Brugada syndrome in Japan and Europe: a genome-wide association study reveals shared genetic architecture and new risk loci.

BACKGROUND AND AIMS: Brugada syndrome (BrS) is an inherited arrhythmia with a higher disease prevalence and more lethal arrhythmic events in Asians than in Europeans. Genome-wide association studies (GWAS) have revealed its polygenic architecture mainly in European populations. The aim of this study was to identify novel BrS-associated loci and to compare allelic effects across ancestries. METHODS: A GWAS was conducted in Japanese participants, involving 940 cases and 1634 controls, followed by a cross-ancestry meta-analysis of Japanese and European GWAS (total of 3760 cases and 11 635 controls). The novel loci were characterized by fine-mapping, gene expression, and splicing quantitative trait associations in the human heart. RESULTS: The Japanese-specific GWAS identified one novel locus near ZSCAN20 (P = 1.0 × 10-8), and the cross-ancestry meta-analysis identified 17 association signals, including six novel loci. The effect directions of the 17 lead variants were consistent (94.1%; P for sign test = 2.7 × 10-4), and their allelic effects were highly correlated across ancestries (Pearson's R = .91; P = 2.9 × 10-7). The genetic risk score derived from the BrS GWAS of European ancestry was significantly associated with the risk of BrS in the Japanese population [odds ratio 2.12 (95% confidence interval 1.94-2.31); P = 1.2 × 10-61], suggesting a shared genetic architecture across ancestries. Functional characterization revealed that a lead variant in CAMK2D promotes alternative splicing, resulting in an isoform switch of calmodulin kinase II-δ, favouring a pro-inflammatory/pro-death pathway. CONCLUSIONS: This study demonstrates novel susceptibility loci implicating potentially novel pathogenesis underlying BrS. Despite differences in clinical expressivity and epidemiology, the polygenic architecture of BrS was substantially shared across ancestries.

Long-term cause-specific mortality in adolescent and young adult Hodgkin lymphoma patients treated with contemporary regimens-A nationwide Danish cohort study.

The documented treatment-induced excess mortality in Hodgkin lymphoma (HL) has spurred important treatment changes over recent decades. This study aimed to examine mortality among young HL patients treated with contemporary strategies, including historical data comparison. This nationwide study included 1348 HL patients, diagnosed in 1995-2015 and aged 15-40 at diagnosis. Among the patients, 66.5% had Ann Arbor stage I-II and 33.5% had stage III-IV disease. With a median follow-up of 14.76 years, 139 deaths occurred, yielding a 5-year overall survival of 94.6%. Older age, advanced disease, earlier treatment periods and extensive regimens were associated with higher overall mortality risk. The cumulative risk of HL-related death showed an initial sharp rise, with a plateau at 5.3% 10-year post-diagnosis. Deaths due to cardiovascular or pulmonary diseases and second cancers initially had minimal risk, gradually reaching 1.2% and 2.0% at the 20-year mark respectively. HL cases had a 7.5-fold higher mortality hazard than the background population. This study suggests that contemporary HL treatment still poses excess mortality risk, but recent changes have notably reduced overall and cause-specific mortality compared to earlier eras. Balancing treatment efficacy and toxicity remains crucial, but our findings highlight improved outcomes with modern treatment approaches.

Long-term prognostic outcomes and implication of oral anticoagulants in patients with new-onset atrial fibrillation following st-segment elevation myocardial infarction.

BACKGROUND: New-onset atrial fibrillation (NEW-AF) following ST-segment elevation myocardial infarction (STEMI) is a common complication, but the true prognostic impact of NEW-AF is unknown. Additionally, the optimal treatment of NEW-AF among patients with STEMI is warranted. METHODS: A large cohort of consecutive patients with STEMI treated with percutaneous coronary intervention were identified using the Eastern Danish Heart Registry from 1999-2016. Medication and end points were retrieved from Danish nationwide registries. NEW-AF was defined as a diagnosis of AF within 30 days following STEMI. Patients without a history of AF and alive after 30 days after discharge were included. Incidence rates were calculated and multivariate analyses performed to determine the association between NEW-AF and long-term mortality, incidence of ischemic stroke, re-MI, and bleeding leading to hospitalization, and the comparative effectiveness of OAC therapy on these outcomes. RESULTS: Of 7944 patients with STEMI, 296 (3.7%) developed NEW-AF. NEW-AF was associated with increased long-term mortality (adjusted HR 1.48, 95% CI 1.20-1.82, P<.001) and risk of bleeding leading to hospitalization (adjusted HR 1.36, 95% CI 1.00-1.85, P=.050), and non-significant increased risk of ischemic stroke (adjusted HR 1.45, 95% CI 0.96-2.19, P=.08) and re-MI (adjusted HR 1.14, 95% CI 0.86-1.52, P=.35) with a median follow-up of 5.8 years. In NEW-AF patients, 38% received OAC therapy, which was associated with reduced long-term mortality (adjusted HR 0.69, 95% CI 0.47-1.00, P=.049). CONCLUSIONS: NEW-AF following STEMI is associated with increased long-term mortality. Treatment with OAC therapy in NEW-AF patients is associated with reduced long-term mortality.

Enhancing rare variant interpretation in inherited arrhythmias through quantitative analysis of consortium disease cohorts and population controls.

PURPOSE: Stringent variant interpretation guidelines can lead to high rates of variants of uncertain significance (VUS) for genetically heterogeneous disease like long QT syndrome (LQTS) and Brugada syndrome (BrS). Quantitative and disease-specific customization of American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines can address this false negative rate. METHODS: We compared rare variant frequencies from 1847 LQTS (KCNQ1/KCNH2/SCN5A) and 3335 BrS (SCN5A) cases from the International LQTS/BrS Genetics Consortia to population-specific gnomAD data and developed disease-specific criteria for ACMG/AMP evidence classes-rarity (PM2/BS1 rules) and case enrichment of individual (PS4) and domain-specific (PM1) variants. RESULTS: Rare SCN5A variant prevalence differed between European (20.8%) and Japanese (8.9%) BrS patients (p = 5.7 × 10-18) and diagnosis with spontaneous (28.7%) versus induced (15.8%) Brugada type 1 electrocardiogram (ECG) (p = 1.3 × 10-13). Ion channel transmembrane regions and specific N-terminus (KCNH2) and C-terminus (KCNQ1/KCNH2) domains were characterized by high enrichment of case variants and >95% probability of pathogenicity. Applying the customized rules, 17.4% of European BrS and 74.8% of European LQTS cases had (likely) pathogenic variants, compared with estimated diagnostic yields (case excess over gnomAD) of 19.2%/82.1%, reducing VUS prevalence to close to background rare variant frequency. CONCLUSION: Large case-control data sets enable quantitative implementation of ACMG/AMP guidelines and increased sensitivity for inherited arrhythmia genetic testing.

Clinical characteristics and risk factors of arrhythmia during follow-up of patients with idiopathic ventricular fibrillation.

AIMS: The current knowledge of idiopathic ventricular fibrillation (IVF) is limited. We aimed to investigate the nature of IVF, including clinical assessment and later diagnosis, and risk factors of implantable cardioverter defibrillator (ICD) therapy in the follow-up period. METHODS: Between 2007 and 2019 we systematically identified all patients from Rigshospitalet, Denmark, with a resuscitated sudden cardiac arrest (SCA) with no identifiable cause. All patients were followed routinely in the ICD outpatient clinic and the majority also in an inherited heart disease outpatient clinic. Outcomes were analysed with Cox regressions models and cumulative incidence curves. RESULTS: We identified 84 patients with an initial diagnosis of IVF; of these, three (3.6%) patients were later diagnosed with a cardiac disease. The remaining IVF patients (n = 81, median age 45 years; men 71.6%) were followed a median follow-up of 5.2 years (interquartile range, 2.0-7.6). A total of 24 (29.6%) patients had appropriate ICD therapy and 12 (14.8%) patients had inappropriate ICD therapy. No predominant type of ventricular arrhythmia at first appropriate ICD therapy was observed. Early repolarization at baseline was not associated with an increased risk of appropriate ICD therapy (P = .842). Repeated cardiac arrest at index SCA increased the risk of appropriate ICD therapy (hazard ratio, 2.63 [95% CI, 1.08-6.40; P = .033]). CONCLUSION: Most patients remained idiopathic throughout the follow-up period and the overall long-term prognosis of IVF was good. Repeated cardiac arrest at index SCA was a risk factor of appropriate ICD therapy and early repolarization was not associated with an increased risk of appropriate ICD therapy.

A comprehensive evaluation of the genetic architecture of sudden cardiac arrest.

Aims: Sudden cardiac arrest (SCA) accounts for 10% of adult mortality in Western populations. We aim to identify potential loci associated with SCA and to identify risk factors causally associated with SCA. Methods and results: We carried out a large genome-wide association study (GWAS) for SCA (n = 3939 cases, 25 989 non-cases) to examine common variation genome-wide and in candidate arrhythmia genes. We also exploited Mendelian randomization (MR) methods using cross-trait multi-variant genetic risk score associations (GRSA) to assess causal relationships of 18 risk factors with SCA. No variants were associated with SCA at genome-wide significance, nor were common variants in candidate arrhythmia genes associated with SCA at nominal significance. Using cross-trait GRSA, we established genetic correlation between SCA and (i) coronary artery disease (CAD) and traditional CAD risk factors (blood pressure, lipids, and diabetes), (ii) height and BMI, and (iii) electrical instability traits (QT and atrial fibrillation), suggesting aetiologic roles for these traits in SCA risk. Conclusions: Our findings show that a comprehensive approach to the genetic architecture of SCA can shed light on the determinants of a complex life-threatening condition with multiple influencing factors in the general population. The results of this genetic analysis, both positive and negative findings, have implications for evaluating the genetic architecture of patients with a family history of SCA, and for efforts to prevent SCA in high-risk populations and the general community.

Febrile seizures prior to sudden cardiac death: a Danish nationwide study.

Aims: Febrile seizure (FS) is a common disorder affecting 2-5% of children up to 5 years of age. The aim of this study was to determine whether FS in early childhood are over-represented in young adults dying from sudden cardiac death (SCD). Methods and results: We included all deaths (n = 4595) nationwide and through review of all death certificates, we identified 245 SCD in Danes aged 1-30 years in 2000-09. Through the usage of nationwide registries, we identified all persons admitted with first FS among SCD cases (14/245; 5.7%) and in the corresponding living Danish population (71 027/2 369 785; 3.0%) and also in victims of transport accidents (26/917; 2.8%). The frequency of FS among SCD cases was significantly increased by an odds ratio of 1.96 [95% confidence interval (CI) 1.14-3.36; P = 0.021] compared with the living Danish population and with an odds ratio of 2.08 (95% CI 1.07-4.04; P = 0.046) compared with transport accident victims. SCD cases did not differ statistically in birth year (P = 0.272), age at SCD (P = 0.667) or prior medical conditions, except for epilepsy (P < 0.001), when comparing SCD with and without prior FS. The most common cause of death in autopsied SCD cases with FS was sudden arrhythmic death syndrome (5/8; 62.5%). Conclusion: In conclusion, this study demonstrates a significantly two-fold increase in the frequency of FS prior to death in young SCD cases compared with the two control groups, suggesting that FS could potentially contribute in a risk stratification model for SCD and warrant further studies.

Post-mortem toxicology in young sudden cardiac death victims: a nationwide cohort study.

Aims: Several drugs increase the risk of ventricular fibrillation and sudden cardiac death (SCD). We aimed to investigate in detail the toxicological findings of all young SCD throughout Denmark. Methods and results: Deaths in persons aged 1-49 years were included over a 10-year period. Death certificates and autopsy reports were retrieved and read to identify cases of sudden death and establish cause of death. All medico-legal autopsied SCD were included and toxicological reports collected. Positive toxicology was defined as the presence of any substance (licit and/or illicit). All toxicological findings had previously been evaluated not to have caused the death (i.e. lethal concentrations were excluded). We identified 620 medico-legal autopsied cases of SCD, of which 77% (n = 477) were toxicologically investigated post-mortem, and 57% (n = 270) had a positive toxicology profile. Sudden cardiac death with positive toxicology had higher rates of sudden arrhythmic death syndrome (SADS), compared with SCD with negative toxicology (56% vs. 42%, P < 0.01). In total, 752 agents were detected, and polypharmacy (defined as the presence of more than one drug) was present in 61% (n = 164), all substances combined. Psychotropic drugs were the most frequent (62%, n = 467), and 82% (n = 385) were in pharmacological or subpharmacological levels. Conclusion: We found that more than half of all toxicologically investigated SCD victims have positive post-mortem toxicological findings, and polypharmacy is displayed in a considerable proportion. SCD with positive toxicology had higher rate of SADS, suggesting that the compounds may play a proarrhythmic role in these cases.

Association of common genetic variants related to atrial fibrillation and the risk of ventricular fibrillation in the setting of first ST-elevation myocardial infarction.

BACKGROUND: Cohort studies have revealed an increased risk for ventricular fibrillation (VF) and sudden cardiac death (SCD) in patients with atrial fibrillation (AF). In this study, we hypothesized that single nucleotide polymorphisms (SNP) previously associated with AF may be associated with the risk of VF caused by first ST-segment elevation myocardial infarction (STEMI). METHODS: We investigated association of 24 AF-associated SNPs with VF in the prospectively assembled case-control study among first STEMI-patients of Danish ancestry. RESULTS: We included 257 cases (STEMI with VF) and 537 controls (STEMI without VF). The median age at index infarction was 60 years for the cases and 61 years for the controls (p = 0.100). Compared to the control group, the case group was more likely to be male (86% vs. 75%, p = 0.001), have a history of AF (7% vs. 2%, p = 0.006) or hypercholesterolemia (39% vs. 31%, p = 0.023), and a family history of sudden death (40% vs. 25%, p < 0.001). All 24 selected SNPs have previously been associated with AF. None of the 24 SNPs were associated with the risk of VF after adjustment for age and sex under additive genetic model of inheritance in the logistic regression model. CONCLUSION: In this study, we found that the 24 AF-associated SNPs may not be involved in increasing the risk of VF. Larger VF cohorts and use of new next generation sequencing and epigenetic may in future identify additional AF and VF risk loci and improve our understanding of genetic pathways behind the two arrhythmias.

Gender differences in sudden cardiac death in the young-a nationwide study.

BACKGROUND: Hitherto, sudden cardiac death (SCD) in the young has been described with no distinction between genders. SCD occurs more often in men (SCDm) than women (SCDw), but this disparity is not understood and has not been investigated systematically in a nationwide setting. Our objective was to report gender differences in SCD in the young in a nationwide (Denmark) setting. METHODS: All deaths in persons aged 1-35 years nationwide in Denmark between 2000 and 2009 were included. Death certificates and autopsy reports were obtained. The extensive health care registries in Denmark were used to investigate any known disease prior to death. SCDw were compared to SCDm. RESULTS: During the 10-year study period there were a total of 8756 deaths in 23.7 million person-years. In total, 635 deaths were SCD. SCDw constituted 205 deaths (32%). Women had a higher proportion of witnessed deaths (51 vs. 41%, p = 0.02) and died less often in a public place (16 vs. 26%, p = 0.01). Age at death, ratios of autopsies and sudden unexplained deaths, and comorbidities, did not differ. Causes of SCD were largely comparable between genders. The incidence rate of SCDw was half of that of SCDm (1.8 vs. 3.6 per 100,000 person-years, incidence rate ratio 2.0 (95% CI 1.7-2.4), p < 0.01). CONCLUSIONS: Incidence rate ratio of SCDm vs SCDw is 2. Young SCDw and SCDm are equally investigated, have comparable comorbidity, and causes of SCD. SCD due to potentially inherited cardiac diseases is less often in young women and could reflect a protection of female gender.

Cardiac symptoms before sudden cardiac death caused by hypertrophic cardiomyopathy: a nationwide study among the young in Denmark.

AIMS: Hypertrophic cardiomyopathy (HCM) is a frequent cause of sudden cardiac death (SCD) among the young (SCDY). The aim of this study was to characterize symptoms before SCDY due to HCM. METHODS AND RESULTS: Through review of all death certificates, we identified all SCDs in Danes aged 1-35 years in 2000-2009. Nationwide we included all deaths (n = 8756) and identified 431 autopsied SCDYs. All available records from hospitals and general practitioners were retrieved. To compare symptoms, we included a control groups consisting of traffic accident victims (n = 74). In the 10-year study period, 431 autopsied SCDY cases were reviewed and 38 cases (9%) were included, of which 22 (58%) had morphologic findings diagnostic of HCM and 16 (42%) had findings suggestive, but not diagnostic, of HCM ('possible HCM'). Cardiac symptoms >1 h prior to death were reported in 21 (55%) of cases, and 16 (42%) sought medical attention. One (1%) control had cardiac symptoms before death. Consequently, a significantly higher proportion of cases had cardiac symptoms before death and cases more often sought medical attention than controls (P < 0.001). CONCLUSION: In conclusion, this nationwide study demonstrates a high frequency of cardiac symptoms prior to death in SCDY cases who died of HCM, as 55% had cardiac symptoms and nearly half of the cases sought medical attention.

Symptoms Before Sudden Arrhythmic Death Syndrome: A Nationwide Study Among the Young in Denmark.

INTRODUCTION: No studies in an unselected and nationwide setting have characterized the symptoms and medical history of patients with sudden arrhythmic death syndrome (SADS). The aim of this study was to identify and describe the symptoms and medical history of patients before the presentation of SADS. METHODS AND RESULTS: We have previously identified all of the autopsied sudden cardiac deaths (SCD; n = 314) in Danes aged 1-35 years between 2000 and 2006. After comprehensive pathological and toxicological investigation did not reveal a cause of SCD, 136 of the patients were identified as SADS. The National Patient Registry was utilized to obtain information on all in- and outpatient activity in Danish hospitals. All medical records from hospitals and general practitioners, including death certificates and autopsy reports were reviewed. Before death, 48 (35%) SADS patients had cardiac symptoms; among these, 30 (22%) had contacted the healthcare system. Antecedent symptoms (symptoms >24 hours before death) were present in 34 (25%) patients. Prodromal symptoms (symptoms ≤24 hours before death) were present in 23 (17%) patients. Cardiac symptoms included chest pain (n = 16, 12%), dyspnea (n = 18, 13%), palpitations (n = 2, 1%), presyncope/syncope (n = 23, 17%), and aborted SCD (n = 2, 1%). In addition, seizures (n = 25, 18%) were prevalent. In 61 (45%) SADS cases, no previous medical history were recorded. CONCLUSION: In this unselected, nationwide study of 136 young SADS patients, 35% had experienced cardiac symptoms before death, most commonly presyncope/syncope, but only one out of five had contacted a healthcare provider with cardiac symptoms.

Sudden death in young persons with uncontrolled asthma--a nationwide cohort study in Denmark.

BACKGROUND: Asthma is a common chronic disease among young adults, and several studies have reported increased mortality rates in patients with asthma. However, no study has described sudden unexpected death in a nationwide setting in patients with uncontrolled asthma. We defined uncontrolled asthma as a previous hospital admittance because of asthma (of any severity) or when asthma was considered to have influenced the death according to the death certificate. The purpose of this study is to increase the medical focus on young persons with uncontrolled asthma and thereby hopefully aid in preventing sudden unexpected deaths. We therefore aimed to describe clinical characteristics, symptoms, causes of death, and contact with the healthcare system prior to sudden unexpected death in young persons with uncontrolled asthma. METHODS: Through the review of death certificates, we found 625 sudden unexpected death cases in individuals aged 1-35 years in Denmark from 2000 to 2006. Of those, 49 persons with uncontrolled asthma were identified. Previous contacts with the healthcare system were identified, and available records from general practitioners were retrieved. RESULTS: We identified 49 individuals who suffered from uncontrolled asthma. This corresponds to an incidence rate of 0.32 per 100,000 person-years. The cause of death in 31 cases (63%) was sudden cardiac death, and in 13 cases (27%), it was a fatal asthma attack. Symptoms (chest pain, dyspnea, seizures, general malaise, syncope, and palpitations) prior to death were reported in 41 (84%) of the cases. In 34 (69%) of the cases, antecedent symptoms (symptoms >24 hours before death) were present, and 28 (57%) patients had prodromal symptoms (symptoms <24 hours before death). The most common antecedent symptoms were dyspnea and chest pain, whereas the most common prodromal symptoms were dyspnea, general malaise, and/or fatigue. Twenty-eight patients (57%) sought medical advice from a general practitioner and/or emergency department due to these symptoms. CONCLUSION: The cause of death was predominantly sudden cardiac death followed by fatal asthma attack. We found that 41 (84%) of patients suffered from symptoms prior to death and that 28 (57%) sought medical advice from the emergency department and/or general practitioners.

Discovery of plasma proteins associated with ventricular fibrillation during first ST-elevation myocardial infarction via proteomics.

AIMS: The underlying biological mechanisms of ventricular fibrillation (VF) during acute myocardial infarction are largely unknown. To our knowledge, this is the first proteomic study for this trait, with the aim to identify and characterize proteins that are associated with VF during first ST-elevation myocardial infarction (STEMI). METHODS AND RESULTS: We included 230 participants from a Danish ongoing case-control study on patients with first STEMI with VF (case, n = 110) and without VF (control, n = 120) before guided catheter insertion for primary percutaneous coronary intervention. The plasma proteome was investigated using mass spectrometry-based proteomics on plasma samples collected within 24 h of symptom onset, and one patient was excluded in quality control. In 229 STEMI patients {72% men, median age 62 years [interquartile range (IQR): 54-70]}, a median of 257 proteins (IQR: 244-281) were quantified per patient. A total of 26 proteins were associated with VF; these proteins were involved in several biological processes including blood coagulation, haemostasis, and immunity. After correcting for multiple testing, two up-regulated proteins remained significantly associated with VF, actin beta-like 2 [ACTBL2, fold change (FC) 2.25, P < 0.001, q = 0.023], and coagulation factor XIII-A (F13A1, FC 1.48, P < 0.001, q = 0.023). None of the proteins were correlated with anterior infarct location. CONCLUSION: Ventricular fibrillation due to first STEMI was significantly associated with two up-regulated proteins (ACTBL2 and F13A1), suggesting that they may represent novel underlying molecular VF mechanisms. Further research is needed to determine whether these proteins are predictive biomarkers or acute phase response proteins to VF during acute ischaemia.

Toxicological profile using mass spectrometry in sudden cardiac arrest survivors admitted to a tertiary centre.

BACKGROUND: There has been no previous thorough toxicological examination of a cohort of patients with resuscitated sudden cardiac arrest. We aimed to determine the qualitative and quantitative drug composition in a resuscitated sudden cardiac arrest population, using forensic toxicology, with focus on prescribed, non-prescribed, and commonly abused drugs. METHODS: Individuals aged 18-90 years with resuscitated sudden cardiac arrest of presumed cardiac causes were prospectively included from a single tertiary center. Data from the sudden cardiac arrest hospitalization was collected from medical reports. Drugs used during resuscitation or before the blood sampling were identified and excluded in each patient. Mass spectrometry-based toxicology was performed to determine the absence or presence of most drugs and to quantify the findings. RESULTS: Among 186 consecutively enrolled resuscitated sudden cardiac arrest patients (median age 62 years, 83% male), 90% had a shockable rhythm, and were primarily caused by ischemic heart disease (66%). In total, 90 different drugs (excluding metabolites) were identified, and 82% of patients had at least one drug detected (median of 2 detected drugs (IQR:1-4)) (polypharmacy). Commonly abused drugs were present in 16%, and QT-prolonging drugs were present in 12%. Polypharmacy (≥5drugs) were found in 19% of patients. Importantly, none had potentially lethal concentrations of any drugs. CONCLUSION: In resuscitated sudden cardiac arrest patients with cardiac arrest of presumed cardiac cause, routine toxicological screening provides limited extra information. However, the role of polypharmacy in sudden cardiac arrest requires further investigation. No occult overdose-related cardiac arrests were identified.

Familial clustering of unexplained heart failure - A Danish nationwide cohort study.

AIMS: To determine whether a family history of unexplained heart failure (HF) in first-degree relatives (children or sibling) increases the rate of unexplained HF. METHODS AND RESULTS: Using Danish nationwide registry data (1978-2017), we identified patients (probands) diagnosed with first unexplained HF (HF without any known comorbidities) in Denmark, and their first-degree relatives. All first-degree relatives were followed from the HF date of the proband and until an event of unexplained HF, exclusion diagnosis, death, emigration, or study end, whichever occurred first. Using the general population as a reference, we calculated adjusted standardized incidence ratios (SIR) of unexplained HF in the three groups of relatives using Poisson regression models. We identified 55,110 first-degree relatives to individuals previously diagnosed with unexplained HF. Having a family history was associated with a significantly increased unexplained HF rate of 2.59 (95%CI 2.29-2.93). The estimate was higher among siblings (SIR 6.67 [95%CI 4.69-9.48]). Noteworthy, the rate of HF increased for all first-degree relatives when the proband was diagnosed with HF in a young age (≤50 years, SIR of 7.23 [95%CI 5.40-9.68]) and having >1 proband (SIR of 5.28 [95%CI 2.75-10.14]). The highest estimate of HF was observed if the proband was ≤40 years at diagnosis (13.17 [95%CI 8.90-19.49]. CONCLUSION: A family history of unexplained HF was associated with a two-fold increased rate of unexplained HF among first-degree relatives. The relative rate was increased when the proband was diagnosed at a young age. These data suggest that screening families of unexplained HF with onset below 50 years is indicated.

Bleeding risk and P2Y12 inhibitors in all-comer patients with ST-segment elevation myocardial infarction treated with percutaneous coronary intervention: a single-centre cohort study.

AIMS: To characterize and follow patients with ST-segment elevation myocardial infarction (STEMI) at high bleeding risk (HBR) according to the predicting bleeding complications in patients undergoing stent implantation and subsequent dual antiplatelet therapy (PRECISE-DAPT) score, and to examine the use of P2Y12 inhibitors and the subsequent risk of major adverse cardiovascular events (MACE) and bleeding. METHODS AND RESULTS: This single-centre cohort study included 6179 consecutive STEMI patients who underwent percutaneous coronary intervention (PCI) at Copenhagen University Hospital, Rigshospitalet, between 2009 and 2016. Individual linkage to nationwide registries was conducted to obtain information on diagnoses, claimed drugs, and vital status. Of the 5532 (89.5%) patients with available PRECISE-DAPT scores, 33.0% were at HBR and more often elderly and female with more comorbidities than non-HBR patients. One-year cumulative incidence rates per 100 person-years were 8.7 and 2.1 for major bleeding and 36.8 and 8.3 for MACE in HBR and non-HBR patients, respectively. Among the 4749 (85.8%) patients who survived and collected a P2Y12 inhibitor ≤7 days from discharge, 68.2% of HBR patients were treated with ticagrelor or prasugrel and 31.8% with clopidogrel, while 18.2% non-HBR patients were treated with clopidogrel. Adherence was high for all (>75% days coverage). The risk of MACE was lower in ticagrelor- and prasugrel-treated patients than in clopidogrel-treated patients without differences in major bleeding. CONCLUSION: One-third of PCI-treated all-comer patients with STEMI were at HBR according to the PRECISE-DAPT score and were more often treated with potent P2Y12 inhibitors instead of clopidogrel. Thus, ischaemic risk may be weighted over bleeding risk in STEMI patients at HBR.

Risk of Sudden Infant Death Syndrome Among Siblings of Children Who Died of Sudden Infant Death Syndrome in Denmark.

Importance: Sudden infant death syndrome (SIDS) remains a leading cause of death during the first year of life. The etiology of SIDS is complex and remains largely unknown. Objective: To evaluate whether siblings of children who died of SIDS have a higher risk of SIDS compared with the general pediatric population. Design, Setting, and Participants: This register-based cohort study used Danish nationwide registers. Participants were all infants (<1 year) in Denmark between January 1, 1978, and December 31, 2016, including siblings of children who died of SIDS. Siblings were followed up from the index cases' date of SIDS, date of birth, or immigration, whichever came first, and until age 1 year, emigration, developing SIDS, death, or study end. The median (IQR) follow-up was 1 (1-1) year. Data analysis was conducted from January 2017 to October 2022. Main Outcomes and Measures: Standardized incidence ratios (SIRs) of SIDS were calculated with Poisson regression models relative to the general population. Results: In a population of 2 666 834 consecutive births (1 395 199 [52%] male), 1540 infants died of SIDS (median [IQR] age at SIDS, 3 [2-4] months) during a 39-year study period. A total of 2384 younger siblings (cases) to index cases (first sibling with SIDS) were identified. A higher rate of SIDS was observed among siblings compared with the general population, with SIRs of 4.27 (95% CI, 2.13-8.53) after adjustment for sex, age, and calendar year and of 3.50 (95% CI, 1.75-7.01) after further adjustment for mother's age (<29 years vs ≥29 years) and education (high school vs after high school). Conclusions and Relevance: In this nationwide study, having a sibling who died of SIDS was associated with a 4-fold higher risk of SIDS compared with the general population. Shared genetic and/or environmental factors may contribute to the observed clustering of SIDS. The family history of SIDS should be considered when assessing SIDS risk in clinical settings. A multidisciplinary genetic evaluation of families with SIDS could provide additional evidence.

Comparison of Effect of Ischemic Postconditioning on Cardiovascular Mortality in Patients With ST-Segment Elevation Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention With Versus Without Thrombectomy.

In patients with ST-segment elevation myocardial infarction (STEMI), ischemic postconditioning (iPOST) have shown ambiguous results in minimizing reperfusion injury. Previous findings show beneficial effects of iPOST in patients with STEMI treated without thrombectomy. However, it remains unknown whether the cardioprotective effect of iPOST in these patients persist on long term. In the current study, all patients were identified through the DANAMI-3-iPOST database. Patients were randomized to conventional primary percutaneous coronary intervention (PCI) or iPOST in addition to PCI. Cumulative incidence rates were calculated, and multivariable analyses stratified according to thrombectomy use were performed. The primary end point was a combination of cardiovascular mortality and hospitalization for heart failure. From 2011 to 2014, 1,234 patients with STEMI were included with a median follow-up of 4.8 years. In patients treated without thrombectomy (n = 520), the primary end point occurred in 15% (48/326) in the iPOST group and in 22% (42/194) in the conventional group (unadjusted hazard ratio [HR] 0.62, 95% confidence interval [CI] 0.41 to 0.94, p = 0.023). In adjusted Cox analysis, iPOST remained associated with reduced long-term risk of cardiovascular mortality (HR 0.53, 95% CI 0.29 to 0.97, p = 0.039). In patients treated with thrombectomy (n = 714), there was no significant difference between iPOST (17%, 49/291) and conventional treatment (17%, 72/423) on the primary end point (unadjusted HR 1.01, 95% CI 0.70 to 1.45, p = 0.95). During a follow-up of nearly 5 years, iPOST reduced long-term occurrence of cardiovascular mortality and hospitalization for heart failure in patients with STEMI treated with PCI but without thrombectomy.

Genome-wide association analyses identify new Brugada syndrome risk loci and highlight a new mechanism of sodium channel regulation in disease susceptibility.

Brugada syndrome (BrS) is a cardiac arrhythmia disorder associated with sudden death in young adults. With the exception of SCN5A, encoding the cardiac sodium channel NaV1.5, susceptibility genes remain largely unknown. Here we performed a genome-wide association meta-analysis comprising 2,820 unrelated cases with BrS and 10,001 controls, and identified 21 association signals at 12 loci (10 new). Single nucleotide polymorphism (SNP)-heritability estimates indicate a strong polygenic influence. Polygenic risk score analyses based on the 21 susceptibility variants demonstrate varying cumulative contribution of common risk alleles among different patient subgroups, as well as genetic associations with cardiac electrical traits and disorders in the general population. The predominance of cardiac transcription factor loci indicates that transcriptional regulation is a key feature of BrS pathogenesis. Furthermore, functional studies conducted on MAPRE2, encoding the microtubule plus-end binding protein EB2, point to microtubule-related trafficking effects on NaV1.5 expression as a new underlying molecular mechanism. Taken together, these findings broaden our understanding of the genetic architecture of BrS and provide new insights into its molecular underpinnings.