pain experienced during ICD shocks affected the total ESS score. The mean shock VPS scores differed between patients who received an ICD shock during sleep and those who were awakened by nightmares. It was found that the shock anxiety and shock pain scores of ICD patients were above average, that they had poor sleep quality, and that their sleepiness was at the level of "normal but increased daytime sleepiness".

Abstract 4137113: The Effectiveness of Cardiac Resynchronization Therapy in Patients with Cardiac Sarcoidosis: A Retrospective Analysis

Background: Cardiac sarcoidosis (CS) manifests in a wide range of clinical presentations, including conduction system abnormalities, ventricular arrhythmias, and systolic heart failure. Although cardiac resynchronization therapy (CRT) has shown efficacy in treating select nonischemic cardiomyopathy patients, its specific impact on CS patients remains less explored. This study aimed to evaluate the outcomes of CRT therapy in CS patients, focusing on implantable cardioverter defibrillator (ICD) therapies, heart failure (HF) hospitalizations and mortality. Methods: We retrospectively reviewed all patients with a clinical or histological diagnosis of CS who underwent device implantation (ICD or Permanent Pacemaker (PPM)) with or without CRT therapy at Johns Hopkins Hospital between 2004 and 2024. Baseline characteristics and echocardiographic parameters were assessed. Heart failure hospitalizations, the frequency of ATP (Anti-Tachycardia Pacing) or ICD shocks, and all-cause mortality were also evaluated as the outcomes. Results: The study included 212 patients (40.1% female, average age 52.8 ± 11.1 years). Eighty-five patients underwent CRT implantation (82 CRT-D and 3 CRT-P), whereas the rest received either an ICD or a PPM without CRT therapy. Most CRT devices (58.82%) were upgrades from an initial PPM or ICD. Over a follow-up of 6.15 ± 4.43 years, 27 (12.74%) patients were hospitalized for heart failure (HF), 86 (40.56%) experienced ATP or ICD shocks, and 17 (8.02%) died. The composite outcome was observed in 103 patients (48.5%), with no significant differences between CRT and non-CRT groups ( P = .51). Survival analysis indicated significantly reduced freedom from HF hospitalizations in the CRT group compared to non-CRT group ( P = .01). However, ATP/ICD shocks did not have a significant difference. CRT recipients showed an improvement in left ventricular ejection fraction (LVEF) from 35.3 ± 12.6% to 38.9 ± 13.6% at 6 months ( P = .01). Non-recipients showed no significant change in LVEF ( P = .43). Conclusions: Over an average six-year follow-up period, CRT upgrade does not appear to affect ATP/ICD shock and mortality in CS patients, although it is associated with significantly higher rates of heart failure (HF) hospitalizations compared to CS patients with an ICD or PPM alone. These findings underscore the complex response of CS patients to CRT, highlighting the need for further research to optimize treatment strategies within this subgroup.

Abstract 4121624: Ambulatory Inotropic Support in Patients with Stage D Heart Failure Does Not Increase ICD Therapies

Background: Ambulatory inotropic infusions can be used as a palliative therapy (PT) or bridge to advanced therapies in end-stage heart failure (ESHF) patients, many of whom have implantable cardioverter defibrillators (ICDs). Research Questions: How often do patients receive ICD therapies after initiation of outpatient inotropic support and how often is defibrillation inactivated? Methods: We conducted a retrospective review of all patients discharged from an academic tertiary medical center with a new prescription for inotropic therapy between November 2017 and March 2023. Clinical data, Palliative Care consultation, and ICD interrogations before and after inotrope initiation were extracted from the electronic health record. Results: The cohort comprised 45 patients discharged on new inotropic support, including 22 (49%) with intent of PT and 23 (51%) as a bridge to advanced therapies (Figure). Among PT patients, 15 (68%) had an ICD in place with only 4 having ICD therapies deactivated at discharge. Only 2 additional PT patients had a documented discussion regarding ongoing ICD therapies. By 1 year, 4 (18%) PT patients were transitioned to hospice and 13 (59%) had died, with only 1 additional patient having ICD deactivation. Of 28 patients discharged on inotropic infusions with ICD therapies on (both PT and bridge patients), only 4 patients had ICD therapies turned off later and no ICD shocks were reported for the year following initiation of inotropic support. Conclusion: In a series of 45 patients initiated on inotropic support for PT or bridge to advanced therapies, the majority (77%) had an active ICD, but therapies were rarely delivered. Notably, there were very few documented discussions regarding ICD therapies in PT patients even with specialty Palliative Care consultation. In patients with ESHF initiated on inotropic support as PT, most patients chose to leave ICD therapies in place. For those patients, there was a low rate of ICD therapies delivered.

Abstract 4135194: Safety and Efficacy of Mechanical Circulatory Support during VT ablation

Introduction: Ventricular arrythmias are prevalent in patients with advanced heart failure and associated with increased mortality. Outcomes of electrophysiology ablation on patients requiring mechanical circulatory support (MCS) are not well described. We aimed to analyze the safety and efficacy of ventricular tachycardia (VT) ablation in patients requiring MCS at the Emory system. Methods: Patients were identified via retrospective chart review from October 2022 through August 2023. Patients who underwent VT ablation with the support of Impella, left ventricular assist device (LVAD), intra-aortic balloon pump (IABP), and venoarterial extra-corpeal membrane oxygenation (VA ECMO), or any combination of these were included. Results: A total of 7 patients of average age 56 ± 10 years, predominantly male (85.7%), with cardiomyopathy of mean EF 18.6% +/- 8.5 (ischemic 71.4%) underwent MCS supported VT ablation. One patient had 2 separate VT ablation procedures for refractory VT. Of these 8 procedures, 4 utilized a single type of MCS (2 impella, 2 LVAD) while 4 used a second type of MCS in combination with an Impella (2 impella RP, 1 VA ECMO, 1 IABP). Success at time of ablation was present in 75% of cases. Average time of outpatient follow up was 82 ± 31 days. At time of follow up, 50% of patients remained free of VT or with a single VT episode not requiring implantable cardioverter-defibrillator (ICD) shock. One patient had gone on to undergo successful heart transplantation. Procedural complications were noted in one patient, who suffered cardioembolic cerebrovascular accident (CVA) 2 days post-op. Transthoracic echo (TTE) 5 days post-op revealed LV mural thrombus as likely etiology of CVA. Conclusion: While there are no clear guidelines directing the use of MCS during VT ablation, our single academic institution experience suggests safety and feasibility of its use to support select, high risk cases.

Abstract 4148089: Comparative Efficacy of Carvedilol versus Metoprolol in Patients with Implantable Cardioverter Defibrillators and Ventricular Arrhythmias: A Systematic Review and Meta-Analysis

Background: Ventricular arrhythmias are major causes of morbidity and mortality in patients with cardiovascular disease. Implantable cardioverter-defibrillators (ICDs) are commonly used to prevent sudden cardiac death in these patients. However, patients with ICDs frequently experience recurrent arrhythmias and inappropriate shocks, which can impact their quality of life. Beta-blockers, specifically carvedilol and metoprolol, are commonly prescribed to manage these arrhythmias. This meta-analysis aims to compare the impact of both medications in this patient population. Methods: A comprehensive literature search was conducted to identify relevant studies comparing carvedilol to metoprolol in patients with ventricular arrhythmias or ICDs. Study outcomes included all-cause mortality, recurrent ventricular arrhythmia, and inappropriate ICD shocks. Effect estimates are presented as hazard ratios (HR) with 95% confidence intervals (CI). Results: 1,453 studies were identified through database search. After full-text screening, a total of 5 studies involving 9,292 patients were included. We found no significant difference in the incidence of recurrent ventricular arrhythmias between carvedilol and metoprolol (HR = 0.99, 95% CI [0.75, 1.32], P = 0.97). Additionally, Carvedilol showed a trend toward reduction of all-cause mortality (HR = 0.83, 95% CI [0.68, 1.03], P = 0.09). On the other hand, Carvedilol was associated with a statistically significant reduction of inappropriate ICD shocks (HR = 0.61, 95% CI [0.48, 0.78], P &lt; 0.001). Conclusion: Carvedilol may offer additional benefits over metoprolol in managing patients with ventricular arrhythmias or ICDs, particularly in minimizing the incidence of inappropriate ICD shocks. However, no significant difference was found in terms of all-cause mortality and recurrent ventricular arrhythmia incidence. Further research is needed to confirm these findings and guide clinical decision-making.

Asthma and the risk of cardiac events among patients with long qt syndrome after age 40

BackgroundLimited data exist on the impact of asthma on long QT syndrome (LQTS) in middle-aged and older adults. ObjectiveThis study aimed to examine the association between asthma, β2-agonist treatment, and cardiac events (CEs) in LQTS patients over 40 years of age. MethodsThe risk of CEs (comprising syncope, aborted cardiac arrest, implantable cardioverter-defibrillator shock, or sudden cardiac death) from age 40 through 75 years, by the presence of asthma with and without treatment with a β2-agonist inhaler, was assessed among 1020 LQTS patients from the Rochester LQTS Registry. ResultsAmong 1020 LQTS patients, 162 (16%) had asthma by age 40 years or subsequent follow-up, with 63% treated with a β2-agonist inhaler. Patients with asthma vs no asthma had a higher cumulative rate of CEs from age 40 through 75 years (44% vs 26%, P < .001). Consistently, multivariate analysis showed that asthma was associated with a 2-fold (hazard ratio 1.97, P = .001) increased risk of CEs. Subgroup analysis showed that the association of asthma with CEs was consistent within risk subsets of LQTS patients, including QTc duration, syncope prior to age 40 years, β-blocker use, sex, and LQTS genotype (all P values for risk subset-by-asthma interaction >.10). Asthma patients with LQTS who were treated with a β2-agonist inhaler did not show an increased risk compared with those who were not treated (hazard ratio 1.02, P = .963). ConclusionThe presence of asthma is associated with increased risk of CEs among middle-aged and older patients with LQTS regardless of baseline risk factors or treatment with a β2-agonist inhaler.

The discontinuation of implantable cardioverter defibrillator shock therapies towards the end of life: consensus guideline from the British Heart Rhythm Society.

Implantable cardioverter defibrillators (ICDs) are implanted in increasing numbers of patients with the aim of treating ventricular arrhythmias in high-risk patients and reducing their risk of dying. Individuals are also living longer with these devices. As a result, a greater number of patients with an ICD will deteriorate either with worsening cardiac failure, another non-cardiac condition or general frailty and will have a limited prognosis. Frequently, they will be cared for by non-cardiac teams who may be less familiar with ICDs. Therefore, to ensure the person receives high-quality end-of-life care, they should have the opportunity to consider and discuss the option to deactivate the shock function of their ICD. If the ICD shock therapy is not discontinued, there is an increased risk that, as a person reaches the last days of life, the ICD may deliver multiple, painful shocks that are distressing. There is also a risk that the device may delay the person's natural death, which the person would not have chosen if they had been given the opportunity to discuss discontinuation. The British Heart Rhythm Society has developed a practical guideline to support all healthcare professionals who are caring for patients who have an ICD. This includes descriptions of different device types, ethical and legal aspects, timing and nature of ICD discussions and practical advice regarding how the devices may be deactivated. It aims to promote awareness and timely discussion between professionals and patients and to encourage best practice.

Quality of Life in Subcutaneous or Transvenous Implantable Cardioverter-Defibrillator Patients: A Secondary Analysis of the PRAETORIAN Trial.

The subcutaneous implantable cardioverter-defibrillator (S-ICD) was developed to overcome the risk of lead-related complications associated with the transvenous implantable cardioverter-defibrillator (TV-ICD). In contrast to the TV-ICD, the S-ICD is a completely extrathoracic device. Subsequently, complications differ between these 2 implantable cardioverter-defibrillators, which might impact patient perceptions of the therapies. This prespecified secondary analysis of the PRAETORIAN trial evaluates differences in quality of life. The PRAETORIAN trial (A Prospective, Randomized Comparison of Subcutaneous and Transvenous Implantable Cardioverter Defibrillator Therapy) randomized patients with an implantable cardioverter-defibrillator indication, without the need for pacing to S-ICD or TV-ICD therapy. Two questionnaires were collected at baseline, discharge, 12 months, and 30 months. The Duke Activity Status Index measures cardiac-specific physical functioning, and the 36-Item Short Form Health Survey measures physical and mental well-being, with the subscales bodily pain and mental health being of interest in this analysis. Mann-Whitney U tests were used to compare study arms, and a mixed model was used to describe the questionnaire outcomes over time. Patients were randomized to S-ICD (n=426) and TV-ICD (n=423). In the S-ICD group, 20% were women versus 19% in the TV-ICD group. The median age was 63 (interquartile range, 54-69) years in the S-ICD group versus 64 (interquartile range, 56-69) years in the TV-ICD group. There were no significant differences in the Duke Activity Status Index and 36-Item Short Form Health Survey subscales for bodily pain and mental health between the groups at any time point. Patients with a shock in the last 90 days had significantly lower scores for social functioning (P=0.008) and role limitations due to emotional problems (P=0.001) than patients without a shock, but this effect did not differ between treatment arms. In a large randomized cohort of patients with an S-ICD or TV-ICD, no difference in overall quality of life was observed. However, implantable cardioverter-defibrillator shocks resulted in a reduction in quality of life, regardless of the device type or appropriateness. URL: https://www.clinicaltrials.gov; Unique identifier: NCT01296022.

Drug therapy and catheter ablation for management of arrhythmias in continuous flow left ventricular assist device's patients: a Clinical Consensus Statement of the European Heart Rhythm Association and the Heart Failure Association of the ESC.

Left ventricular assist devices (LVADs) are an increasingly used strategy for the management of patients with advanced heart failure. Although these devices effectively improve survival, atrial and ventricular arrhythmias are common with a prevalence of 20-50% at one year after LVAD implantation. Arrhythmias predispose these patients to additional risk and are associated with considerable morbidity from recurrent implantable cardioverter-defibrillator shocks, progressive failure of the unsupported right ventricle, and herald an increased risk of mortality. Management of patients with arrhythmias and LVAD differs in many aspects from the general population heart failure patients. These include ruling out the reversible causes of arrhythmias that in LVAD patients may include mechanical irritation from the inflow cannula and suction events. For patients with symptomatic arrhythmias refractory to medical treatment, catheter ablation might be relevant. There are specific technical and procedural challenges perceived to be unique to LVAD-related ventricular tachycardia (VT) ablation such as vascular and LV access, signal filtering, catheter manoeuvrability within decompressed chambers, and electroanatomic mapping system interference. In some patients, the arrhythmogenic substrate might not be readily accessible by catheter ablation after LVAD implantation. In this regard, the peri-implantation period offers a unique opportunity to surgically address arrhythmogenic substrate and suppress future VT recurrences. This document aims to address specific aspects of the management of arrhythmias in LVAD patients focusing on anti-arrhythmic drug therapy and ablations.

Defibrillator shocks and their effect on objective asian patient outcomes: results of the painfree SST clinical trial

Abstract Background The implantable cardioverter defibrillator (ICD) reduces mortality in patients at risk of sudden cardiac death. However, the effect of ICD shock on device-measured activity is unknown. The aim of this analysis was to analyze the acute and long-term effects of ICD shock on objective behavioral data. Methods The PainFree SST study was a prospective, multicenter, global study that enrolled 2770 patients including 225 from from Asia (181 from Japan, 25 from India, and 19 from Malaysia). Patient physical activity was determined from the device built-in accelerometer. The device translates the accelerometer output into a count of active minutes, which is stored as a daily total value in device memory for a rolling window of 425 days. Obviously, activity is measured only after device implantation. Early after implant, activity is reduced due to the procedure and thus not representative. Therefore, no baseline can be reported for activity. The follow-up activity data was analyzed with a linear mixed model, with a random effect for patient and an auto-regressive correlation matrix for subsequent measurements of individual patients. Results Figure 1 shows average daily activity between 90 days before and 90 days after a shock. The dashed vertical line indicates the day of shock. Both patients from Asia and from other countries show a drop in activity after a shock with recovery in the subsequent 30-60 days. The curve for Asian patients is more variable than the curve for other countries due to the lower number of patients (there were 33 Asian patients with shocks contributing data). Figure 2 shows average daily activity before and after ATP therapy. Any post shock measurement is excluded. Contrary to the temporary reduction in activity around a shock (Figure 1), ATP therapies do not seem to have an impact on activity. In patients from the other countries, activity is significantly reduced when patients are hospitalized (-66.3 minutes/day, p&amp;lt;0.0001), but not in Asian patients (-5.1 minutes/day, p=0.71). Both in Asian and other countries, activity is significantly reduced after an ICD shock (Asian: -47.5 minutes/day, p=0.0002; Other countries: -21.5 minutes/day, p&amp;lt;0.0001). The effect of shock for Asian is greater than the other countries (p=0.054). In the month after the shock there is a significant recovery, +34.8 minutes/day in Asian patients (p=0.0077) and +7.7 minutes/day in patients from other countries (p=0.031). The recovery is trended to be bigger in Asian patients (p=0.058). Conclusions ICD shocks have a lasting adverse impact on objective, device-measured physical activity, particularly among Asian individuals. Successful management of patients with an ICD necessitates specific attention to clinically relevant behavioral outcomes, aiming to expedite recovery and facilitate a return to activities of daily living, with a particular focus on the Asian population.

Targeting ventricular tachycardia originating from the anterolateral papillary muscle with stereotactic body radioablation therapy

Abstract Background Ventricular Tachycardia (VT) is prevalent in the setting of non-ischaemic cardiomyopathy (NICM), a heterogeneous group of conditions characterized by myocardial dysfunction in the absence of coronary artery disease. Challenges of catheter ablation to treat VT in NICM patients are well known, and recurrence rates can be as high as 58%. Stereotactic body radioablation therapy (SBRT) involves precise delivery of radiation to arrhythmogenic substrates, and represents a novel treatment to reduce recurrent implantable cardioverter defibrillator (ICD) therapies in patients with refractory VT. Though SBRT has shown preliminary effectiveness in reducing VT episodes, its effectiveness in NICM patients has not been widely evaluated. Purpose To evaluate SBRT effectiveness in NICM patients with scars at the basal anterolateral papillary muscle at a tertiary care center between November-December 2022. Methods Eligible patients had their VT substrate mapped using a single-use ECGI vest and a 4D-CT simulation scan. In addition, MRI scans were used to aid anatomical identification of the anterolateral papillary muscle which could not be seen on the non-contrast diagnostic CTs. SBRT was delivered in a single fraction of 25 Gy under image guidance. Effectiveness of the treatment was evaluated as changes in frequencies of total antitachycardia pacing (ATP) and ICD shock episodes from 6 months pre-, and within to 3, 6, and 12 months follow up post SBRT. Results Participants were 3 males with NICM, aged 56, 60, and 73 with previous dual chamber ICD implantation, 2 of whom had a history of VT ablation/ VT storm and paroxysmal atrial fibrillation. All participants had basal lateral scar, and were receiving beta blockers, mexiletine, and amiodarone with refractory VT before SBRT treatment. Prior to SBRT, ICD device interrogation showed a total of 119 (77, 7, and 35 in patients 1-3 respectively) ATPs, and 27 (10, 1, and 16 in patients 1-3 respectively) ICD shocks delivered. At 12 month follow-up, none of the participants experienced any episodes of ATP or ICD shock. Ejection fraction remained consistent pre-post SBRT. Conclusion SBRT showed remarkable success in reducing ATP and ICD shock episodes, facilitating uncomplicated 1 year follow-up in 3 male patients with NICM and VT from the anterolateral papillary muscle.

Risk stratification for a primary prevention ICD: Performance of the MADIT-ICD Benefit Score in contemporary real world patients

Abstract Background We have recently developed the MADIT-ICD Benefit Score to improve risk stratification for primary implantable cardioverter defibrillator (ICD) implantation by assessing the competing risk of life-threatening ventricular tachyarrhythmia (VTA) vs. non-arrhythmic mortality based using simple clinical variables. Patients with a MADIT-ICD Benefit Score of &amp;lt; 50 are more likely to experience non-arrhythmic mortality than life-threatening VTA, and therefore derive limited benefit from a prophylactic ICD. Purpose We aimed to provide data on the performance of the MADIT-ICD Benefit Score in a real world population, comprising patients with HFrEF and either ischemic or nonischemic cardiomyopathy (ICM/NICM) who are treated with contemporary guideline-directed medical therapy (GDMT). Methods The study population comprised 2875 patients who were implanted with a primary prevention ICD and prospectively followed in a large tertiary healthcare system (the University of Rochester Medical Center, including 3 affiliated hospitals in Upstate New York) between 2017 through 2023. Arrhythmic events were captured from device interrogation data, which were blindly adjudicated by 2 electrophysiologists. Results Among the 2875 study patients, mean age was 62 ± 15 years, 1265 (44%) were women, and 1667 (58%) had ICM. Guideline-directed medical therapies, including angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, angiotensin receptor/neprilysin inhibitors, beta-blockers, mineralocorticoid receptor antagonists, and sodium-glucose transport protein 2 (SGLT2) inhibitors, were prescribed to 43%, 36%, 96%, 67% and 32% of study patients, respectively. The 2-year cumulative incidence of VTA, after accounting for the competing risk of death, was 19% vs. 11% in patients with a Score of ≥50 vs. &amp;lt;50, respectively (p&amp;lt;0.001; Figure 1A). Findings regarding ICD shocks were consistent (8% vs. 4%, respectively, p&amp;lt;0.001; Figure 1B) The rate of VTA events at 4 years was directly correlated with increasing quartiles of the MADIT-ICD Benefit Score, while the corresponding rates of non-arrhythmic mortality were inversely correlated with score quartiles (Figure 1C). A similar direct correlation with increasing Benefit Score quartiles was observed when the endpoint of ICD shocks was assessed (Figure 1D). Accordingly, the benefit of the ICD (calculated as the difference between predicted rates of VTA/shock events and corresponding rates of non-arrhythmic mortality) was attenuated with decreasing quartiles of the MADIT-ICD Benefit Score (Figures 1C and 1D; right column). Conclusions We show good performance of the MADIT-ICD Benefit Score in a large cohort of real world ICD recipients who are treated with contemporary GDMT. These data support the use of the MADIT-ICD Benefit Score for improved risk stratification and for shared decision-making in contemporary candidates for a primary prevention ICD.

Novel electric predictors of lethal arrhythmic event in patients with hypertrophic cardiomyopathy

Abstract Background Little is known regarding the association between electrical markers and lethal arrhythmic events (LAE) in patients with hypertrophic cardiomyopathy (HCM). This study aimed to identify the electrical predictors of LAE in adult patients with HCM. Methods This study was a retrospective analysis of patients with HCM at a single center from 1998 to 2021. LAE was defined as a composite outcome of (1) sustained ventricular arrhythmia, (2) aborted sudden cardiac death (SCD), (3) implantable cardioverter defibrillator (ICD) implantation, and (4) appropriate ICD shock. A 12-lead electrocardiography was performed at the time of diagnosis. Results A total of 611 patients with HCM were analyzed, and 48 (7.8%) experienced LAE. Patients who experienced LAE were diagnosed at a younger age and more frequently had history of ventricular arrhythmia, new-onset atrial fibrillation (AF) or non-sustained ventricular tachycardia. New-onset AF, an increase in the QTc interval, and the absence of massive LVH were associated with LAE risk. In addition to conventional markers of HCM Risk-SCD, consideration of the QTc interval and massive LVH on electrocardiography improved the prediction of LAE (area under curve 0.682 to 0.740). Further inclusion of new-onset AF, history of ventricular arrhythmia, HCM type, and left ventricular mass index improved the predictability to 0.867. Conclusion An increase in the QTc interval, the absence of a massive LVH pattern on electrocardiography (ECG), and new-onset AF were independently associated with an increased risk of LAE. Comprehensive stratification using electrical markers improves the prediction of LAE when combined with conventional markers.

Outcomes and complications of transvenous implantable cardioverter defibrillator systems in the pediatric population: a systematic review and meta-analysis

Abstract Background Implantable cardioverter defibrillators (ICDs) are an important therapy for prevention of sudden cardiac death (SCD). Data on transvenous (TV) ICD therapy rates, complications, and system survival in children ≤ 21 years is limited by absolute numbers and inclusion of adults with congenital heart disease. Purpose To determine ICD therapy rates and complications in pediatric patients ≤ 21 years of age. Methods A systematic review and meta-analysis were conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Medline, Embase, PubMed Ahead-of-Print and in-process records, and Cochrane Database of Systematic Reviews were searched for full-text articles on pediatric ICD. Articles were assessed for inclusion by two authors via a consensus process; the exclusion criteria included: case reports, review articles, abstracts, editorials, articles not in English, articles solely on epicardial or subcutaneous leads, articles on unrelated topics, articles with &amp;lt;50% ICD leads, and articles with any patients &amp;gt;21 years old. Data were extracted by 1 author and verified by a 2nd author. Meta-analysis of aggregate data was performed, where possible. Random effects models were used for pooled inferences. All reported rates are annualized rates based on reported follow-up times in each study. Results Of 1325 articles, 23 met all inclusion and no exclusion criteria (Figure) representing 1700 patients implanted from 1987-2020. The average age of patients was 12.8 years (95% confidence interval [CI]: 11.9 – 13.7) with weight of 51.1 kg (95% CI: 42.2 – 60.0) (Table). Primary prevention was the indication in 56.4 % (95% CI: 45.0% – 67.7%). Only 14.8% (95% CI: 10.6% – 19.0%) of the patients had congenital heart disease while 22.6% (95% CI: 15.8% – 29.3%) had long QT syndrome. The annualized rate of appropriate shock was 7.0% (95% CI: 5.6% – 8.8%) and the rate of inappropriate shock was 4.8% (95% CI: 3.8% – 6.0%). Annualized rates of reported adverse events included lead failure: 2.3% (95% CI: 1.6% – 3.3%) and infection: 0.8% (95% CI: 0.4% – 1.6%), which could have led to system revision: 4.4% (95% CI: 2.1% – 9.4%). The all-cause mortality rate was 0.8% (95% CI: 0.6% – 1.2%) across 17 studies. In 9 studies with 719 patients, the heart transplant rate was 1.6% (95% CI: 0.6% – 3.9%). Conclusion In this first systematic review and meta-analysis of ICDs in pediatric patients, ICD therapy was effective for prevention of SCD with a 7.0% annualized rate of appropriate ICD shocks. This is comparable to the annualized rate of appropriate ICD shock for secondary prevention of SCD in adult randomized controlled trials. Most common adverse events in the pediatric population were lead failure and system revision. Further refinements in patient selection criteria for implantation and improvements in lead and device technology are needed for pediatric patients.FigureTable

High-intensity exercise-related sudden cardiac death in hypertrophy cardiomyopathy

Abstract Background Whether exercise provokes sudden cardiac death (SCD) in patients with hypertrophic cardiomyopathy (HCM) is uncertain. Current European guidelines recommend against high-intensity exercise in individuals with high SCD risk or obstructive physiology. Purpose We investigated the factors associated with exercise-related SCD in HCM. Methods We retrospectively analyzed of 2,844 consecutive patients with HCM who underwent evaluation between 2005 and 2023 at a high-volume tertiary center. SCD events were defined as a composite of aborted SCD, appropriate implantable cardioverter-defibrillator (ICD) shock, and SCD. Among 80 first SCD events (2.8%), 75 events had a description of the physical activity at the time of the event. Patients were classified into two groups according to physical activity level at the time of the SCD event. Group 1 included patients with high-intensity exercise-related SCD events, defined as happening during or immediately after high-intensity exercise or physical activity, while Group 2 included patients with SCD events happening at rest or during light or moderate physical activity. Results The 75 first SCD events included 44 aborted SCD, 22 appropriate ICD shocks, and 9 SCD. Median age at SCD event was 54 (IQR 39.5–62.5) years and 60 (80%) were men. Patients in Group 1 (n=14) were younger than patients in Group 2 (n=61) (23.5 [IQR 16–48] vs. 55 [IQR 44–64] years, p&amp;lt;0.001), and most patients in group 1 (92.9%) were under the age of 60 years. Patients in Group 1 had slightly smaller left ventricular (LV) end-diastolic dimension and had higher ESC SCD risk scores (3.6 [IQR 2.5–6.7] vs. 2.4 [IQR 1.7–4.8], p=0.044) than patients in Group 2; however, there were no significant differences in the proportion of high-risk patients (28.6% vs. 14.8%, p=0.396) or patients with AHA major SCD risk factors (57.1% vs. 55.7%, p=0.999). Otherwise, there were no significant differences in the presence of obstructive physiology, apical HCM, and apical aneurysm, LV systolic and diastolic function, and comorbidities between the two groups. Furthermore, of the 29 patients who underwent genetic testing, there was no difference in the proportion of patients with pathogenic sarcomeric variants according to exercise-related SCD (50.0% vs. 65.2%, p=0.683). To note, there was a non-significant tendency towards higher proportion of thin filament variants in Group 1 than Group 2 among those with pathogenic sarcomeric variants (100% [3/3] vs 26.7% [4/15], p=0.084). Conclusions Most high-intensity exercise-related SCD events happened under the age of 60. The ESC SCD risk score was higher in patients with high-intensity exercise-related SCD events, although the SCD risk categories or AHA risk factors could not discriminate patients at higher risk of events. These results suggest that exercise recommendations should not be based on SCD risk category, presence of obstruction, or degree of LV hypertrophy.