Validation of the ARIC prediction model for sudden cardiac death in the European population: The ESCAPE-NET project.

BACKGROUND: Sudden cardiac death is responsible for 10% to 20% of all deaths in Europe. The current study investigates how well the risk of sudden cardiac death can be predicted. To this end, we validated a previously developed prediction model for sudden cardiac death from the Atherosclerosis Risk in Communities study (USA). METHODS: Data from participants of the Copenhagen City Heart Study (CCHS) (n=9988) was used to externally validate the previously developed prediction model for sudden cardiac death. The model's performance was assessed through discrimination (C-statistic) and calibration by the Hosmer-Lemeshow goodness-of-fit (HL) statistics suited for censored data and visual inspection of calibration plots. Additional validation was performed using data from the Hoorn Study (N=2045), employing the same methods. RESULTS: During ten years of follow-up of CCHS participants (mean age: 58.7 years, 56.2% women), 425 experienced SCD (4.2%). The prediction model showed good discrimination for sudden cardiac death risk (C-statistic: 0.81, 95% CI: 0.79-0.83). Calibration was robust (HL statistic: P=0.8). Visual inspection of the calibration plot showed that the calibration could be improved. Sensitivity was 89.8%, and specificity was 60.6%. The positive and negative predictive values were 10.1% and 99.2%. Model performance was similar in the Hoorn Study (C-statistic: 0.81, 95% CI: 0.77-0.85 and the HL statistic: 1.00). CONCLUSION: Our study showed that the previously developed prediction model in North American adults performs equally well in identifying those at risk for sudden cardiac death in a general North-West European population. However, the positive predictive value is low.

Scar border zone mass and presence of border zone channels assessed with cardiac magnetic resonance imaging are associated with ventricular arrhythmia in patients with ST-segment elevation myocardial infarction.

AIMS: Late gadolinium enhancement cardiac magnetic resonance (CMR) permits characterization of left ventricular ischaemic scars. We aimed to evaluate if scar core mass, border zone (BZ) mass, and BZ channels are risk markers for subsequent ventricular arrhythmia (VA) in ST-segment elevation myocardial infarction (STEMI). METHODS AND RESULTS: A sub-study of the DANish Acute Myocardial Infarction-3 multi-centre trial and Danegaptide phase II proof-of-concept clinical trial in which a total of 843 STEMI patients had a 3-month follow-up CMR. Of these, 21 patients subsequently experienced VA during 100 months of follow-up and were randomly matched 1:5 with 105 controls. A VA event was defined as: ventricular tachycardia, ventricular fibrillation, or sudden cardiac death. Ischaemic scar characteristics were automatically detected by specialized software. We included 126 patients with a median left ventricular ejection fraction of 51.0 ± 11.6% in cases with VA vs. 55.5 ± 8.5% in controls (P = 0.10). Cases had a larger mean BZ mass and more often BZ channels compared to controls [BZ mass: 17.2 ± 10.3 g vs. 10.3 ± 6.0 g; P = 0.0002; BZ channels: 17 (80%) vs. 44 (42%); P = 0.001]. A combination of ≥17.2 g BZ mass and the presence of BZ channels was five times more prevalent in cases vs. controls (P ≤ 0.00001) with an odds ratio of 9.40 (95% confidence interval 3.26-27.13; P ≤ 0.0001) for VA. This identified cases with 52% sensitivity and 90% specificity. CONCLUSION(S): Scar characterization with CMR indicates that a combination of ≥17.2 g BZ mass and the presence of BZ channels had the strongest association with subsequent VA in STEMI patients. CLINICALTRIALS.GOV: Unique identifier: NCT01435408 (DANAMI 3-iPOST and DANAMI 3-DEFER), NCT01960933 (DANAMI 3-PRIMULTI), and NCT01977755 (Danegaptide).

Long-term risk of new-onset arrhythmia in ST-segment elevation myocardial infarction according to revascularization status.

AIMS: Emerging data show that complete revascularization (CR) reduces cardiovascular death and recurrent myocardial infarction in ST-segment elevation myocardial infarction (STEMI). However, the influence of revascularization status on development of arrhythmia in the long-term post-STEMI phase is poorly described. We hypothesized that incomplete revascularization (ICR) compared with CR in STEMI is associated with an increased long-term risk of new-onset arrhythmia. METHODS AND RESULTS: Patients with STEMI treated with primary percutaneous coronary intervention (PPCI) at Copenhagen University Hospital, Rigshospitalet, Denmark, with CR or ICR were identified via the Eastern Danish Heart registry from 2009 to 2016. Using unique Danish administrative registries, the outcomes were assessed. The primary outcome was new-onset arrhythmia defined as a composite of atrial fibrillation/flutter (AF), sinoatrial block, advanced second- or third-degree atrioventricular block, ventricular tachycardia/fibrillation (VT), or cardiac arrest (CA), with presentation >7 days post-PPCI. Secondary outcomes were the components of the primary outcome and all-cause mortality. A total of 5103 patients (median age: 62.0 years; 76% men) were included, of whom 4009 (79%) and 1094 (21%) patients underwent CR and ICR, respectively. Compared with CR, ICR was associated with a higher risk of new-onset arrhythmia [hazard ratio (HR), 1.33; 95% confidence interval (CI), 1.07-1.66; P = 0.01], AF (HR, 1.29; 95% CI, 1.00-1.66; P = 0.05), a combined outcome of VT and CA (HR, 1.77; 95% CI, 1.10-2.84; P = 0.02) and all-cause mortality (HR, 1.27; 95% CI, 1.05-1.53; P = 0.01). All HRs adjusted. CONCLUSION: Among patients with STEMI, ICR was associated with an increased long-term risk of new-onset arrhythmia and all-cause mortality compared with CR.

Cardiac Characteristics of the First Two Waves of COVID-19 in Denmark and the Prognostic Value of Echocardiography: The ECHOVID-19 Study.

INTRODUCTION: COVID-19 has spread globally in waves, and Danish treatment guidelines have been updated following the first wave. We sought to investigate whether the prognostic values of echocardiographic parameters changed with updates in treatment guidelines and the emergence of novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, 20E (EU1) and alpha (B.1.1.7), and further to compare cardiac parameters between patients from the first and second wave. METHODS: A total of 305 patients hospitalized with COVID-19 were prospectively included, 215 and 90 during the first and second wave, respectively. Treatment in the study was defined as treatment with remdesivir, dexamethasone, or both. Patients were assumed to be infected with the dominant SARS-CoV-2 variant at the time of their hospitalization. RESULTS: Mean age for the first versus second wave was 68.7 ± 13.6 versus 69.7 ± 15.8 years, and 55% versus 62% were males. Left ventricular (LV) systolic and diastolic function was worse in patients hospitalized during the second wave (LV ejection fraction [LVEF] for first vs. second wave = 58.5 ± 8.1% vs. 52.4 ± 10.6%, p < 0.001; and global longitudinal strain [GLS] = 16.4 ± 4.3% vs. 14.2 ± 4.3%, p < 0.001). In univariable Cox regressions, reduced LVEF (hazard ratio [HR] = 1.07 per 1% decrease, p = 0.002), GLS (HR = 1.21 per 1% decrease, p < 0.001), and tricuspid annular plane systolic excursion (HR = 1.18 per 1 mm decrease, p < 0.001) were associated with COVID-related mortality, but only GLS remained significant in fully adjusted analysis (HR = 1.14, p = 0.02). CONCLUSION: Reduced GLS was associated with COVID-related mortality independently of wave, treatment, and the SARS-CoV-2 variant. LV function was significantly impaired in patients hospitalized during the second wave.

Harmonization of the definition of sudden cardiac death in longitudinal cohorts of the European Sudden Cardiac Arrest network - towards Prevention, Education, and New Effective Treatments (ESCAPE-NET) consortium.

BACKGROUND: The burden of sudden cardiac death (SCD) in the general population is substantial and SCD frequently occurs among people with few or no known risk factors for cardiac disease. Reported incidences of SCD vary due to differences in definitions and methodology between cohorts. This study aimed to develop a method for adjudicating SCD cases in research settings and to describe uniform case definitions of SCD in an international consortium harmonizing multiple longitudinal study cohorts. METHODS: The harmonized SCD definitions include both case definitions using data from multiple sources (eg, autopsy reports, medical history, eyewitnesses) as well as a method using only information from registers (eg, cause of death registers, ICD-10 codes). Validation of the register-based method was done within the consortium using the multiple sources definition as gold standard and presenting sensitivity, specificity, accuracy and positive predictive value. RESULTS: Consensus definitions of "definite," "possible" and "probable" SCD for longitudinal study cohorts were reached. The definitions are based on a stratified approach to reflect the level of certainty of diagnosis and degree of information. The definitions can be applied to both multisource and register-based methods. Validation of the method using register-information in a cohort comprising 1335 cases yielded a sensitivity of 74%, specificity of 88%, accuracy of 86%, and positive predictive value of 54%. CONCLUSIONS: This study demonstrated that a harmonization of SCD classification across different methodological approaches is feasible. The developed classification can be used to study SCD in longitudinal cohorts and to merge cohorts with different levels of information.

Transethnic Genome-Wide Association Study Provides Insights in the Genetic Architecture and Heritability of Long QT Syndrome.

BACKGROUND: Long QT syndrome (LQTS) is a rare genetic disorder and a major preventable cause of sudden cardiac death in the young. A causal rare genetic variant with large effect size is identified in up to 80% of probands (genotype positive) and cascade family screening shows incomplete penetrance of genetic variants. Furthermore, a proportion of cases meeting diagnostic criteria for LQTS remain genetically elusive despite genetic testing of established genes (genotype negative). These observations raise the possibility that common genetic variants with small effect size contribute to the clinical picture of LQTS. This study aimed to characterize and quantify the contribution of common genetic variation to LQTS disease susceptibility. METHODS: We conducted genome-wide association studies followed by transethnic meta-analysis in 1656 unrelated patients with LQTS of European or Japanese ancestry and 9890 controls to identify susceptibility single nucleotide polymorphisms. We estimated the common variant heritability of LQTS and tested the genetic correlation between LQTS susceptibility and other cardiac traits. Furthermore, we tested the aggregate effect of the 68 single nucleotide polymorphisms previously associated with the QT-interval in the general population using a polygenic risk score. RESULTS: Genome-wide association analysis identified 3 loci associated with LQTS at genome-wide statistical significance (P<5×10-8) near NOS1AP, KCNQ1, and KLF12, and 1 missense variant in KCNE1(p.Asp85Asn) at the suggestive threshold (P<10-6). Heritability analyses showed that ≈15% of variance in overall LQTS susceptibility was attributable to common genetic variation (h2SNP 0.148; standard error 0.019). LQTS susceptibility showed a strong genome-wide genetic correlation with the QT-interval in the general population (rg=0.40; P=3.2×10-3). The polygenic risk score comprising common variants previously associated with the QT-interval in the general population was greater in LQTS cases compared with controls (P<10-13), and it is notable that, among patients with LQTS, this polygenic risk score was greater in patients who were genotype negative compared with those who were genotype positive (P<0.005). CONCLUSIONS: This work establishes an important role for common genetic variation in susceptibility to LQTS. We demonstrate overlap between genetic control of the QT-interval in the general population and genetic factors contributing to LQTS susceptibility. Using polygenic risk score analyses aggregating common genetic variants that modulate the QT-interval in the general population, we provide evidence for a polygenic architecture in genotype negative LQTS.

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.

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.

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.

New population-based exome data question the pathogenicity of some genetic variants previously associated with Marfan syndrome.

BACKGROUND: Marfan syndrome (MFS) is a rare autosomal dominantly inherited connective tissue disorder with an estimated prevalence of 1:5,000. More than 1000 variants have been previously reported to be associated with MFS. However, the disease-causing effect of these variants may be questionable as many of the original studies used low number of controls. To study whether there are possible false-positive variants associated with MFS, four in silico prediction tools (SIFT, Polyphen-2, Grantham score, and conservation across species) were used to predict the pathogenicity of these variant. RESULTS: Twenty-three out of 891 previously MFS-associated variants were identified in the ESP. These variants were distributed on 100 heterozygote carriers in 6494 screened individuals. This corresponds to a genotype prevalence of 1:65 for MFS. Using a more conservative approach (cutoff value of >2 carriers in the EPS), 10 variants affected a total of 82 individuals. This gives a genotype prevalence of 1:79 (82:6494) in the ESP. A significantly higher frequency of MFS-associated variants not present in the ESP were predicted to be pathogenic with the agreement of ≥3 prediction tools, compared to the variants present in the ESP (p = 3.5 × 10-15). CONCLUSIONS: This study showed a higher genotype prevalence of MFS than expected from the phenotype prevalence in the general population. The high genotype prevalence suggests that these variants are not the monogenic cause of MFS. Therefore, caution should be taken with regard to disease stratification based on these previously reported MFS-associated variants.

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.

Prior myocardial infarction in the young: predisposes to a high relative risk but low absolute risk of a sudden cardiac death.

AIMS: The study reports the relative and absolute risk of sudden cardiac death (SCD) in patients <36 years with prior myocardial infarction (MI). METHODS AND RESULTS: Through review of death certificates, we identified all SCDs in Danes aged 18-35 years between 1 January 2000 until 31st December 2006. We then used the unique Danish civil registration number, which enabled us to follow all Danes in national registries, in the same period. Through the National Patient Registry we identified those with a prior myocardial infarction [implantable cardioverter defibrillator (ICD)-8: 410, ICD-10: I21 and I22] and incidence rates for SCD were estimated for survivors of MI and for individuals who had not yet suffered an MI, respectively. We estimated the relative risk of SCD and all-cause mortality by using extended Cox regression models. The 1,862,431 Danes aged between 18 and 35 years were followed in 9,388,453 person-years between 2000 and 2006. There were 7434 deaths of which 387 (5.2%) were SCDs. Myocardial infarction was diagnosed in 1234 patients, of those 10 died of SCD. Prior MI increased the incidence rate of SCD from 4.1 to 305.0 per 100,000 person-years [95% confidence interval (CI): 164.1-567.0]. Myocardial infarction was correlated with SCD and all-cause mortality, with a hazard ratio (HR) of 55.5 (95% CI: 29.5-104.4), P< 0.0001 and HR 8.3 (95% CI: 6.0-11.3), P< 0.0001, respectively. CONCLUSION: We report that prior MI at a young age significantly increases SCD incidence from 4.1 to 305.0 per 100,000 person-years. Myocardial infarction is furthermore correlated with SCD and all-cause mortality with HR of 55.5 and 8.3, respectively.