Implantable Cardioverter Defibrillator Indication Research Articles

The triglyceride-glucose index, ventricular arrhythmias and major cardiovascular events in patients at high risk of sudden cardiac death

BackgroundThe association between the triglyceride-glucose (TyG) index and ventricular arrhythmias (VAs) is unclear. This study aimed to investigate the relationship between the TyG index, VAs, and major cardiovascular events in patients at high risk of sudden cardiac death (SCD).MethodsWe enrolled 1046 patients at high risk of SCD with an indication for implantable cardioverter-defibrillator (ICD) implantation at the Chinese National Center for Cardiovascular Diseases. The primary outcome was VAs, defined as sustained ventricular tachycardia and ventricular fibrillation documented by the ICD. The secondary outcomes were cardiac mortality, heart transplantation, and rehospitalization for heart failure.ResultsThe mean (± SD) age was 59.6 ± 14.0 years old, and 25.7% were female. During the mean follow-up of 36.1 months, 342 (32.7%) patients had VAs, and 185 (17.7%) patients had major cardiovascular events. The mean fasting glucose and triglyceride levels were 111.9 ± 42.7 mg/dL and 140.0 ± 95.4 mg/L, respectively, with a TyG index range of 6.96–11.8. In the Fine-Gray subdistribution hazard model analysis, an increase in the TyG index was associated with a significant increase in the VAs (per 1 TyG index, hazard ratio [HR] 2.95; 95% confidence interval [CI], 2.29–3.80) and secondary outcome (HR 2.84; 95% CI 1.86–4.34). When stratified into tertiles, the risk of VAs was significantly higher in the highest tertile (HR 4.08; 95% CI, 2.81–5.92) than in the lowest tertile. Analysis of the secondary outcome revealed similar findings (HR 3.18; 95% CI, 1.73–5.85).ConclusionsIn our cohort, the pre-operational TyG index is significantly associated with VAs and major cardiovascular events for patients with high risk of SCD.

Assessment of Antitachycardia Pacing in Primary Prevention Patients

The emergence of novel programming guidelines that reduce premature and inappropriate therapies along with the availability of new implantable cardioverter-defibrillator (ICD) technologies lacking traditional endocardial antitachycardia pacing (ATP) capabilities requires the reevaluation of ATP as a first strategy in terminating fast ventricular tachycardias (VTs) in primary prevention ICD recipients. To assess the role of ATP in terminating fast VTs in primary prevention ICD recipients with contemporary programming. This global, prospective, double-blind, randomized clinical trial had an equivalence design with a relative margin of 35%. Superiority tests were performed at interim analyses and the final analysis if equivalence was not proven. Patients were enrolled between September 2016 and April 2021 at 134 sites in 8 countries, with the last date of follow-up on July 6, 2023. Patients were required to have an indication for a primary prevention ICD, including left ventricular ejection fraction less than or equal to 35%. Patients were randomized in a 1:1 ratio to receive ATP plus shock vs shock only. The primary end point was time to first all-cause shock. Secondary end points included time to first appropriate shock, time to first inappropriate shock, all-cause mortality, and the composite of time to first all-cause shock plus all-cause mortality. A total of 2595 patients were randomized (mean age, 63.9 years; 22.4% were females). At a mean follow-up of 38 months, first all-cause shock occurred in 129 participants in the ATP plus shock group and 178 participants in the shock only group. The hazard ratio (HR) for the primary end point was 0.72 (95.9% CI, 0.57-0.92), with P = .005 for superiority of the ATP plus shock group over the shock only group. During follow-up in an intention-to-treat analysis, the total shock burden per 100 patient-years was not statistically different, at 12.3 and 14.9, respectively (P = .70). The use of a single burst of ATP prior to shock in primary prevention ICD recipients with modern ICD detection programming prolonged the time to first all-cause ICD shock. ClinicalTrials.gov Identifier: NCT02923726.

Machine Learning-Based Clustering Using a 12-Lead Electrocardiogram in Patients With a Implantable Cardioverter Defibrillator to Identify Future Ventricular Arrhythmia.

Implantable cardioverter defibrillators (ICDs) reduce mortality associated with ventricular arrhythmia in high-risk patients with cardiovascular disease. Machine learning (ML) approaches are promising tools in arrhythmia research; however, their application in predicting ventricular arrhythmias in patients with ICDs remains unexplored. We aimed to predict and stratify ventricular arrhythmias requiring ICD therapy using 12-lead electrocardiograms (ECGs) in patients with an ICD. This retrospective analysis included 200 adult patients who underwent ICD implantation at a single center. Patient demographics, clinical features, and 12-lead ECG data were collected. Unsupervised learning techniques, including K-means and hierarchical clustering, were used to stratify patients based on 12-lead ECG features. Dimensionality reduction methods were also used to optimize clustering accuracy. The silhouette coefficient was used to determine the optimal method and number of clusters. Of the 200 patients, 59 (29.5%) received appropriate therapy. The mean age of patients was 62.3 years, and 81.0% were male. The mean follow-up period was 2,953 days, with no significant intergroup differences. Hierarchical clustering into 3 clusters proved to be the most accurate (silhouette coefficient=0.585). Kaplan-Meier curves for these 3 clusters revealed significant differences (P=0.026). We highlight the potential of ML-based clustering using 12-lead ECGs to help in the risk stratification of ventricular arrhythmia. Future research in a larger multicenter setting may provide further insights and refine ICD indications.

Appropriate use of wearable defibrillators with multiparametric evaluation to avoid unnecessary defibrillator implantation

IntroductionWearable cardioverter-defibrillators (WCD) have emerged as a valuable tool in the management of patients at risk for life-threatening arrhythmias. These devices offer a non-invasive and temporary solution, providing continuous monitoring...

Abstract Tu060: Unveiling Arrhythmogenic Right Ventricular Dysplasia In Pregnancy

Introduction: Arrhythmogenic right ventricular dysplasia (ARVD) is a rare autosomal dominant disease, caused by desmosomal gene mutations, and characterized by fibrofatty replacement of right ventricular (RV) myocardium with left ventricular (LV) involvement in advanced stages. It is mostly diagnosed between the second and forth decades of life and can present with ventricular tachycardia and arrhythmic sudden death. Here we present a case of ARVD diagnosis in a female in her forth pregnancy. Case description: A 28-year-old female, on her 27 th week of gestation (G4P3) was admitted to the hospital with preterm premature rupture of membranes. She also endorsed intermittent chest pressure, palpitations and shortness of breath. Her vital signs were stable, and electrocardiogram (ECG) revealed normal sinus rhythm with frequent premature ventricular contractions (PVCs) and T wave inversions in leads V1- V3. Laboratory studies showed normal troponin and D-dimer levels, and slightly elevated brain natriuretic peptide 240 pg/mL. Patient notably had frequent runs of monomorphic non-sustained ventricular tachycardia (NSVT) arising from RV apical territory, with left bundle branch morphology on telemetry. An echocardiogram revealed a dilated right atrium and RV with hypokinesis of RV; LV size and function were normal. Overall, patient met the revised task force diagnostic criteria for ARVD based on PVC morphology, abnormal ECG and dilated and hypokinetic RV. She had no sustained or hemodynamically unstable VT, no history of syncope or family history of sudden cardiac death and did not meet class I indication for implantable cardioverter defibrillator. She was started on oral metoprolol succinate 25 mg daily with which her arrhythmias significantly improved. She was recommended a cardiac magnetic resonance imaging and genetic testing for confirmation and to assess familial implications. Conclusion: Recognition of ARVD during pregnancy is challenging given the overlapping symptoms of normal pregnancy-related changes. Hormonal surge and sympathetic drive may have driven the increased frequency of NSVT in our patient and beta blocker was effective in managing these. Early recognition and tailored management are crucial to ensure the well-being of both the mother and the fetus. A close follow-up is necessary to understand the long-term implications for the patient and potential genetic predisposition in the family.

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.

Arrhythmic prognosis according to left ventricular systolic dysfunction severity in cardiac sarcoidosis

BackgroundCurrent guidelines present varying classes of recommendations for implantable cardioverter-defibrillator (ICD) utilization in patients with cardiac sarcoidosis (CS) and left ventricular ejection fraction (LVEF) <50%. ObjectiveThe purpose of this study was to investigate the ventricular arrhythmia risk in CS patients with ICDs and varying degrees of left ventricular systolic dysfunction. MethodsThe study included CS patients with an ICD and LVEF <50% at index evaluation. The primary outcome was survival free of sustained ventricular tachycardia (VT)/ventricular fibrillation (VF) after ICD implantation and was assessed comparatively for LVEF ≤35% vs 36%–49% and for primary vs secondary prevention ICD indication. ResultsThe study included 61 patients (median age 57 years; 61% male) with LVEF 36%–49% (n = 23) or LVEF ≤35% (n = 38). An ICD was implanted for secondary prevention in 24% and 44% of the LVEF ≤35% and 36%–49% groups, respectively (P = .11). The primary outcome did not differ between the 2 groups in univariable analysis (LVEF ≤35% vs 36%–49%: hazard ratio [HR] 0.85; 95% confidence interval [CI] 0.39–1.82; P = .67). In multivariable analysis, secondary prevention ICD indication was the only significant predictor of incident sustained VT/VF (HR 2.86; 95% CI 1.23–6.67; P = .015). Mean sustained VT/VF event burden was higher in the secondary compared with the primary prevention ICD patients (0.47 vs 0.11 events per patient-year; P = .005) but did not differ significantly between LVEF ≤35% and 36%–49% patients. ConclusionCS patients with ICD indications and LVEF 36%–49% carry similarly high arrhythmic risk as those with LVEF ≤35%. Patients with secondary prevention ICDs have the highest overall risk.

A comparison of symptoms of anxiety and depression in patients with a primary and secondary prophylactic indication for an implantable cardioverter defibrillator. [Data from the ACQUIRE-ICD RCT

Abstract Introduction Indication for the implantable cardioverter defibrillator (ICD) is either primary or secondary prophylactic. Symptoms of anxiety and depression are known to be evident in patients with an ICD. However, research has not shown agreement in whether there is a difference in the degree of symptoms in these two indication groups. Purpose We investigated the association between anxiety and depression and indication for ICD from implantation and up to 24 months of follow-up. Methods Data was derived from a national randomized controlled trial the "Web-based healthcare innovation to advance the quality of life and care of patients with an implantable cardioverter defibrillator [ACQUIRE-ICD]" to perform a secondary analysis. A total of 478 patients with a first-time ICD were included and completed the Generalized Anxiety Disorder Assessment (GAD-7) and the Patient Health Questionnaire (PHQ-9) after ICD implantation and at 6, 12 and 24 months. Mixed effects regression models and estimated marginal means were used to analyze longitudinal data. Results Anxiety mean scores did not differ statistically between patients with a primary prophylactic ICD as compared to patients with a secondary prophylactic ICD. Most patients showed limited symptoms of anxiety. However, 9% reported values above the cut-off for clinical relevant anxiety. Depression mean scores were significantly higher at 24 months in patients with primary prophylactic ICD as compared to patients with a secondary prophylactic ICD (mean 4.15 vs. 3.05; p=0.014) but not statistically significant at other time points. Most patients showed limited levels of depression. However, 13.2% reported values above the cut-off for clinical relevant depression. Both anxiety and depression scores decreased over time from baseline in both groups. Conclusion Patients with a primary prophylactic ICD did not differ in symptoms of anxiety and had mostly the same level of depression as compared to patients with a secondary prophylactic ICD. However, at 24 months patients with a primary prophylactic ICD reported more symptoms of depression as compared to patients with a secondary prophylactic ICD.Table 1

Depression and Implantable Cardioverter-Defibrillator Implantation in Black Patients at Risk for Sudden Cardiac Death.

Black patients meeting indications for implantable cardioverter-defibrillators (ICDs) have lower rates of implantation compared with White patients. There is little understanding of how mental health impacts the decision-making process among Black patients considering ICDs. Our objective was to assess the association between depressive symptoms and ICD implantation among Black patients with heart failure. This is a secondary analysis of the VIVID (Videos to Address Racial Disparities in ICD Therapy via Innovative Designs) randomized trial, which enrolled self-identified Black individuals with chronic systolic heart failure. Depressive symptoms were assessed by the Patient Health Questionnaire-2 and the Mental Component Summary of the 12-Item Short-Form Health Survey. Decisional conflict was measured by an adapted Decisional Conflict Scale (DCS). ANCOVA was used to assess differences in Decisional Conflict Scale scores. Multivariable logistic regression was used to examine the association between depressive symptoms and ICD implantation. Among 306 participants, 60 (19.6%) reported depressed mood, and 142 (46.4%) reported anhedonia. Participants with the lowest Mental Component Summary of the 12-Item Short-Form Health Survey scores (poorer mental health and higher likelihood of depression) had greater decisional conflict regarding ICD implantation compared with those with the highest Mental Component Summary of the 12-Item Short-Form Health Survey scores (adjusted mean difference in Decisional Conflict Scale score, 3.2 [95% CI, 0.5-5.9]). By 90-day follow-up, 202 (66.0%) participants underwent ICD implantation. There was no association between either the Patient Health Questionnaire-2 score or the Mental Component Summary of the 12-Item Short-Form Health Survey score and ICD implantation. Depressed mood and anhedonia were prevalent among ambulatory Black patients with chronic systolic heart failure considering ICD implantation. The presence of depressive symptoms did not impact the likelihood of ICD implantation in this population.

Plasmatic NT-proBNP is strongly associated with atrial fibrillation in patients without severely reduced left ventricular ejection fraction in an ICD collective

Abstract Background and objectives Atrial fibrillation is common in patients with chronic heart failure and associated with poor outcome in these patients. Plasmatic NT-proBNP represents the gold standard biomarker for chronic heart failure. Further, a recent analysis showed a strong association of plasmatic NT-proBNP and atrial fibrillation (AFib). Aim of the study was to assess the association of plasmatic NT-proBNP depending on left ventricular ejection fraction (LVEF) in a cohort of patients with implantable cardioverter defibrillator (ICD). Methods 412 patients were included in the study. Blood samples were used to assess plasmatic NT-proBNP. Follow-up was performed after 45 months. LVEF was estimated by echocardiography according to Simpsons’ method. At enrollment, a 12-lead electrocardiogram was performed (sinus rhythm (SR, n = 306), atrial fibrillation (AFib, n = 79)). Patients were divided into two subgroups by LVEF of 40%. Results Patients suffering from severely reduced LVEF ≤ 40% showed significant higher age, higher rates of chronic kidney disease, diabetes, coronary artery disease, primary prevention ICD indication, coronary artery disease, dilatative cardiomyopathy and plasmatic NT-proBNP compared to patients with LVEF &amp;gt; 40% (each p &amp;lt; 0.05). There were no differences regarding hypertension and occurrence of AFib between patients with LVEF ≤ 40% compared to patients with LVEF &amp;lt; 40% (each p = n.s.). In ROC analysis there was a significantly higher AUC in patients with LVEF &amp;gt; 40% (AUC: 0.87, IQR 0.82-0.92) compared to patients with severely reduced LVEF ≤ 40% (AUC: 0.72, IQR 0.64-0.80) regarding plasmatic NT-proBNP and prediction of AFib (p &amp;lt; 0.002). In patients with LVEF &amp;gt; 40% plasmatic NT-proBNP was shown as significant predictor regarding existence of atrial fibrillation in binary logistic regression analysis, beside age (p &amp;lt; 0.05). Diabetes, hypertension, serum creatinine, coronary artery disease and primary prevention ICD indication were no significant predictors (p = n.s.). In patients with LVEF ≤ 40% plasmatic NT-proBNP was not shown as significant predictor regarding existence of atrial fibrillation in binary logistic regression analysis. Conclusion Elevated levels of plasmatic NT-proBNP are strongly associated with the prevalence of atrial fibrillation in patients without severely reduced LVEF in a cohort of ICD patients.

Plasmatic NT-proBNP is strongly associated with atrial fibrillation in patients with Implantable cardioverter defibrillator

Abstract Background and objectives Atrial fibrillation is common in patients with chronic heart failure and associated with poor outcome in these patients. Plasmatic NT-proBNP represents the gold standard biomarker for chronic heart failure. Further, recent studies showed prognostic impact of urinary NT-proBNP. Aim of the study was to assess the association of plasmatic as well as urinary NT-proBNP and atrial fibrillation in a cohort of patients with implantable cardioverter defibrillator (ICD). Methods 412 patients were included in the study. Fresh spot urine and blood samples were used to assess urinary as well as plasmatic NT-proBNP. Urinary NT-proBNP was normalized to urinary creatinine. Follow-up was performed after 45 months. Heart rhythm history was evaluated and a 12-lead electrocardiogram was performed at enrollment (sinus rhythm (SR, n = 306), atrial fibrillation (AFib, n = 79)). Results Patients suffering from atrial fibrillation showed significant higher age, reduced left ventricular ejection fraction (LVEF), higher rates of chronic kidney disease, hypertension and urinary as well as plasmatic NT-proBNP compared to patients with sinus rhythm (each p &amp;lt; 0.05). There were no differences regarding Diabetes, primary prevention ICD indication, coronary artery disease and dilatative cardiomyopathy (each p = n.s.). In ROC analysis, plasmatic NT-proBNP showed promising predictive values regarding AFib (AUC: 0.80, IQR 0.76-0.85, p &amp;lt; 0.001) as well as urinary NT-proBNP (AUC: 0.76, IQR 0.71-0.81, p &amp;lt; 0.001). There was no significant difference between plasmatic and urinary NT-proBNP according to ROC analysis (p = n.s.). Plasmatic NT-proBNP was shown as a significant predictor regarding existence of atrial fibrillation in binary logistic regression analysis, beside age (p &amp;lt; 0.05). Diabetes, hypertension, serum creatinine, LVEF, coronary artery disease and primary prevention ICD indication were no significant predictors (p = n.s.). Urinary NT-proBNP was not shown as a significant predictor regarding existence of atrial fibrillation in binary logistic regression analysis (p = n.s.). Conclusion Elevated levels of plasmatic NT-proBNP are strongly associated with the prevalence of atrial fibrillation in a cohort of ICD patients.

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.

Long QT syndrome: importance of reassessing arrhythmic risk after treatment initiation.

Risk scores are proposed for genetic arrhythmias. Having proposed in 2010 one such score (M-FACT) for the long QT syndrome (LQTS), this study aims to test whether adherence to its suggestions would be appropriate. LQT1/2/3 and genotype-negative patients without aborted cardiac arrest (ACA) before diagnosis or cardiac events (CEs) below age 1 were included in the study, focusing on an M-FACT score ≥2 (intermediate/high risk), either at presentation (static) or during follow-up (dynamic), previously associated with 40% risk of implantable cardioverter defibrillator (ICD) shocks within 4 years. Overall, 946 patients (26 ± 19 years at diagnosis, 51% female) were included. Beta-blocker (βB) therapy in 94% of them reduced the rate of those with a QTc ≥500 ms from 18% to 12% (P < .001). During 7 ± 6 years of follow-up, none died; 4% had CEs, including 0.4% with ACA. A static M-FACT ≥2 was present in 110 patients, of whom 106 received βBs. In 49/106 patients with persistent dynamic M-FACT ≥2, further therapeutic optimization (left cardiac sympathetic denervation in 55%, mexiletine in 31%, and ICD at 27%) resulted in just 7 (14%) patients with CEs (no ACA), with no CEs in the remaining 57. Additionally, 32 patients developed a dynamic M-FACT ≥2 but, after therapeutic optimization, only 3 (9%) had CEs. According to an M-FACT score ≥2, a total of 142 patients should have received an ICD, but only 22/142 (15%) were implanted, with shocks reported in 3. Beta-blockers often shorten QTc, thus changing risk scores and ICD indications for primary prevention. Yearly risk reassessment with therapy optimization leads to fewer ICD implants (3%) without increasing life-threatening events.

WEARABLE CARDIOVERTER–DEFIBRILLATORS IN CLINICAL PRACTICE IMPLEMENTATION OF THE ANMCO POSITION PAPER FOR APPROPRIATE USE OF THE WEARABLE CARDIOVERTER DEFIBRILLATOR

Abstract Introduction Wearable cardioverter–defibrillators (WCD) have emerged as a valuable tool in the management of patients at risk for life–threatening arrhythmias. These devices offer a non–invasive and temporary solution, providing continuous monitoring and the potential for prompt defibrillation when needed. In this study, we explore the indications for WCD and evaluate arrhythmic events through comprehensive monitoring. Methods From November 2022 to December 2023, we conducted an outpatient follow–up of 18 patients receiving WCD. Regular check–ups and comprehensive echocardiography were performed to optimize therapy based on specific indications for each patient. Results The average age of the patients was 59.3±17.4 years, with 79% being male. Among the cohort, 58% had hypertension, and a similar percentage comprised smokers and individuals with dyslipidemia, while 32% were diabetic. The indications for receiving WCD were: de novo diagnosis of dilated cardiomyopathy with reduced ejection fraction in 9 (50%) patients, recent acute coronary syndrome and ejection fraction &amp;lt; 35% in 5 (28%), cardiac electronic device infections in 3 (17%) patients and myocarditis with electrical instability in 1 (5%) patient. Patients were in optimal medical therapy (OMT) tailored to their specific comorbidities, with 84% on renin–angiotensin–aldosterone system inhibitors, 95% on beta–blockers, 53% on mineralocorticoid receptor antagonists, 53% on sodium–glucose cotransporter–2 inhibitors, and 37% on antiarrhythmics. The average follow–up was 64±45 days according to specific etiology, with a daily wearing time of 22.9±1.1 hours. No device interventions were recorded. At the end of the follow–up period, 6 (33%) patients still required implantable cardioverter–defibrillator (ICD). Among these, 4 patients (22%) underwent to ICD implantation, 3 for secondary prevention, and 1 for primary prevention, while notably, 2 (11%) patients, declined the procedure. Conclusions The use of wearable cardioverter–defibrillators in the outpatient setting for patients at risk of life–threatening arrhythmias allowed to optimize therapy and restrict the indications for ICD, in our cohort up to 67%, with a good safety profile due to the low incidence of device interventions.

Multicenter prospective observational study to clarify the current status and clinical outcome in Japanese patients who have an indication for implantable cardioverter defibrillator (ICD) or wearable cardioverter defibrillator (WCD) (TRANSITION JAPAN‐ICD/WCD study): Rationale and design of a prospective, multicenter, observational, comparative study

AbstractBackgroundDespite the positive impact of implantable cardioverter defibrillators (ICDs) and wearable cardioverter defibrillators (WCDs) on prognosis, their implantation is often withheld especially in Japanese heart failure patients with reduced left ventricular ejection fraction (HFrEF) who have not experienced ventricular tachycardia (VT) or ventricular fibrillation (VF) for uncertain reasons. Recent advancements in heart failure (HF) medications have significantly improved the prognosis for HFrEF. Given this context, a critical reassessment of the treatment and prognosis of ICDs and WCDs is essential, as it has the potential to reshape awareness and treatment strategies for these patients.MethodsWe are initiating a prospective multicenter observational study for HFrEF patients eligible for ICD in primary and secondary prevention, and WCD, regardless of device use, including all consenting patients. Study subjects are to be enrolled from 31 participant hospitals located throughout Japan from April 1, 2023, to December 31, 2024, and each will be followed up for 1 year or more. The planned sample size is 651 cases. The primary endpoint is the rate of cardiac implantable electronic device implementation. Other endpoints include the incidence of VT/VF and sudden death, all‐cause mortality, and HF hospitalization, other events. We will collect clinical background information plus each patient's symptoms, Clinical Frailty Scale score, laboratory test results, echocardiographic and electrocardiographic parameters, and serial changes will also be secondary endpoints.ResultsNot applicable.ConclusionThis study offers invaluable insights into understanding the role of ICD/WCD in Japanese HF patients in the new era of HF medication.

Regional disparities and risk factors of mortality among patients at high risk of sudden cardiac death in emerging countries: a nonrandomized controlled trial

BackgroundComprehensive data on patients at high risk of sudden cardiac death (SCD) in emerging countries are lacking. The aim was to deepen our understanding of the SCD phenotype and identify risk factors for death among patients at high risk of SCD in emerging countries.MethodsPatients who met the class I indication for implantable cardioverter-defibrillator (ICD) implantation according to guideline recommendations in 17 countries and regions underrepresented in previous trials were enrolled. Countries were stratified by the WHO regional classification. Patients were or were not implanted with an ICD at their discretion. The outcomes were all-cause mortality and SCD.ResultsWe enrolled 4222 patients, and 3889 patients were included in the analysis. The mean follow-up period was 21.6 ± 10.2 months. There were 433 (11.1%) instances of all-cause mortality and 117 (3.0%) cases of SCD. All-cause mortality was highest in primary prevention (PP) patients from Southeast Asia and secondary prevention (SP) patients from the Middle East and Africa. The SCD rates among PP and SP patients were both highest in South Asia. Multivariate Cox regression modelling demonstrated that in addition to the independent predictors identified in previous studies, both geographic region and ICD use were associated with all-cause mortality in patients with high SCD risk. Primary prophylactic ICD implantation was associated with a 36% (HR = 0.64, 95% CI 0.531–0.802, p < 0.0001) lower all-cause mortality risk and an 80% (HR = 0.20, 95% CI = 0.116–0.343, p < 0.0001) lower SCD risk.ConclusionsThere was significant heterogeneity among patients with high SCD risk in emerging countries. The influences of geographic regions on patient characteristics and outcomes were significant. Improvement in increasing ICD utilization and uptake of guideline-directed medical therapy in emerging countries is urgent.Trial registrationClinicalTrials.gov, NCT02099721.

Distinguishing Primary Prevention From Secondary Prevention Implantable Cardioverter Defibrillators Using Administrative Health and Cardiac Device Registry Data

BackgroundAdministrative health data and cardiac device registries can be used to empirically evaluate outcomes and costs after implantable cardioverter defibrillator (ICD) implantation. These datasets often have incomplete information on the indication for implantation (primary vs secondary prevention of sudden cardiac death). MethodsWe used 16 years of population-based cardiac device registry and administrative health data from British Columbia, Canada, to derive and internally validate statistical models that predict the likely indication for ICD implantation. We used chart review data as the reference standard for ICD indication in the Cardiac Device Registry database (CDR; 2004-2012 [Cardiac Services BC]) and nonmissing indication as the reference standard in the Heart Information System registry database (HEARTis; 2013-2019 [Cardiac Services BC]). We created 3 logistic regression prediction models in each database: one using only registry data, one using only administrative data, and one using both registry and administrative data. We assessed the predictive performance of each model using standard metrics after optimism correction with 200 bootstrap resamples. ResultsModels that used registry data alone demonstrated excellent predictive performance (sensitivity ≥ 89%; specificity ≥ 87%). Models that used only administrative data performed well (sensitivity ≥ 84%; specificity ≥ 70%). Models that used both registry and administrative data showed modest gains over those that used registry data alone (sensitivity ≥ 90%; specificity ≥ 89%). ConclusionsAdministrative health data and cardiac device registry data can distinguish secondary prevention ICDs from primary prevention ICDs with acceptable sensitivity and specificity. Imputation of missing ICD indication might make these data resources more useful for research and health system monitoring.

Are We Implanting Too Many Primary-Prevention Implantable Cardioverter-Defibrillators?

Canadian Cardiovascular Society/Canadian Heart Failure Society guidelines recommend optimizing patients with heart failure with reduced ejection fraction (HFrEF) on guideline directed medical therapy (GDMT) prior to implanting primary prevention implantable cardioverter defibrillators (ICDs). However, often GDMT is suboptimal at the time of ICD implantation, and is associated with reduced survival. Furthermore, with evidence for declining sudden cardiac death (SCD) rates in patients with cardiomyopathy, there is a need for better risk stratification to determine the indication for ICD.1 This raises concern for potentially unnecessary ICD implantation in this population, and efforts are needed to address this issue in clinical practice.

Expanded application of wearable cardioverter defibrillators beyond current guidelines: proposal for a European register explained through single clinical scenarios

The wearable cardioverter defibrillator (WCD) is becoming a more and more widely used instrument for the prevention of sudden cardiac death of patients either with a secondary prevention implantable cardioverter...

The Role of the Wearable Defibrillator in Heart Failure.

Wearable cardioverter defibrillators (WCDs) have been developed as a temporary measure for protecting patients at risk for sudden cardiac death that do not meet the indication for implantable cardioverter defibrillator (ICD), most notably in the early stages of heart failure with reduced ejection fraction before reassessment of their left ventricular ejection fraction. In this review, we report available evidence in the literature and guidelines regarding WCD use in order to try to define the role WCDs may have in heart failure. In the last decade, most observational studies found WCDs to be both safe and effective in terminating ventricular arrhythmias in various indications, mostly centered around heart failure with reduced ejection fraction. The only available randomized controlled trial using WCD did not however show a benefit on patients' survival. Hence, recent guidelines only recommended its use in limited indications. Recent data also suggest a possible interest of WCD in monitoring patients, a finding that may prove useful in the context of new-onset heart failure. Data regarding WCD benefit is scarce, and definitive conclusions on its utility are hard to draw. In the context of heart failure, and particularly new-onset heart failure, WCD might find a role in a global comprehensive management of the disease, both acting as an educational tool, a monitoring tool, and, most importantly, a safe and effective tool in preventing sudden cardiac death. The low level of evidence however invites caution, and the decision of prescribing a WCD needs to be individualized and thoroughly discussed with the patient whose compliance is key with this device.