Implantable Cardioverter-defibrillator Group Research Articles

Similar incidence of ICD-shocks in diabetic compared to non-diabetic patients receiving implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D)

Abstract Background and aims Recent studies have suggested that diabetes patients with implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy-defibrillator (CRT-D) may experience a reduced incidence of appropriate ICD-shocks and an increased mortality rate. This study aims to assess whether there is parity in ATP-treatment and ICD-shocks between patients with and without type 2 diabetes mellitus (T2DM), and to analyze associated mortality rates. Methods Using the Danish pacemaker and ICD registry we included patients who received a first-time ICD or CRT-D implantation with a primary or secondary prophylactic indication, between January 1st 2000 to December 31st 2018. Outcomes were analyzed individually for each outcome. Cause specific Cox was used for i) appropriate ATP therapy or ICD-shock, ii) inappropriate ATP therapy or ICD-shock, and a standard Cox regression model was used for iii) all-cause mortality, iv) mortality rate following an ATP-therapy or ICD-shock. Cumulative incidence curves, generated using the Aalen Johansen estimator, were utilized to compare the incidence rates for ATP therapy and ICD-shock while accounting for competing risk of death, while Kaplan-Meier methodology was utilized for survival curves. Analyses were conducted in the total population and in subgroups divided on indication and device type. Results Out of 14 747 patients who received an ICD or CRT-D, 4377 (30%) had T2DM, 4593 (31%) patients received first-time appropriate ATP therapy or ICD-shock, and 1244 (8,4%) experienced first-time inappropriate treatments, 5 112 (35%) experienced death during the follow-up time (mean 3.9 years (SD 2.7)). T2DM patients were more likely to be male (85% vs 80%), slightly older (66 vs 65 years) and burdened with more comorbidities. No significant differences were seen between T2DM and non-T2DM patients for appropriate ATP therapy (HR 0.96[0.88:1.04] p=0.31), appropriate ICD-shock (HR 0.95[0.86:1.05] p=0.32), inappropriate ATP therapy (HR 0.92 [0.77;1.09] p=0.32) and inappropriate ICD-shock (HR 0.96 [0.78;1.18] p=0.71). In the subgroup analyses, no difference was seen in the primary prophylactic subgroups (Figure 1.), only significant difference was observed in the secondary prophylactic ICD group who received less ATP-therapy at 5-year follow-up (HR0.83[0.70;0.99] p=0.04), and in the secondary prophylactic CRT-D group, were T2DM patients seemed to experience more appropriate ICD-shock treatments (HR 2.07[1.23;3.48] p=0.006). Further, we found a higher mortality rate in T2DM with primary prophylactic ICD (HR 1.46[1.31;1.62] p<0.001) and secondary prophylactic ICD (HR 1.30[1.13;1.51] p<0.001), (Figure 2.) this mortality rate remained largely unchanged post appropriate ATP or ICD-shock in the ICD subgroups. Conclusions Despite similar incidence of ATP-therapy and ICD-shocks, T2DM patients with ICD-device experienced a significantly higher post-treatment mortality and all-cause mortality rate.

Amiodarone or Implantable Cardioverter-Defibrillator in Chagas Cardiomyopathy

Over 10 000 people with Chagas disease experience sudden cardiac death (SCD) annually, mostly caused by ventricular fibrillation. Amiodarone hydrochloride and the implantable cardioverter-defibrillator (ICD) have been empirically used to prevent SCD in patients with chronic Chagas cardiomyopathy. To test the hypothesis that ICD is more effective than amiodarone therapy for primary prevention of all-cause mortality in patients with chronic Chagas cardiomyopathy and moderate to high mortality risk, assessed by the Rassi score. CHAGASICS is an open-label, randomized clinical trial. The study enrolled patients from 13 centers in Brazil from May 30, 2014, to August 13, 2021, with the last follow-up November 8, 2021. Patients with serological findings positive for Chagas disease, a Rassi risk score of at least 10 points (intermediate to high risk), and at least 1 episode of nonsustained ventricular tachycardia were eligible to participate. Data were analyzed from May 3, 2022, to June 16, 2023. Patients were randomized 1:1 to receive ICD or amiodarone (with a loading dose of 600 mg after randomization). The primary outcome was all-cause mortality, and secondary outcomes included SCD, hospitalization for heart failure, and necessity of a pacemaker during the entire follow-up. The study was stopped prematurely for administrative reasons, with 323 patients randomized (166 in the amiodarone group and 157 in the ICD group), rather than the intended 1100 patients. Analysis was by intention to treat at a median follow-up of 3.6 (IQR, 1.8-4.4) years. Mean (SD) age was 57.4 (9.8) years, 185 patients (57.3%) were male, and the mean (SD) left ventricular ejection fraction was 37.0% (11.6%). There were 60 deaths (38.2%) in the ICD arm and 64 (38.6%) in the amiodarone group (hazard ratio [HR], 0.86 [95% CI, 0.60-1.22]; P = .40). The rates of SCD (6 [3.8%] vs 23 [13.9%]; HR, 0.25 [95% CI, 0.10-0.61]; P = .001), bradycardia requiring pacing (3 [1.9%] vs 27 [16.3%]; HR, 0.10 [95% CI, 0.03-0.34]; P < .001), and heart failure hospitalization (14 [8.9%] vs 28 [16.9%]; HR, 0.46 [95% CI, 0.24-0.87]; P = .01) were lower in the ICD group compared with the amiodarone arm. In patients with chronic Chagas cardiomyopathy at moderate to high risk of mortality, ICD did not reduce the risk of all-cause mortality. However, ICD significantly reduced the risk of SCD, pacing need, and heart failure hospitalization compared with amiodarone therapy. Further studies are warranted to confirm the evidence generated by this trial. ClinicalTrials.gov Identifier: NCT01722942.

Frequency of and outcomes associated with nonadherence to guideline-based recommendations for an implantable cardioverter-defibrillator in patients with congenital long QT syndrome

BackgroundGuideline-directed device therapy for long QT syndrome (LQTS) has evolved during the years, and indications for an implantable cardioverter-defibrillator (ICD) vary between professional cardiac societies. ObjectiveWe aimed to identify the subset of patients with LQTS who satisfied a class I or class II 2022 European Society of Cardiology guideline-based recommendation for an ICD and to determine the outcomes of those patients who received an ICD compared with those treated without an ICD. MethodsRetrospective analysis was conducted of 2861 patients with LQT1, LQT2, or LQT3 to identify patients meeting contemporary recommendations for guideline-directed device therapy. Basic demographics, clinical characteristics, and frequency/type of breakthrough cardiac events (BCEs) were extracted, and outcomes/complications were compared between patients treated with an ICD and those treated without one. ResultsOf the 290 patients (approximately 10%) who met a guideline-based recommendation, 53 (18%) satisfied a class I/level B indication for an ICD; 56 (19%), a class I/level C indication; 19 (7%), a class IIa/level C indication; and 162 (56%), a class IIb/level B indication. However, most patients (156/290 [54%]) did not receive an ICD. Of those who received an ICD, 55 of 134 (41%) experienced ≥1 appropriate ventricular fibrillation–terminating ICD therapy, whereas ICD-related complications occurred in 13 patients (10%). Of those who were treated without an ICD, only 6 of 154 patients (4%) had nonlethal BCEs, which was significantly lower compared with the ICD group (P < .001). ConclusionWith >1200 years of combined follow-up, the experience and evidence from our 2 LQTS specialty centers suggest that many patients who satisfy a recommendation for an ICD based on the latest 2022 European Society of Cardiology guidelines may not need one. This is particularly true when the indication stemmed from a BCE while receiving beta blocker therapy or in asymptomatic patients with an increased 1-2-3-LQTS-Risk score.

Wearable defibrillator to improve accuracy in selecting candidates to implantable defibrillator: A real-world experience.

The indication for implantable cardioverter defibrillator (ICD) for sudden cardiac death (SCD) prevention relies mostly on left ventricular ejection fraction (LVEF)≤35%. The use of a wearable cardioverter defibrillator (WCD) in the case of dynamic alterations of LVEF may help avoid an improper early ICD implant when a favourable evolution in the post-acute phase is observed and may help reduce costs. This parallel cohort retrospective study included patients with heart failure with reduced ejection fraction (HFrEF) at high risk of arrhythmias recruited in the acute phase and divided into an early ICD cohort and a WCD cohort for primary prevention during the waiting period established by European Society of Cardiology guidelines. A total of 41 consecutive patients were enrolled: 26 in the WCD group and 15 in the early ICD group. Age, LVEF at baseline, causes of HFrEF and drug therapy in the two cohorts were similar. During the waiting period after the inclusion, three patients (11.5%) in the WCD cohort and four (26.7%) in the early ICD cohort developed relevant ventricular arrhythmias (P=0.22); none of them had subsequent LVEF recovery. At the end of the waiting period, 13 patients (50%) in the WCD group and 7 (46.7%) in the early ICD group experienced LVEF recovery (P=0.84). The average cost per patient at the end of the waiting period was €23934 in the early ICD cohort versus €19167 in the WCD cohort (-19.9%). This cost savings from WCD use appears even higher when projected over a 10year period (-41.2%). WCD may represent a cost-effective strategy to more accurately select candidates for the primary prevention ICD implant among high-risk patients with HFrEF. ICD use provides effective protection from SCD and reduces costs compared with an extensive early ICD implant.

Perceived benefits of patient support groups and their format for people with an implantable cardioverter defibrillator

BackgroundSupport groups for people with Implantable Cardioverter Defibrillators (ICDs) are widely used, however, it is not clear what people with ICDs gain from a support group or what format they should take. ObjectivesThe aim of the present study is to define the perceived benefit of ICD support groups and develop practical recommendations for group format. Methods14 individuals with ICDs were interviewed using a semi-structured interview guide. Reflexive thematic analysis methods were utilised to code and analyse the transcripts before generating themes. ResultsFour themes were defined: confronting mortality, coping through sharing, coping through learning, and providing space. Making connections with other people with ICDs, reassurance, access to information, and advice from health care professionals were important perceived benefits of the support group. ConclusionPeople with ICDs may have to confront their own mortality and adapt to considerable life changes after implant. The findings from the present study have improved understanding of how support groups are perceived and how ICD indication and group format influence the experience. A blended format of in-person community meetings, online forums, HCP-led education and space for person-person interaction is recommended. Importantly, provision of support should not be time-limited to allow people to access it when it most likely to be of benefit to them.

Comparison of outcomes and required tools between transvenous extraction of pacemaker and implantable cardioverter defibrillator leads: Insight from single high-volume center experience.

Reports of comparison with procedural outcomes for implantable cardioverter defibrillator (ICD) and pacemaker (PM) transvenous lead extraction (TLE) are old and limited. We sought to compare the safety, efficacy, and procedural properties of ICD and PM TLE and assess the impact of lead age. The study cohort included all consecutive patients with ICD and PM TLE in the Cleveland Clinic Prospective TLE Registry between 2013 and 2022. Extraction success, complications, and failure employed the definitions described in the HRS 2017 TLE guidelines. A total of 885 ICD leads, a median implant duration of 8 (5-11) years in 810 patients, and 1352 PM leads of 7 (3-13) years in 807 patients were included. Procedural success rates in ICD patients were superior to those of PM in >20 years leads but similar in ≤20 years leads. In the PM group, the complete success rate of TLE decreased significantly according to the increase of lead age, but not in the ICD group. ICD TLE required more extraction tools compared with PM TLE but cases with older leads required non-laser sheath extraction tools in both groups. The most common injury site in major complication cases differed between ICD and PM TLE, although major complication rates showed no difference in both groups (2.7% vs. 1.6%, p = .12). The procedural success rate by TLE is greater for ICD patients than PM patients with leads >20 years old but requires more extraction tools. Common vascular complication sites and the impact of lead age on procedural outcomes and required tools differed between ICD and PM TLE.

Comparative Analysis of Response to Cardiac Resynchronisation Therapy Upgrades in Patients with Implantable Cardioverter-Defibrillators and Pacemakers.

Introduction: The efficacy of de novo cardiac resynchronisation therapy (CRT) in patients with heart failure (HF), left ventricular systolic dysfunction (LVSD), and a broad QRS morphology is well established. However, the optimal stage for upgrading patients with existing pacemakers (PPMs) or implantable cardioverter-defibrillators (ICDs) and HF with high-burden right ventricular (RV) pacing remains uncertain. Thus, this multicentre retrospective analysis compared patients with pre-existing PPMs or ICDs who underwent CRT upgrades to investigate the appropriate stage for CRT implantation in these patients and to assess the validity of treating both PPM and ICD recipients under the same recommendation level in the current guidelines. Materials and Methods: A total of 151 participants underwent analysis in this study, comprising 93 upgrades to cardiac resynchronisation therapy with pacemaker (CRT-P) and 58 upgrades to cardiac resynchronisation therapy with defibrillator (CRT-D) across three centres in the UK. The aim of the study was to investigate the safety and efficacy of upgrading to CRT from an existing conventional pacemaker or an ICD in the context of high-burden RV pacing. The analysis was conducted separately for each group, assessing changes in echocardiographic parameters, functional New York Heart Association (NYHA) class, and procedure-related complications. Results: The PPM group had a higher percentage RVP burden compared to the ICD group. Post-upgrade, NYHA functional class and EF and LV volumes improved in both groups; however, the response to an upgrade from a pacemaker was greater compared to an upgrade from an ICD. Post-procedural complication risks were similar across the two subgroups but significantly higher compared to de novo implantation. Conclusions: Within the CRT-P subgroup, participants exhibited better responses than their CRT-D counterparts, evident both in echocardiographic improvements and clinical outcomes. Furthermore, patients with non-ischemic cardiomyopathy (NICM) were better responders than those with ischaemic cardiomyopathy. These findings suggest that international guidelines should consider approaching each subgroup separately in the future.

An international multicenter cohort study on implantable cardioverter-defibrillators for the treatment of symptomatic children with catecholaminergic polymorphic ventricular tachycardia

BackgroundCatecholaminergic polymorphic ventricular tachycardia (CPVT) may cause sudden cardiac death (SCD) despite medical therapy. Therefore, implantable cardioverter-defibrillators (ICDs) are commonly advised. However, there is limited data on the outcomes of ICD use in children. ObjectiveThe purpose of this study was to compare the risk of arrhythmic events in pediatric patients with CPVT with and without an ICD. MethodsWe compared the risk of SCD in patients with RYR2 (ryanodine receptor 2) variants and phenotype-positive symptomatic CPVT patients with and without an ICD who were younger than 19 years and had no history of sudden cardiac arrest at phenotype diagnosis. The primary outcome was SCD; secondary outcomes were composite end points of SCD, sudden cardiac arrest, or appropriate ICD shocks with or without arrhythmic syncope. ResultsThe study included 235 patients, 73 with an ICD (31.1%) and 162 without an ICD (68.9%). Over a median follow-up of 8.0 years (interquartile range 4.3–13.4 years), SCD occurred in 7 patients (3.0%), of whom 4 (57.1%) were noncompliant with medications and none had an ICD. Patients with ICD had a higher risk of both secondary composite outcomes (without syncope: hazard ratio 5.85; 95% confidence interval 3.40–10.09; P < .0001; with syncope: hazard ratio 2.55; 95% confidence interval 1.50–4.34; P = .0005). Thirty-one patients with ICD (42.5%) experienced appropriate shocks, 18 (24.7%) inappropriate shocks, and 21 (28.8%) device-related complications. ConclusionSCD events occurred only in patients without an ICD and mostly in those not on optimal medical therapy. Patients with an ICD had a high risk of appropriate and inappropriate shocks, which may be reduced with appropriate device programming. Severe ICD complications were common, and risks vs benefits of ICDs need to be considered.

Is it safe to give birth with an activated implantable cardioverter-defibrillator: A multicentre observational study.

Data and guidelines are lacking, so implantable cardioverter-defibrillators (ICDs) are often deactivated during labour to prevent inappropriate shocks. This study aimed to ascertain the safety of an activated ICD during labour. An observational study was performed. Dutch hospitals. A total of 41 childbirths were included of 26 patients who gave birth between February 2009 and November 2018 after receiving an ICD in our tertiary hospital. Five of these childbirths were attended by the research team between December 2018 and August 2020, during which the ICD remained active. Groups were made based on ICD status during labour. Patients who gave birth with an activated ICD at least once were stratified to the activated ICD group. Patients' files were checked and patients received a questionnaire about childbirth perceptions and treatment preferences. The differences in ordinal data resulting from the questionnaire were calculated using a chi-square or Fisher's exact test. Primary outcome was inappropriate ICD therapy and occurrence of ventricular arrhythmias requiring treatment. During the 41 childbirths, no inappropriate shocks or ventricular arrhythmias occurred during labour. All patients in the activated ICD group (n = 13) preferred this setting, while 8 of the 13 patients in the deactivated ICD group preferred activation (p = 0.002). Reasons included avoiding hemodynamic monitoring, magnet placement, or labour induction to facilitate technician availability. This study shows no evidence that labour and birth in women with an activated ICD are unsafe, as there were no ventricular arrhythmias or inappropriate therapy. In addition, most patients prefer an activated ICD during labour.

Early ICD implantation following out-of-hospital cardiac arrest: a retrospective cohort study from the Swedish Registry for Cardiopulmonary Resuscitation

BackgroundIt is unclear whether an implantable cardioverter-defibrillator (ICD) is generally beneficial in survivors of out-of-hospital cardiac arrest (OHCA).ObjectiveWe studied the association between ICD implantation prior to discharge and survival in...

Long-Term Outcomes of Resynchronization–Defibrillation for Heart Failure

BackgroundThe Resynchronization–Defibrillation for Ambulatory Heart Failure Trial (RAFT) showed a greater benefit with respect to mortality at 5 years among patients who received cardiac-resynchronization therapy (CRT) than among those who received implantable cardioverter–defibrillators (ICDs). However, the effect of CRT on long-term survival is not known.MethodsWe randomly assigned patients with New York Heart Association (NYHA) class II or III heart failure, a left ventricular ejection fraction of 30% or less, and an intrinsic QRS duration of 120 msec or more (or a paced QRS duration of 200 msec or more) to receive either an ICD alone or a CRT defibrillator (CRT-D). We assessed long-term outcomes among patients at the eight highest-enrolling participating sites. The primary outcome was death from any cause; the secondary outcome was a composite of death from any cause, heart transplantation, or implantation of a ventricular assist device.ResultsThe trial enrolled 1798 patients, of whom 1050 were included in the long-term survival trial; the median duration of follow-up for the 1050 patients was 7.7 years (interquartile range, 3.9 to 12.8), and the median duration of follow-up for those who survived was 13.9 years (interquartile range, 12.8 to 15.7). Death occurred in 405 of 530 patients (76.4%) assigned to the ICD group and in 370 of 520 patients (71.2%) assigned to the CRT-D group. The time until death appeared to be longer for those assigned to receive a CRT-D than for those assigned to receive an ICD (acceleration factor, 0.80; 95% confidence interval, 0.69 to 0.92; P=0.002). A secondary-outcome event occurred in 412 patients (77.7%) in the ICD group and in 392 (75.4%) in the CRT-D group.ConclusionsAmong patients with a reduced ejection fraction, a widened QRS complex, and NYHA class II or III heart failure, the survival benefit associated with receipt of a CRT-D as compared with ICD appeared to be sustained during a median of nearly 14 years of follow-up. (RAFT ClinicalTrials.gov number, NCT00251251.)

Effect of implantable cardioverter-defibrillator in non-ischaemic systolic heart failure according to the Heart Failure Collaboratory Medical Therapy Score: extended follow-up of the DANISH trial

Abstract Background The Heart Failure Collaboratory (HFC) has developed a medical therapy score which integrates types and doses of guideline-directed pharmacotherapies in patients with systolic heart failure, providing a measure of treatment quality. In clinical trials, this score may help determine the additive effect of new treatments. In the Danish Study to Assess the Efficacy of Implantable Cardioverter Defibrillators (ICDs) in Patients with Non-ischaemic Systolic Heart Failure on Mortality (DANISH) trial, ICD implantation did not provide an overall survival benefit in patients with non-ischaemic systolic heart failure. Purpose Adding four years of additional follow-up to the DANISH trial, we examined the effect of ICD implantation according to baseline modified HFC (mHFC) medical therapy score. Methods In the DANISH trial, 1,116 patients with non-ischaemic systolic heart failure were randomised to receive an ICD (N = 556) or usual clinical care (N = 560, control group). The primary outcome was death from any cause. In the mHFC score, patients were assigned a score for each drug class of the original cornerstones of systolic heart failure treatment (renin-angiotensin-system inhibitor, beta-blocker, and mineralocorticoid receptor antagonist). The maximum score was 100%, corresponding to optimal medical therapy with all three types of medication (=&amp;gt;50% of target dose). Results The median mHFC score at baseline was 67% (25th-75th percentile, 67%-100%; range, 17%-100%). During a median follow-up of 9.5 years, the ICD group did not have significantly lower all-cause mortality compared with the control group (hazard ratio [HR] 0.89 [95% CI, 0.74-1.08]). The results were independent of the mHFC score at baseline (mHFC score = &amp;lt; median: HR 0.91 [95% CI, 0.70-1.19]; mHFC score &amp;gt; median: HR 0.87 [95% CI, 0.66-1.14]; P for interaction, 0.94). Similarly, ICD implantation did not reduce the rate of cardiovascular death overall (HR 0.87 [95% CI, 0.70-1.09]), and this association was not modified by the mHFC score (mHFC score = &amp;lt; median: HR 0.90 [95% CI, 0.65-1.24]; mHFC score &amp;gt; median: HR 0.84 [95% CI, 0.61-1.15]; P for interaction, 0.89). The ICD group had a significantly lower rate of sudden cardiovascular death in the overall population (HR, 0.60 [95% CI, 0.40-0.92]), and this association was not modified by the mHFC score (mHFC score = &amp;lt; median: HR 0.72 [95% CI, 0.40-1.29]; mHFC score &amp;gt; median: HR 0.53 [95% CI, 0.28-0.99]; P for interaction, 0.59). See Figure for results. Conclusions In this extended follow-up study of the DANISH trial, ICD implantation did not provide an overall survival benefit in patients with non-ischaemic systolic heart failure regardless of baseline medical heart failure therapy, assessed by the mHFC score.Modified HFC score in the DANISH trial

Early ICD implantation and survival after out-of-hospital cardiac arrest

Abstract Background It is unclear whether an implantable cardioverter-defibrillator (ICD) is generally beneficial in survivors of out-of-hospital cardiac arrest (OHCA) of cardiac etiology. Aim We studied the association between ICD implantation and survival in patients with cardiac etiology or initial shockable rhythm in OHCA, using the Swedish Registry for Cardiopulmonary Resuscitation (SRCR). Methods All cases in the SRCR during 2010 to 2020 with cardiac etiology or initial shockable rhythm who were discharged alive included. We examined the association between ICD and survival using propensity score. Propensity scores (919 candidate predictors before feature selection) were estimated using gradient boosting, Bayesian additive regression trees, neural networks, extreme gradient boosting and logistic regression. Cox regression was used to model survival. The primary outcome was death or recurrent cardiac arrest. Results The 90-days event rate was 25% in the ICD group, compared with 52% in those without ICD. With regards to the average treatment effect (ATE) the overall hazard ratio 0.38 (95% CI 0.26-0.56) for ICD vs. no ICD. The overall average treatment effect on those treated (ATT) was 0.31 (95% CI 0.22-0.44). In the 15 subgroup analyses, every point estimate were below 1, with the most pronounced association noted in those with a history of acute myocardial infarction (HR 0.07 [95% CI 0.02-0.32]). All ATE and ATE estimates were aligned. Conclusions Mortality in survivors of OHCA occurs early after discharge, and prompt implantation of an ICD is associated with 62% lower probability of death and recurrent cardiac arrest overall.

Abstract 12506: Implantable Cardioverter Defibrillators for Primary Prevention in Patients With Ischemic and Non Ischemic Cardiomyopathy: A Meta-Analysis of 15 Randomized Controlled Trial

Background: The evidence to support implantable cardioverter defibrillator (ICD) in patients with ischemic and nonischemic cardiomyopathy for prevention of sudden cardiac death (SCD) is not robust, with conflicting results in randomized controlled trials. Objective: We aim to evaluate the impact of ICD therapy with conventional care for the primary prevention of death of various causes in adults with ischemic and nonischemic cardiomyopathy. Methods: We performed a systematic literature search on the electronic database for relevant articles from inception until 15th May 2022. Results: A total of 15 randomized controlled trials involving 9,999 patients: 9 (6523 patients) addressed ischemic cardiomyopathy, and 6 studies (3476 patients) reported nonischemic cardiomyopathy. The mean follow-up duration was 3.02 years. Pooled analysis showed that ICD therapy significantly reduced the risk of ACM (HR, 0.75(95%CI: 0.64-0.88), P&lt;0.001) from the control group. The magnitude of reduction was similar with ischemic (HR, 0.75(95%CI: 0.58-0.96), P=0.02), nonischemic (HR, 0.76(95%CI: 0.64-0.90), P&lt;0.01). There was 67% reduction in SCD among ICD therapy group (OR, 0.33(95%CI: 0.25-0.44), P&lt;0.00001) compared to the control, a similar trend was observed in both ischemic (OR, 0.39(95%CI: 0.28-0.56), P&lt;0.00001), and nonischemic cardiomyopathy (OR, 0.24(95%CI: 0.15-0.38), P&lt;0.00001). The ICD therapy group had a significant reduction of 65% reduction in arrhythmia-related death compared to control in ischemic cardiomyopathy (OR, 0.35(95%CI: 0.19-0.64), P&lt;0.001). However, there was a trend of 23% in cardiovascular mortality in the ICD group (OR, 0.77(95%CI: 0.58-1.02), P=0.07) but unable to reach statistical significance. Conclusion: Overall, primary prevention with ICD therapy reduced the incidence of all-cause mortality and sudden cardiac death among ischemic and nonischemic cardiomyopathy patients.

Outcomes of catheter ablation in high-risk patients with Brugada syndrome refusing an implantable cardioverter defibrillator implantation.

The aim of this study was to investigate the outcomes of catheter ablation (CA) in preventing arrhythmic events among patients with symptomatic Brugada syndrome (BrS) who declined implantable cardioverter defibrillator (ICD) implantation. A total of 40 patients with symptomatic BrS were included in the study, of which 18 refused ICD implantation and underwent CA, while 22 patients received ICD implantation. The study employed substrate modification (including endocardial and epicardial approaches) and ventricular fibrillation (VF)-triggering pre-mature ventricular contraction (PVC) ablation strategies. The primary outcomes were a composite endpoint consisting of episodes of VF and sudden cardiac death during the follow-up period. The study population had a mean age of 43.8 ± 9.6 years, with 36 (90.0%) of them being male. All patients exhibited the typical Type 1 BrS electrocardiogram pattern, and 16 (40.0%) were carriers of an SCN5A mutation. The Shanghai risk scores were comparable between the CA and the ICD groups (7.05 ± 0.80 vs. 6.71 ± 0.86, P = 0.351). Ventricular fibrillation-triggering PVCs were ablated in 3 patients (16.7%), while VF substrates were ablated in 15 patients (83.3%). Epicardial ablation was performed in 12 patients (66.7%). During a median follow-up of 46.2 (17.5-73.7) months, the primary outcomes occurred more frequently in the ICD group than in the CA group (5.6 vs. 54.5%, Log-rank P = 0.012). Catheter ablation is an effective alternative therapy for improving arrhythmic outcomes in patients with symptomatic BrS who decline ICD implantation. Our findings support the consideration of CA as an alternative treatment option in this population.

Upgrade of right ventricular pacing to cardiac resynchronization therapy in heart failure: a randomized trial.

De novo implanted cardiac resynchronization therapy with defibrillator (CRT-D) reduces the risk of morbidity and mortality in patients with left bundle branch block, heart failure and reduced ejection fraction (HFrEF). However, among HFrEF patients with right ventricular pacing (RVP), the efficacy of CRT-D upgrade is uncertain. In this multicentre, randomized, controlled trial, 360 symptomatic (New York Heart Association Classes II-IVa) HFrEF patients with a pacemaker or implantable cardioverter defibrillator (ICD), high RVP burden ≥ 20%, and a wide paced QRS complex duration ≥ 150 ms were randomly assigned to receive CRT-D upgrade (n = 215) or ICD (n = 145) in a 3:2 ratio. The primary outcome was the composite of all-cause mortality, heart failure hospitalization, or <15% reduction of left ventricular end-systolic volume assessed at 12 months. Secondary outcomes included all-cause mortality or heart failure hospitalization. Over a median follow-up of 12.4 months, the primary outcome occurred in 58/179 (32.4%) in the CRT-D arm vs. 101/128 (78.9%) in the ICD arm (odds ratio 0.11; 95% confidence interval 0.06-0.19; P < .001). All-cause mortality or heart failure hospitalization occurred in 22/215 (10%) in the CRT-D arm vs. 46/145 (32%) in the ICD arm (hazard ratio 0.27; 95% confidence interval 0.16-0.47; P < .001). The incidence of procedure- or device-related complications was similar between the two arms [CRT-D group 25/211 (12.3%) vs. ICD group 11/142 (7.8%)]. In pacemaker or ICD patients with significant RVP burden and reduced ejection fraction, upgrade to CRT-D compared with ICD therapy reduced the combined risk of all-cause mortality, heart failure hospitalization, or absence of reverse remodelling.

Single- Versus Dual-Chamber Implantable Cardioverter-Defibrillator for Primary Prevention of Sudden Cardiac Death in the United States.

Background Routine addition of an atrial lead during an implantable cardioverter-defibrillator (ICD) implantation for primary prevention of sudden cardiac death, in patients without pacing indications, was not shown beneficial in contemporary studies. We aimed to investigate the use and safety of single- versus dual-chamber ICD implantations in these patients. Methods and Results Using the National Inpatient Sample database, we identified patients with no pacing indications who underwent primary-prevention ICD implantation in the United States between 2015 and 2019. Sociodemographic and clinical characteristics, as well as in-hospital complications, were analyzed. Multivariable logistic regression was used to identify predictors of in-hospital complications. An estimated total of 15 940 patients, underwent ICD implantation for primary prevention of sudden cardiac death during the study period, 8860 (55.6%) received a dual-chamber ICD. The mean age was 64 years, and 66% were men. In-hospital complication rates in the dual-chamber ICD and single-chamber ICD group were 12.8% and 10.7%, respectively (P<0.001), driven by increased rates of pneumothorax/hemothorax (4.6% versus 3.4%; P<0.001) and lead dislodgement (3.6% versus 2.3%; P<0.001) in the dual-chamber ICD group. Multivariable analyses confirmed atrial lead addition as an independent predictor for "any complications" (odds ratio [OR], 1.1 [95% CI, 1.0-1.2]), for pneumo/hemothorax (odds ratio, 1.1 [95% CI, 1.0-1.4]), and for lead dislodgement (odds ratio, 1.3 [95% CI, 1.1-1.6]). Conclusions Despite lack of evidence for clinical benefit, dual-chamber ICDs are implanted for primary prevention of sudden cardiac death in a majority of patients who do not have pacing indication. This practice is associated with increased risk of periprocedural complications. Avoidance of routine implantation of atrial leads will likely improve safety outcomes.

Cardiac resynchronization therapy: potential for arrhythmic risk modification

Aim. To evaluate the impact of cardiac resynchronization therapy (CRT) on the risk of sustained ventricular tachyarrhythmias (VT) in patients with heart failure (HF) with a implantable cardioverter-defibrillator (ICD) for the primary prevention of sudden cardiac death.Material and methods. This single-center prospective clinical study included 470 patients (men, 84%) with HF at the age of 57 (51-62) years with a left ventricular ejection fraction (LVEF) of 29 (25-33)%. There were following exclusion criteria: indications for cardiac surgery, known channelopathies, previously registered VT. Depending on intraventricular conduction disorders, dual-chamber ICDs (42%) or CRT-D (58%) were implanted. After ICD implantation, patients were followed up for 24 months to register the end point — a first-time sustained paroxysm of VT detected by the ICD. A positive response to CRT was established in the case of an increase in LVEF by ≥5% of the initial level.Results. A total of 388 patients underwent full postoperative follow-up. The studied arrhythmic endpoint occurred on average 21 (0,6) months after implantation in 104 patients (27%) with higher frequency in the ICD group. However, the differences in the VT rate in the study groups were statistically unreliable (30% in the ICD group versus 24% in the CRT-D group, p=0,142). It was found that the VT rate was reliably lower in CRT-responders (118 patients, 53%): 15% compared to 32% in the group of inefficient CRT. A 5% increase in the LFEF reduced the probability of VT occurrence by 3 times (odds ratio [OR]=0,34; 95% of CI: 0,13-0,86; p=002). Significant modification of arrhythmic risk was verified by increasing LFEF to 36-40% (OR=0,72; 95% CI: 0,63-0,82; p=0,04).Conclusion. The results obtained indicate that effective CRT has the potential to modify arrhythmic risk in patients with HF, especially with an increase in LVEF to the level of 36-40%.

Ventricular arrhythmias and cardiac arrest in atrial fibrillation patients with pacemakers and implantable cardioverter-defibrillators

BackgroundAtrial fibrillation (AF) has been linked to ventricular arrhythmias (VAs) and sudden death, but few studies have specifically explored this association. ObjectiveWe investigated whether AF is associated with an increased risk of ventricular tachycardia (VT), ventricular fibrillation (VF) and cardiac arrests (CA) in patients with cardiac implantable electronic devices (CIEDs). MethodsAll patients with pacemakers and implantable cardioverter-defibrillators (ICDs) hospitalised between 2010 and 2020 were identified from the French National database. Patients with a prior history of VT/VF/CA were excluded. Results701,195 patients were identified initially. After excluding 55,688 patients, 581,781 (90.1%) and 63,726 (9.9%) remained in the pacemaker and ICD groups respectively. 248,046 (42.6%) pacemaker patients had AF and 333,735 (57.4%) had no AF, whereas in the ICD group 20,965 (32.9%) had AF and 42,761 (67.1%) had no AF. The incidence of VT/VF/CA was higher in AF patients compared to non-AF patients both in pacemaker (1.47%/year vs. 0.94%/year) and ICD (5.30%/year vs. 4.21%/year) groups. After multivariable analysis, AF was independently associated with an increased risk of VT/VF/CA in pacemaker (HR 1.236 [95% CI 1.198–1.276]) and ICD (HR 1.167 [95% CI 1.111–1.226]) patients. This risk was still significant in the 1:1 propensity score-matched analysis of the pacemaker (n = 200,977 per subgroup) and ICD cohorts (n = 18,349 per subgroup), HR 1.230 [95% CI 1.187–1.274] and HR 1.134 [95% CI 1.071–1.200] respectively and in the competing risk analysis (pacemaker: HR 1.195 (95% CI 1.154–1.238], ICD: HR 1.094 [95% CI 1.034–1.157]). ConclusionCIED patients with AF have a higher risk of VT/VF/CA compared to CIED patients without AF.

Long-term Clinical Outcomes of Implantable Cardioverter Defibrillator Recipients in New Zealand

The long-term clinical outcomes of implantable cardioverter defibrillator (ICD) recipients across New Zealand are unknown. This study provides a detailed analysis of long-term clinical outcomes of ICD recipients in New Zealand over the past decade. All patients with an ICD implant between 2010 and 2019 were identified using the National Minimum Dataset, which collects all public hospital admissions in New Zealand using International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification (ICD10-AM) procedure coding. There were 4,261 patients with a mean follow-up of 4.85±2.76 years. There were 1,739 (40.8%) primary prevention and 2,522 (59.2%) secondary prevention ICD recipients. The median age was 62 years and 78.9% were male. There was no significant difference in all-cause mortality between primary prevention or secondary prevention ICD recipients (21.7% vs 21.9%, p=0.99). In the primary prevention ICD group, heart failure (HF) hospitalisation more frequently occurred (32.7% vs 26.1%, p<0.001) but hospitalisations with ventricular arrhythmia (VA) were less common (16.7% vs 27.1%, p<0.001). Compared with ICD recipients with non-ischaemic aetiology for HF, those with ischaemic HF had higher all-cause mortality (30.0% vs 16.1%, p<0.001), HF hospitalisation (38.0% vs 22.4%, p<0.001), and hospitalisation with VA (27.9% vs 19.4%, p<0.001). In New Zealand ICD recipients, there was no difference in all-cause mortality between primary prevention and secondary prevention ICD implants. However, ICD recipients with ischaemic aetiology for HF had significantly higher all-cause mortality, HF hospitalisation, and hospitalisation with VA.