Primary Prevention Of Sudden Cardiac Death Research Articles

Whether to implant a defibrillator or not? The Possibility of Using the MADIT-ICD Benefit Score Calculator in Real Practice

To study the predictive capabilities of the MADIT-ICD Benefit Score calculator in assessing the benefit of implantable cardioverter defibrillator (ICD) placement for the primary prevention of sudden cardiac death (SCD). This study included 388 patients with NYHA II-IV functional class chronic heart failure (CHF) with a left ventricular ejection fraction (LVEF) ≤35 % who underwent ICD placement for the primary prevention of SCD. Patients were followed up for two years to record the endpoints of first-time paroxysmal sustained ventricular tachyarrhythmia (VT) or non-arrhythmic death. According to the results of calculation with the MADIT-ICD Benefit Score calculator, 276 (71 %) patients had a high risk of VT (score ≥7) and 150 (39 %) had a high risk of non-arrhythmic death (score ≥3). 336 (94%) patients would benefit from an ICD: 148 (38 %) with a high level of probability and 218 (56 %) with a medium level of probability. According to the incidence of endpoints, VT episodes predominated in the low-ICD benefit group (36%), while the high-ICD benefit group had a relatively high incidence of non-arrhythmic death (12%). The results obtained for a cohort of Russian patients with CHF and reduced LVEF indicated that the use of the MADIT-ICD Benefit Score in routine clinical practice does not improve the stratification of SCD risk compared to the traditional approach to selecting patients with CHF for ICD based on the LVEF value.

Detection of gene mutation in the prognosis of a patient with arrhythmogenic right ventricular cardiomyopathy: a case report

BackgroundArrhythmogenic right ventricular cardiomyopathy (ARVC), or more recently known as arrhythmogenic cardiomyopathy (ACM), is an heritable disorder of the myocardium characterized by progressive fibrofatty replacement the heart muscle and risk of ventricular arrhythmias and sudden cardiac death (SCD). We report a case study to demonstrate the role of gene mutation detection in risk stratification for primary prevention of SCD in a young patient diagnosed with ARVC.Case presentationA 15-year-old Asian (Vietnamese) male patient with no history of documented tachyarrhythmia or syncope and a family history of potential SCD was admitted due to palpitations. Clinical findings and work-up including cardiac magnetic resonance imaging (MRI) were highly suggestive of ARVC. Gene sequencing was performed for SCD risk stratification, during which PKP2 gene mutation was found. Based on the individualized risk stratification, an ICD was implanted for primary prevention of SCD. At 6 months post ICD implantation, the device detected and successfully delivered an appropriate shock to terminate an episode of potentially fatal ventricular arrhythmia. ICD implantation was therefore proven to be appropriate in this patient.ConclusionsWhile gene mutations are known to be an important factor in the diagnosis of ARVC according to the 2010 Task Force Criteria and recent clinical guidelines, their role in risk stratification of SCD remains controversial. Our case demonstrated that when used with other clinical factors and family history, this information could be helpful in identifying appropriate indication for ICD implantation.

Clinical and genetic characterization of patients with catecholaminergic polymorphic ventricular tachycardia: a case series

AIM: of the study was to evaluate the clinical and genetic characteristics, including the development of adverse events and outcomes in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT).
 MATERIALS AND METHODS: The clinical phenotype of eight patients with CPVT, two of whom were relatives of probands, was observed over 4 years. The clinical and instrumental study included ECG-12, 24-hour Holter ECG monitoring, genealogical history collection and family history of sudden cardiac death (SCD), transthoracic echocardiography and cardiac magnetic resonance imaging to detect structural myocardial changes, electrophysiologic study according to indications, and ICD monitoring. High-throughput sequencing (NGS) was utilized to search for mutations in genes linked to the onset of channelopathies and other inherited rhythm disorders.
 RESULTS: In 8 patients, nucleotide variants of pathogenicity classes III-V were identified according to the ACMG (2015) criteria in the RYR2 gene associated with CPVT. Pathogenic (IV-V class) and likely pathogenic (IV class) mutations in the RYR2 gene were found in 6 (75%) probands, variants with uncertain clinical significance (VUS, class III) were found in 2 patients. At the time of diagnosis, transient QTc interval prolongation of more than 480 ms was detected in 4 (50%) patients; bradycardia less than 54 beats/min — in 2 (25%) patients, sequences of supraventricular tachycardia and ventricular tachyarrhythmia — in 2 (25%) patients. The most severe form of the disease with marked clinical manifestations and an episode of clinical death with subsequent resuscitation, as well as a transient QTc interval prolongation exceeding 500 ms was observed in patients with mutations c.11814C A (p.Ser3938Arg, rs794728704); c.463G A (p.Gly155Arg) and c.14876G A (p.Arg4959Gln, rs794728811) in the RYR2 gene. Three (37.5%) patients underwent ICD implantation; one for primary SCD prevention and two for secondary prevention.
 CONCLUSION: In this study, the spectrum of clinical manifestations in patients with genetically confirmed CPVT was examined. The findings highlight transient QTc interval extensions, significant sinus bradycardia, and sequences of supraventricular tachyarrhythmias, which can escalate into life-threatening ventricular tachyarrhythmias in CPVT patients.

Abstract 16010: Sudden Death in the Systemic Right Ventricle: Single Center Study of Dextro-Transposition of the Great Arteries Palliated With Atrial Switch

Introduction: The incidence and risk factors for sudden cardiac death (SCD) in patients with systemic right ventricle (sRV) and D-TGA palliated with atrial switch procedures is not well understood. Methods: This cohort was examined retrospectively for the composite end point of SCD, sustained ventricular tachycardia (VT) >30 s or appropriate ICD therapy for VT. Clinical characteristics of those with and without the end point were compared using the Kruskal-Wallis or Chi-square test as appropriate. Results: The composite end point occurred in 15 of 148 (10%) patients (63.5% male) at a mean age of 36.4 (SD 10.3) years. SCD occurred in 6 patients (n=2 successfully resuscitated), sustained VT in 6 patients and ICD therapy for VT in 3 patients who had previously received a primary prevention ICD. Patients with SCD/VT had lower sRV ejection fraction (EF) compared to patients without SCD/VT [28±11 vs 40±10%, P<0.001]. The odds ratio of SCD/VT in patients with sRVEF≤35% compared to sRVEF>35% was 13.3 (95% CI 2.8 - 64.4). Kaplan Meier analysis of time to SCD/VT stratified by sRV EF is presented in figure. QRS duration, QRS fragmentation, QTc and history of systemic AV valve surgery were not significantly associated with SCD/VT. Non-sustained ventricular tachycardia (NSVT) on Holter monitoring occurred more frequently in SCD/VT patients (80 vs 39%, p=0.003). All 11 survivors of SCD/VT received an ICD; appropriate ICD therapy occurred in 27% of these patients during follow-up. Conclusion: SCD or VT occurred in one-tenth of D-TGA patients palliated with atrial switch, predominantly in 3 rd and 4 th decade of life. Reduced sRV EF was the most important association and ICD implantation for primary prevention of SCD is a reasonable consideration in those with reduced sRV EF.

Abstract 17896: Implantable Cardioverter Defibrillator in Cardiac Resynchronization Therapy Recipients With Advanced Chronic Kidney Disease

Introduction: The effectiveness of the implantable cardioverter defibrillator (ICD) in preventing sudden cardiac death (SCD) is well-established in heart failure patients with reduced ejection fraction (HFrEF). However, the benefit of the ICD in advanced chronic kidney disease (CKD) patients remains elusive, particularly in those who are cardiac resynchronization therapy (CRT) recipients. Hypothesis: In CRT recipients with CKD, the benefit of the ICD may be attenuated due to the competing risk of mortality before experiencing an arrhythmia. Methods: A total of 1015 patients receiving CRT with defibrillator (CRT-D) for primary prevention of SCD were included from the MADIT-CRT and RAID trials. Patients were categorized into two groups based on kidney disease (KD) stage: Stage 1-3a (S1-S3a) CKD and Stage 3b-5 (S3b-S5) CKD. The primary endpoint was the occurrence of ventricular tachycardia (VT) or ventricular fibrillation (VF). Results: The cumulative incidence of any VT/VF was 23.5% in patients with (S1-S3a)KD and 12.6% in those with (S3b-S5)KD (p<0.001 [Figure left panel]). Death without VT/VF occurred in 6.6% of patients with (S1-S3a)KD and 21.6% of patients with( S3b-S5)KD (p<0.001 [Figure right panel]). A multivariate competing risk regression model revealed that patients with (S3b-S5)KD had a 43% lower risk of experiencing any VT/VF compared to those with (S1-S3a)KD (HR=0.56, 95% CI [0.33-0.94], p=0.03). Over two years of follow-up, patients with (S3b-S5)KD had nearly a five-fold increased risk of death without VT/VF compared to those with (S1-S3a)KD (HR=4.63, 95% CI [2.46-8.72], p for interaction with time=0.012). Conclusions: The benefit of the ICD may be attenuated in CRT recipients with advanced CKD due to a lower incidence of arrhythmias and a higher risk of non-arrhythmic death. Future prospective trials should investigate whether CRT without a defibrillator is more suitable for these patients.

Revascularization and Left Ventricular Dysfunction for ICD Eligibility.

Common triggers for sudden cardiac death (SCD) are transient ischemia, hemodynamic fluctuations, neurocardiovascular influences, and environmental factors. SCD occurs rapidly when sinus rhythm degenerates into ventricular tachycardia (VT) and/or ventricular fibrillation (VF), followed by asystole. Such progressive worsening of the cardiac rhythm is in most cases observed in the setting of ischemic heart disease and often associated with advanced left ventricular (LV) impairment. Revascularization prevents negative outcomes including SCD and heart failure (HF) due to LV dysfunction (LVD). The implantable cardioverter-defibrillator (ICD) on top of medical therapy is superior to antiarrhythmic drugs for patients with LVD and VT/VF. The beneficial effects of ICD have been demonstrated in primary prevention of SCD as well. However, yet debated is the temporal management for patients with LVD who are eligible to ICD prior to revascularization, either through percutaneous or surgical approach. Restoration of coronary blood flow has a dramatic impact on adverse LV remodeling, while it requires aggressive long-term antiplatelet therapy, which might increase complication for eventual ICD procedure when percutaneous strategy is pursued; on the other hand, when LV and/or multiorgan dysfunction is present and coronary artery bypass grafting is chosen, the overall risk is augmented, mostly in HF patients. The aims of this review are to describe the pathophysiologic benefits of revascularization, the studies addressing percutaneous, surgical or no revascularization and ICD implantation, as well as emerging defibrillation strategies for patients deemed at transient risk of SCD and/or at higher risk for transvenous ICD implantation.

Primary prevention implantable cardioverter defibrillator in cardiac resynchronization therapy recipients with advanced chronic kidney disease.

The implantable cardioverter defibrillator (ICD) is effective for the prevention of sudden cardiac death (SCD) in patients with heart failure and a reduced ejection fraction (HFrEF). The benefit of the ICD in patients with advanced CKD, remains elusive. Moreover, the benefit of the ICD in patients with advanced chronic kidney disease (CKD) and HFrEF who are cardiac resynchronization therapy (CRT) recipients may be attenuated. We hypothesized that patients with CKD who are CRT recipients may derive less benefit from the ICD due to the competing risk of dying prior to experiencing an arrhythmia. The study population included 1,015 patients receiving CRT with defibrillator (CRT-D) device for primary prevention of SCD who were enrolled in either (Multicenter Automated Defibrillator Implantation Trial) MADIT-CRT trial or the Ranolazine in High-Risk Patients with Implanted Cardioverter Defibrillator (RAID) trial. The cohort was divided into two groups based on the stage of CKD: those with Stage 1 to 3a KD, labeled as (S1-S3a)KD. The second group included patients with Stage 3b to stage 5 kidney disease, labeled as (S3b-S5)KD. The primary endpoint was any ventricular tachycardia (VT) or ventricular fibrillation (VF) (Any VT/VF). The cumulative incidence of Any VT/VF was 23.5% in patients with (S1-S3a)KD and 12.6% in those with (S3b-S5)KD (p < 0.001) The incidence of Death without Any VT/VF was 6.6% in patients with (S1-S3a)KD and 21.6% in patients with (S3b-S5)KD (p < 0.001). A Fine and Gray multivariate competing risk regression model showed that Patients with (S3b-S5)KD had a 43% less risk of experiencing Any VT/VF when compared to those with (S1-S3a)KD (HR = 0.56, 95% CI [0.33-0.94] p = 0.03. After two years of follow up, there was almost a 5-fold increased risk of Death without Any VT/VF among patients with (S3b-S5)KD when compared to those with (S1-S3a)KD [HR = 4.63, 95% CI (2.46-8.72), p for interaction with time = 0.012]. Due to their lower incidence of arrhythmias and higher risk of dying prior to experiencing an arrhythmia, the benefit of the ICD may be attenuated in CRT recipients with advanced CKD. Future prospective trials should evaluate whether CRT without a defibrillator may be more appropriate for these patients.

Sudden Cardiac Death: A Systematic Review.

Sudden cardiac death (SCD) is a condition that accounts for a high percentage of cardiovascular fatalities, with ventricular tachyarrhythmias being the most common cause. There are signs and symptoms of SCD that occur spontaneously without any warning and are deadly. Despite preventative efforts focusing on the use of subcutaneous implanted cardioverter defibrillators (S-ICD) in the highest-risk population categories, a high number of SCDs occur in the normal population and in people who do not have a documented cardiac condition. Therefore, primary prevention for SCD should be a more viable strategy for the general population, considering measures in the form of preventive medicine such as knowing more about any genetic predisposition, family history of any fatal arrhythmia, continuous surveillance after any syncope with unknown causes, etc. However, little data about SCD risk factors are known in comparison with other well-known diseases like ischemic heart disease and stroke.In search of medical databases for relevant medical literature, we looked at PubMed/Medline, the Cochrane Library, and Google Scholar. Thirteen publications were discovered after the papers were located, assessed, and qualifying criteria were applied. The finished articles were done to give an overview of SCD. Some others have shown that the major predisposition for SCD is related to the male gender, which increases the incidence if they have a family history of SCD. We described the importance of obstructive sleep apnea (OSA) as a comorbid condition. Patients with S-ICD and young athletes with a history of ventricular arrhythmia showed us that the predisposition for SCD can be higher than in the normal population. Based on the above, we concluded that more study is required to establish the most important approach for eachof the risk factors mentioned in this systematic review in order to apply them in daily practice and have more knowledge about how to apply preventive and therapeutic medicine to the population at risk and the ones that already develop the disease.

Improved patient selection for primary prevention ICD implantation by predicting ICD non-benefit using artificial intelligence

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): NWO Rubicon (452019308) Amsterdam Cardiovascular Sciences Background Left Ventricular Ejection Fraction (LVEF) is suboptimal as a sole marker for predicting sudden cardiac death (SCD) or benefit from an ICD. Machine (ML) and deep (DL) learning provide new opportunities for personalised predictions using complex, multi-modal physiological data. Objective We hypothesise that risk stratification for ICD implantation can be improved by ML and DL models that combine clinical variables with time series features from 12-lead electrocardiograms (ECG). Methods We present a multicentre study of 1010 patients with an ischaemic, dilated or non-ischaemic cardiomyopathy and LVEF≤35% implanted with an ICD between 2007 and 2021 for primary prevention of SCD (64.9 ±10.8 years, 73.2% male) in two academic hospitals. For each patient, raw 12-lead, 10-second ECG-recordings obtained &amp;lt;90 days before ICD implantation and clinical details were collected. Supervised ML and DL models were trained and validated using stratified k-fold cross-validation (5 repeats, k=10) on a development cohort (n=550) from Hospital A. We used this model to predict ICD non-benefit defined as mortality without prior appropriate ICD-therapy on an external dataset from Hospital B (n=460). Kaplan-Meier survival analysis stratified by high vs. low predicted probability using Youden's J statistic as cut-off was performed. Results At 3-year follow-up, 16.0% of patients had died of whom 72.8% met the criteria for ICD non-benefit. Extreme gradient boosting models identified subjects with ICD non-benefit with an area under the receiver operator curve (AUROC) of 0.897 ±0.05 during internal validation (Figure 1, solid line). In the external cohort, the AUROC was 0.793 (95% CI 0.75-0.84) (Figure 1, dashed line). Survival analysis for low vs. high predicted risk indicated ICD non-benefit rates of 6.0% versus 30.3% at 3-year follow-up, respectively (Figure 2). Conclusion A ML model that combined clinical with ECG features better predicted ICD non-benefit at 3-years in a primary prevention population than currently available risk scores such as the MADIT-ICD score. This approach may provide new tools to support personalized decision making for ICD therapy. Prospective validation is needed to assess the real-world clinical performance of the model.

The Role of Electrophysiological Study in the Risk Stratification of Brugada Syndrome.

Brugada syndrome (BrS) is a complex arrhythmogenic disease associated with an increased risk of sudden cardiac death (SCD). The role of electrophysiological study (EPS) for risk stratification purposes of asymptomatic BrS patients remains still controversial. This study aims to summarize the existing data about the role of electrophysiological study for arrhythmic risk stratification of BrS patients without a prior history of aborted SCD or fatal arrhythmic event. Two independent investigators (G.B. and G.T.) performed a systematic search in the MedLine database and Cochrane library from their inception until April 2022 without any limitations. The reference lists of the relevant research studies as well as the relevant review studies and meta-analyses were manually searched. Nineteen studies were included in the final analysis. The included studies enrolled 6218 BrS patients (mean age: 46.9 years old, males: 76%) while 4265 (68.6%) patients underwent an EPS. The quantitative synthesis showed that a positive EPS study was significantly associated with arrhythmic events in BrS patients (RR, 1.74 [1.23-2.45]; P = 0.002; I2 = 63%]. By including the studies that provided data on the association of EPS with arrhythmic events during follow-up in patients without a prior history of aborted SCD or fatal arrhythmic event, the association between positive EPS study and future arrhythmic events remained significant (RR, 1.60 [1.08-2.36]; P = 0.02; I2 = 19%). In conclusion, EPS is a useful invasive tool for the risk stratification of BrS patients and can be used to identify the population of BrS patients who may be candidates for primary prevention of SCD with implantable cardioverter-defibrillator (ICD) implantation.

Rare Case of Pediatric Hypertrophic Obstructive Cardiomyopathy (HOCM) in A 6-year-old Boy: How to Recognize, Assess, and Manage the Risk?

Highlights: It discusses pediatric HCM which is usually caused by autosomal dominant traits caused by mutation in cardiac sarcomere protein genes. It explains how to recognize the cardiac risk Abstract: Hypertrophic Obstructive Cardiomyopathy (HOCM) is a disease characterized by increased left ventricular (LV) wall thickness and accompanied by obstructive physiology measured by increased LV outflow tract gradient. It is mainly inherited in autosomal dominant traits caused by a mutation in cardiac sarcomere protein genes. In pediatrics, HOCM is rare and comprises a different diagnosis and management approach compared to adults. The risk of sudden cardiac death (SCD) is also higher in the pediatric population. Case Summary. This report is about a case of HOCM found incidentally in a 6-year-old boy and a discussion based on the latest literature review. The patient first came for evaluation for cardiac murmur and abnormality in ECG and chest x-ray. Diagnosis of HOCM was made through echocardiography assessment. Discussion. ICD implantation for primary prevention of SCD was considered based on individualized 5-year SCD risk assessment which is around 7%. Optimal pharmacological therapy with beta-blocker, careful planning of ICD implantation with balanced benefit and risk, and septal reduction surgery when indicated should extend the life expectancy and quality of life of pediatric HOCM. It is both essential and interesting to recognize pediatric HOCM diagnostic findings and to pursue further research about therapies of this rare disease.

Primary sudden cardiac death prevention in hypertrophic cardiomyopathy resulted from LEOPARD Syndrome

Leopard syndrome is an autosomal dominant inherited disease manifested by numerous cutaneous birthmarks, heart electrical conduction disorders, hypertelorism, pulmonary valve stenosis, deafness and hypertrophic cardiomyopathy. The disease may be accompanied by symptomatic ventricular tachycardia. In patients without the need for cardiac pacing and indications for a cardioverter-defibrillator (ICD) implantation, a completely subcutaneous system (S-ICD) may become an efficient option.

Implantable cardioverter-defibrillators for primary and secondary prevention of sudden cardiac death in clinical practice: analysis of the clinical and anamnestic characteristics of patients according to the Kuzbass registry

Aim. To study clinical and anamnestic data of patients with implantable cardioverterdefibrillators (ICD) for primary or secondary prevention of sudden cardiac death (SCD) based on the data from the Kuzbass ICD registry.Methods. Retrospective analysis of demographic, clinical and anamnestic data from the “Kuzbass Registry of Patients with Implanted Cardioverter-Defibrillator”, which includes 286 patients admitted at the Kuzbass Cardiology Center in 2015–2019, was carried out.Results. The age of patients included in the registry was 59 (53; 66) years, 239 (83.6%) were men; all patients were diagnosed with heart failure. ICD for primary prevention of SCD was prescribed in 171 (63.6%) patients (group 1) and for secondary prevention in 98 (36.4%) patients (group 2). The groups were comparable in age, sex, main nosology (coronary artery disease), left ventricular ejection fraction (31.4 (26; 35) and 30 (10; 68)%, p = 0.389). Compared with the group 2, the group 1 had fewer working patients, higher incidence of heart defects, severe heart failure, higher incidence of paroxysmal supraventricular tachycardia (68.7% versus 44.8%, p = 0.001), and higher rates of revascularization (48, 9% and 31.7%, respectively, p = 0.006). Before ICD implantation for heart failure, 210 (73.4%) patients were receiving renin angiotensin aldosterone system inhibitors, 259 (90.6%) – beta-blockers, 167 (58.4%) – mineralocorticoid receptor antagonists. There were no differences in prescribed treatment between the groups. Only 137 (47.9%) patients, 86 (47.3%) patients in the group 1 and 51 (49.0%) patients in the group 2 received triple neurohormonal blockade. Remote monitoring was used only within the framework of research programs.Conclusion. The primary cohort of patients with ICD is the primary SCD prevention group. Regardless of the type of SCD prevention, the underlying disease is coronary artery disease. Current guidelines for optimal drug therapy and myocardial revascularization are not always followed prior to ICD implantation. The creation of registries of patients with ICD is an effective way to identify existing problems in ICD patient selection and to optimize follow-up and treatment.

Abstract 11307: Longer Outflow Tract Conduction Time by Magnetocardiography as a Novel Non-Invasive Maker for Predicting Lethal Events in Patients With Brugada Syndrome Without Ventricular Fibrillation

Introduction: Many of the Brugada syndrome (BrS) patients have no symptom or only syncope without ventricular fibrillation (VF)/sudden cardiac death (SCD), thus to whom we should recommend implantable cardioverter defibrillator (ICD) for primary prevention of SCD is still the biggest concern in the BrS. Here we investigated whether a high spatial resolution magnetocardiography (MCG) could predict lethal events of the BrS without history of VF/SCD. Methods: This study retrospectively enrolled 157 BrS patients without VF or cardiopulmonary arrest (CPA) (150 male, 42±13 years old, 118 spontaneous and 39 drug-induced type-1 ECG). Outflow tract conduction time (OT-CT) from 2-D current map of MCG was measured in all patients as well as the standard 12-lead ECG and signal-averaged ECG (SAECG). Programmed electrical stimulation (PES) for VF induction was performed in 47 patients. Results: Patients with spontaneous type-1 ECG had longer OT-CT compared with type-2 BrS patients. Na channel blocker, pilsicainide (25-50mg) unmasked type-1 ECG as well as increased OT-CT (54±18 to 127±62 ms; p&lt;0.05), whereas additional isoproterenol (1ug/kg/min) reversed the pilsicainide-induced delayed OT-CT, thus normalized the ST elevation of ECG. During follow-up (mean 72 [6-147] months), 10 (6%) patients suffered VF/CPA, and those had a higher incidence of previous syncope (50% vs. 14.4%, p=0.01) and longer baseline OT-CT (83±31ms vs. 55±24ms, p=0.01) compared with event-free patients. Receiver operating curve (ROC) revealed OT-CT=65ms was a cut-off value of VF/CPA (AUC=0.78), whereas, spontaneous type-1 ECG, late potential of SAECG, family history, and VF inducibility by PES were not associated with VF/CPA events during follow-up. Multivariate Cox proportional analysis revealed that previous syncope (HR=1.70, 95%CI:1.01-3.05, p=0.04) and OT-CT≥65ms (HR=1.72, 95%CI=1.16-2.62) were the independent predictor for lethal events in the BrS without VF/CPA. Among asymptomatic BrS patients (n=131), OT-CT≥65ms was also an independent predictor for VF/CPA (HR=1.69, 95%CI=1.04-2.79, p=0.03). Conclusion: Longer OT-CT in the MCG may noninvasively demonstrate substrate of VF in BrS and stratify the risk of lethal events in patients with BrS without history of VF or CPA.

Utilization and in-hospital complications associated with implantation of dual versus single chamber implantable cardioverter defibrillator for primary prevention of sudden cardiac death

Abstract Introduction Multiple studies showed no clinical benefit in implantation of a dual compared to a single chamber implantable cardioverter defibrillator (dICD vs. sICD) for primary prevention of sudden cardiac death (SCD), in patients with no pacing indication. We aimed to investigate the extent of utilization and complications in sICD vs. dICD implantations in the US, using the National In-Patient Sample (NIS) database. Methods Using the NIS database, we identified patients who underwent an elective ICD implantation in the US between 2015 (last quarter)-2019. Patients who had concurrent conduction disorders or indication for atrial pacing were excluded. Baseline demographics, clinical characteristics, cardiomyopathy etiologies as well as outcomes including in-hospital complications, length of stay and mortality were collected. Multivariable logistic regression models were used to identify predictors of complications. Results and discussion An estimated total of 15940 patients, who underwent elective ICD implantation for primary prevention of SCD were identified, 8860 (55.6%) of them received a dICD. Forty percent of patients had ischemic cardiomyopathy. The mean age was 64 years and 66% were males. The complication rates documented in the dICD and sICD groups were 13% and 11%, respectively (p&amp;lt;0.001),driven by increased rate of pneumothorax (4.8% vs 3.2%, p&amp;lt;0.001) and lead dislodgement (3.6% vs 2.3%, p&amp;lt;0.001, Table 1). Multivariate analysis confirmed adding an atrial lead as an independent risk factor for “any complication” during ICD implantation [OR 1.13 (1.02–1.25), p=0.022] as well as for pneumo/hemothorax [OR 1.21 (1.03–1.44), p=0.025] and lead dislodgement [OR 1.41 (1.16–1.72), p&amp;lt;0.001]. Conclusion Despite significant evidence for lack of clinical benefit in adding an atrial lead to a primary prevention ICD implantation, significant proportion of the patients in the US are implanted with a dICD. We show increased risk for complications for dICD compared with sICD implantation in the US in recent years, driven by higher incidence of pneumo/hemothorax and lead dislodgement. Funding Acknowledgement Type of funding sources: None.

Late gadolinium enhancement is a strong predictor of life threatening arrhythmias in patients with dilated cardiomyopathy undergoing ICD implantation for primary prevention of sudden cardiac death

Abstract Background The usefulness of implantable cardioverter defibrillators (ICD) for primary prevention of arrhythmic sudden cardiac death (SCD) in patients with non-ischemic dilated cardiomyopathy (DCM) has been questioned. Efforts to improve risk stratification have included scores such as the “MADIT-ICD benefit score”, and the use of late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR). The purpose of this study was to evaluate the potential usefulness of these two tools to assess the risk of life-threatening arrhythmias in patients with non-ischemic DCM undergoing ICD implantation for primary prevention of SCD. Methods We conducted a single-center retrospective study of consecutive patients who underwent contrast-enhanced CMR before ICD implantation for primary prevention of SCD. Patients with ischemic cardiomyopathy were used as reference. Patients with non-dilated cardiomyopathies were excluded. The arrhythmic component of the MADIT-ICD benefit score (VT/VF score) was calculated for each patient, and considered high if ≥7, as recommended. The primary endpoint was the occurrence of SCD or life-threatening arrhythmias (VF or VT &amp;gt;200 bpm). Follow-up was performed by device interrogation in all patients except those who suffered SCD. Results A total of 151 patients (93 ischemic, mean age 62±13 years, 75% male) with mean left ventricular ejection fraction (LVEF) of 27±8% were included. Overall, 72% (n=67) ischemic and 45% (n=26) non-ischemic patients had scores ≥7 and were considered high-risk. LGE was present in all patients with ischemic cardiomyopathy, and in 76% (n=44) of patients with non-ischemic DCM. During a median follow-up of 21 (8–38) months, 21 patients (13.9%, 11 ischemic and 10 non-ischemic) met the primary endpoint. Overall, the event-free survival of non-ischemic patients was similar to that of ischemic patients (log rank p=0.269). In patients with non-ischemic DCM, there were 7 arrhythmic events (26.9%) in those with MADIT-ICD VT/VF scores ≥7, and 3 events (9.4%) in those with scores &amp;lt;7 (log rank p=0.104). In the same population, there were 10 arrhythmic events (23%) in patients with LGE, but no events in patients without LGE (log rank p=0.036). LVEF was similar in patients with and without arrhythmic events (26±8% vs. 27±7%, p=0.717), and in those with and without LGE (26±7% vs. 28±9%, p=0.342). Conclusion The presence of LGE is a strong predictor of life threatening arrhythmias in patients in non-ischemic DCM undergoing ICD implantation for primary prevention, seemingly outperforming the clinical MADIT-ICD benefit score. Funding Acknowledgement Type of funding sources: None.

Ventricular arrhythmia and sudden cardiac death in hypertrophic cardiomyopathy: From bench to bedside.

Patients with hypertrophic cardiomyopathy (HCM) mostly experience minimal symptoms throughout their lifetime, and some individuals have an increased risk of ventricular arrhythmias and sudden cardiac death (SCD). How to identify patients with a higher risk of ventricular arrythmias and SCD is the priority in HCM research. The American College of Cardiology/American Heart Association (ACC/AHA) and the European Society of Cardiology (ESC) both recommend the use of risk algorithms to identify patients at high risk of ventricular arrhythmias, to be selected for implantation of implantable cardioverters/defibrillators (ICDs) for primary prevention of SCD, although major discrepancies exist. The present SCD risk scoring systems cannot accurately identify early-stage HCM patients with modest structural remodeling and mild disease manifestations. Unfortunately, SCD events could occur in young asymptomatic HCM patients and even as initial symptoms, prompting the determination of new risk factors for SCD. This review summarizes the studies based on patients' surgical specimens, transgenic animals, and patient-derived induced pluripotent stem cells (hiPSCs) to explore the possible molecular mechanism of ventricular arrhythmia and SCD. Ion channel remodeling, Ca2+ homeostasis abnormalities, and increased myofilament Ca2+ sensitivity may contribute to changes in action potential duration (APD), reentry circuit formation, and trigger activities, such as early aferdepolarization (EAD) or delayed afterdepolarization (DAD), leading to ventricular arrhythmia in HCM. Besides the ICD implantation, novel drugs represented by the late sodium current channel inhibitor and myosin inhibitor also shed light on the prevention of HCM-related arrhythmias. The ideal prevention strategy of SCD in early-stage HCM patients needs to be combined with gene screening, hiPSC-CM testing, machine learning, and advanced ECG studies, thus achieving individualized SCD prevention.

Arrhythmic risk prediction in arrhythmogenic right ventricular cardiomyopathy: external validation of the arrhythmogenic right ventricular cardiomyopathy risk calculator.

AimsArrhythmogenic right ventricular cardiomyopathy (ARVC) causes ventricular arrhythmias (VAs) and sudden cardiac death (SCD). In 2019, a risk prediction model that estimates the 5-year risk of incident VAs in ARVC was developed (ARVCrisk.com). This study aimed to externally validate this prediction model in a large international multicentre cohort and to compare its performance with the risk factor approach recommended for implantable cardioverter-defibrillator (ICD) use by published guidelines and expert consensus.Methods and resultsIn a retrospective cohort of 429 individuals from 29 centres in North America and Europe, 103 (24%) experienced sustained VA during a median follow-up of 5.02 (2.05–7.90) years following diagnosis of ARVC. External validation yielded good discrimination [C-index of 0.70 (95% confidence interval-CI 0.65–0.75)] and calibration slope of 1.01 (95% CI 0.99–1.03). Compared with the three published consensus-based decision algorithms for ICD use in ARVC (Heart Rhythm Society consensus on arrhythmogenic cardiomyopathy, International Task Force consensus statement on the treatment of ARVC, and American Heart Association guidelines for VA and SCD), the risk calculator performed better with a superior net clinical benefit below risk threshold of 35%.ConclusionUsing a large independent cohort of patients, this study shows that the ARVC risk model provides good prognostic information and outperforms other published decision algorithms for ICD use. These findings support the use of the model to facilitate shared decision making regarding ICD implantation in the primary prevention of SCD in ARVC.

Predictors of primary prevention implantable cardioverter-defibrillator use in heart failure with reduced ejection fraction: impact of the predicted risk of sudden cardiac death and all-cause mortality.

AimsUse of implantable cardioverter‐defibrillators (ICD) for primary prevention of sudden cardiac death (SCD) in heart failure with reduced ejection fraction (HFrEF) is limited. We aimed to investigate barriers to ICD use in HFrEF while considering the predicted risk of mortality and SCD.Method and resultsPatients from the SwedeHF registered in 2011–2018 and with an indication for primary prevention ICD were analysed. The Seattle Proportional Risk and Seattle Heart Failure Models were used to predict the proportional SCD and all‐cause mortality risk, respectively. A multivariable logistic regression model was fitted to identify independent predictors of ICD use/non‐use; Cox regression models to evaluate the interaction between predicted SCD/mortality risk and ICD use for mortality. Of 13 475 patients, only 15.5% had an ICD. Those with higher predicted proportional SCD risk (>45%) had an ∼80% higher likelihood to have an ICD. Other predictors of non‐use were follow‐up in primary versus specialty care, higher comorbidity burden and lower socioeconomic status. ICD use was associated with lower mortality only in patients with higher predicted SCD and lower mortality risk (34% and 37% relative risk reduction for 3‐year all‐cause and cardiovascular mortality, respectively). In this subgroup of patients, underuse of ICD was 81.8%.ConclusionIn a contemporary registry, only 15.5% of patients with an indication for primary prevention ICD received the device. While a high predicted proportional SCD risk was appropriately linked to ICD use, the lack of specialized follow‐up, higher comorbidity burden, and lower socioeconomic status were major unjustified impediments to implementation. Our findings suggest areas for improving ICD use for primary prevention of SCD in clinical practice.

Late gadolinium enhancement is a strong predictor of life threatening arrhythmias in patients with non-ischemic dilated cardiomyopathy undergoing ICD implantation for primary prevention of sudden card

Abstract Funding Acknowledgements Type of funding sources: None. Background The usefulness of implantable cardioverter defibrillators (ICD) for primary prevention of arrhythmic sudden cardiac death (SCD) in patients with non-ischemic dilated cardiomyopathy (DCM) has been questioned. Efforts to improve risk stratification have included scores such as the ‘MADIT-ICD benefit score’, and the use of late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR). The purpose of this study was to evaluate the potential usefulness of these two tools to assess the risk of life-threatening arrhythmias in patients with non-ischemic DCM undergoing ICD implantation for primary prevention of SCD. Methods We conducted a single-center retrospective study of consecutive patients who underwent contrast-enhanced CMR before ICD implantation for primary prevention of SCD. Patients with ischemic cardiomyopathy were used as reference. Patients with non-dilated cardiomyopathies were excluded. The arrhythmic component of the MADIT-ICD benefit score (VT/VF score) was calculated for each patient, and considered high if ≥ 7, as recommended. The primary endpoint was the occurrence of SCD or life-threatening arrhythmias (VF or VT &amp;gt;200 bpm). Follow-up was performed by device interrogation in all patients except those who suffered SCD. Results A total of 151 patients (93 ischemic, mean age 62±13 years, 75% male) with mean left ventricular ejection fraction (LVEF) of 27±8% were included. Overall, 72% (n=67) ischemic and 45% (n=26) non-ischemic patients had scores ≥ 7 and were considered high-risk. LGE was present in all patients with ischemic cardiomyopathy, and in 76% (n=44) of patients with non-ischemic DCM. During a median follow-up of 21 (8-38) months, 21 patients (13.9%, 11 ischemic and 10 non-ischemic) met the primary endpoint. Overall, the event-free survival of non-ischemic patients was similar to that of ischemic patients (log rank p=0.269) – Fig 1A. In patients with non-ischemic DCM, there were 7 arrhythmic events (26.9%) in those with MADIT-ICD VT/VF scores ≥7, and 3 events (9.4%) in those with scores &amp;lt;7 (log rank p= 0.104) – Fig 1B. In the same population, there were 10 arrhythmic events (23%) in patients with LGE, but no events in patients without LGE (log rank p=0.036) – Fig 1C. LVEF was similar in patients with and without arrhythmic events (26±8% vs. 27±7%, p=0.717), and in those with and without LGE (26±7% vs. 28±9%, p=0.342). Conclusion The presence of LGE is a strong predictor of life threatening arrhythmias in patients in non-ischemic DCM undergoing ICD implantation for primary prevention, seemingly outperforming the clinical MADIT-ICD benefit score.