Proarrhythmic drugs, drug levels, and polypharmacy in victims of sudden arrhythmic death syndrome: An autopsy-based study from Denmark

BACKGROUND

Sudden arrhythmic death syndrome (SADS), characterized by an unknown or inconclusive cause of death at autopsy, together with a negative or non-lethal toxicology screening, is the most common cause of sudden cardiac death (SCD) in victims under the age of 35. The complete causality of SADS remains unclear, with drugs being a potential risk factor.

OBJECTIVE

To describe the toxicological profiles of SADS victims, focusing on proarrhythmic drugs, drug levels, and polypharmacy.

METHODS

All deaths in Denmark from 2000-2019 aged 1-35 years and 2007-2019 aged 36-49 years were examined through death certificates, national registries, and autopsy reports with toxicology screenings. We investigated all sudden unexpected death victims with an autopsy performed, and where cause of death was unknown or inconclusive, including negative or non-lethal drug findings (SADS).

RESULTS

We identified 477 SADS victims; 313 (66%) had a positive toxicology screening (adjudicated non-lethal), with an average of 2.8 drugs/case. More than half of the SADS victims with a positive toxicology screening had QT-prolonging or brugadogenic drugs present. Polypharmacy was present in 66%, psychotropic polypharmacy in 37%, and QT-prolonging polypharmacy in 22%, with the most frequent overall and QT-prolonging drug combination being an antipsychotic and a psychoanaleptic drug. QT-prolonging drugs were more often present at suprapharmacological levels than non-QT-prolonging drugs.

CONCLUSION

A majority of the SADS population had a positive toxicology, with a notably large proportion having proarrhythmic drugs and polypharmacy. This highlights the need for future focus on drugs as a risk factor for SADS.

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.

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.

A multidisciplinary guideline-based approach to improving the sudden cardiac arrest care pathway: The Copenhagen framework

Although recommended in the European Resuscitation Council (ERC) and European Society of Intensive Care Medicine (ESICM) Guidelines, a framework for delivering post-cardiac arrest care in a systematic manner in dedicated high-volume cardiac arrest centers is lacking in the existing literature. To our knowledge, the Copenhagen Framework is the only established framework of its kind. The framework comprises management of out-of-hospital cardiac arrest (OHCA) survivors, and follow-up, and rehabilitation. The framework also incorporates research projects on cardiac arrest survivors and their close family members. The overall aim of this paper is to describe a framework made in order to bridge the gaps between international recommendations and delivering high-quality post-resuscitation clinical care, improving the continuity of care for OHCA survivors, access to post-CA rehabilitation, a seamless transition to everyday life, and ultimately patient outcomes in the future.

The ROCK trial-a multidisciplinary Rehabilitation intervention for sudden Out-of-hospital Cardiac arrest survivors focusing on return-to-worK: a pragmatic randomized controlled trial protocol

INTRODUCTION

Most cardiac arrest survivors are classified with mild to moderate cognitive impairment; roughly, 50% experience long-term neurocognitive impairment. Postarrest challenges complicate participation in society and are associated with social issues such as failure to resume social activities and impaired return to work. The effectiveness of rehabilitation interventions for out-of-hospital cardiac arrest survivors are sparsely described, but the body of evidence describes high probabilities of survivors not returning to work, returning to jobs with modified job descriptions, returning to part-time employment, and often in combination with extensive unmet rehabilitation needs. Hence, there is a need to develop and test a pragmatic individual targeted intervention to facilitate return to work (RTW) in survivors of OHCA. The overall aim of the ROCK trial is to evaluate the effectiveness of a comprehensive individually tailored multidisciplinary rehabilitation intervention for survivors of OHCA on RTW compared to usual care.

METHODS AND ANALYSIS

The ROCK trial is a two-arm parallel group multicentre investigator-initiated pragmatic randomized controlled superiority trial with primary endpoint measured 12 months after the cardiac arrest. Adult survivors who were part of the labour force prior to the OCHA and had at least 2 years until they are qualified to receive retirement state pensions are eligible for inclusion. Survivors will be randomized 1:1 to usual care group or usual care plus a comprehensive tailored rehabilitation intervention focusing on supporting RTW. After comprehensive assessment of individual rehabilitation needs, the intervention is ongoingly coordinated within a multidisciplinary rehabilitation team, and the intervention can be delivered for up until 12 months. Data for the primary outcome will be obtained from the national register on social transfer payments. The primary outcome will be analysed using logistic regression assessing RTW status at 12 months adjusting for the intervention and age at OHCA, sex, marital status, and occupation prior to OHCA.

DISCUSSION

The ROCK trial is the first RCT to investigate the effectiveness of a rehabilitation intervention focusing on return to work after cardiac arrest.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05173740. Registered on May 2018.

Primary myocardial fibrosis - a distinct entity characterized by heterogeneous histology

Primary myocardial fibrosis (PMF), defined as myocardial fibrosis in the absence of identifiable causes, may represent a common alternative phenotype in various cardiomyopathies and contribute to sudden cardiac death (SCD). No previous definitions of histopathological characteristics exist for PMF. We aimed to evaluate whether common features of fibrosis could be identified. PMF cases (n = 28) were selected from the FinGesture cohort consisting of 5,869 SCD victims that underwent a medicolegal autopsy. Twelve trauma controls and 10 ischemic heart disease cases were selected as reference groups. Further 3 PMF cases and 5 ischemic heart disease cases from autopsies performed in the University of Copenhagen, Denmark, were selected for a validation substudy. Relative area of fibrosis, amount of diffuse and perivascular fibrosis, and location of fibrosis were assessed from left ventricle myocardial samples stained with Masson trichrome. Further evaluations were performed with alpha-smooth muscle actin (α-SMA), vimentin, and CD68 stainings. Mean relative area of fibrosis was 5.8 ± 10.7%, 1.0 ± 0.7%, and 7.0 ± 7.4% in PMF, trauma controls, and ischemic cases, respectively. Fibrosis in the PMF group was mostly located in other sites than the endocardium. Most cases with fibrosis had vimentin-positive but α-SMA-negative stromal cells within fibrotic areas. Histopathologically, PMF represents a heterogeneous entity with variable fibrotic lesions affecting the whole myocardium and a suggested significant role of fibroblasts. These findings may bring validation to PMF being a common manifestation of cardiomyopathies. Evidently, PMF stands out as a particular entity demanding special attention as a cause of SCD.

Differences among young unwitnessed sudden cardiac death, according to time from last seen alive: Insights from a 15-year nationwide study

BACKGROUND

More than half of all sudden cardiac deaths (SCDs) are unwitnessed, but the composition of the unwitnessed SCD population is poorly described.

OBJECTIVE

The purpose of this study was to compare clinical and autopsy characteristics of young unwitnessed SCD subjects, based on the time from last contact to being found dead.

METHODS

All unwitnessed SCD subjects aged 1-35 years in Denmark from 2000-2014 identified through a multisource approach were included. Time from last seen alive to being found dead was dichotomized to <1 hour or 1-24 hours. Clinical characteristics and autopsy results were compared, and predictors of autopsy were assessed by logistic regression.

RESULTS

Of 440 unwitnessed SCD subjects, 366 (83%) had not been seen alive within 1 hour of being found dead. Comorbidities differed between the groups, with more epilepsy (17% vs 5%) and psychiatric diseases (13% vs 7%) in the 24-hour group. Patients in the 24-hour group died more frequently during sleep (64% vs 23%), the autopsy rate was higher (75% vs 61%), and deaths were more often unexplained after autopsy (69% vs 53%). Having been seen within 1 hour of death independently decreased the chance of being autopsied (odds ratio 0.51; 95% confidence interval 0.27-1.00; P = .0497).

CONCLUSION

The majority of unwitnessed SCD subjects had not been seen alive within 1 hour of being found dead. Clinical- and autopsy-related characteristics differed between the 2 groups. Differences were mainly attributable to death-related circumstances and comorbidities. Excluding SCD cases not seen alive within 1 hour of being found dead would severely underestimate the burden of SCD.

The Lancet Commission to reduce the global burden of sudden cardiac death: a call for multidisciplinary action

Despite major advancements in cardiovascular medicine, sudden cardiac death (SCD) continues to be an enormous medical and societal challenge, claiming millions of lives every year. Efforts to prevent SCD are hampered by imperfect risk prediction and inadequate solutions to specifically address arrhythmogenesis. Although resuscitation strategies have witnessed substantial evolution, there is a need to strengthen the organisation of community interventions and emergency medical systems across varied locations and health-care structures. With all the technological and medical advances of the 21st century, the fact that survival from sudden cardiac arrest (SCA) remains lower than 10% in most parts of the world is unacceptable. Recognising this urgent need, the Lancet Commission on SCD was constituted, bringing together 30 international experts in varied disciplines. Consistent progress in tackling SCD will require a completely revamped approach to SCD prevention, with wide-sweeping policy changes that will empower the development of both governmental and community-based programmes to maximise survival from SCA, and to comprehensively attend to survivors and decedents' families after the event. International collaborative efforts that maximally leverage and connect the expertise of various research organisations will need to be prioritised to properly address identified gaps. The Commission places substantial emphasis on the need to develop a multidisciplinary strategy that encompasses all aspects of SCD prevention and treatment. The Commission provides a critical assessment of the current scientific efforts in the field, and puts forth key recommendations to challenge, activate, and intensify efforts by both the scientific and global community with new directions, research, and innovation to reduce the burden of SCD worldwide.

Severity of Brugada syndrome disease manifestation and risk of new-onset depression or anxiety: a Danish nationwide study

AIMS

Reduced psychological health is associated with adverse patient outcomes and higher mortality. We aimed to examine if a Brugada syndrome (BrS) diagnosis and symptomatic disease presentation were associated with an increased risk of new-onset depression or anxiety and all-cause mortality.

METHODS AND RESULTS

All Danish patients diagnosed with BrS (2006-2018) with no history of psychiatric disease and available for ≥6 months follow-up were identified using nationwide registries and followed for up to 5 years after diagnosis. The development of clinical depression or anxiety was evaluated using the prescription of medication and diagnosis codes. Factors associated with developing new-onset depression or anxiety were determined using a multivariate Cox proportional hazards regression model. Disease manifestation was categorized as symptomatic (aborted cardiac arrest, ventricular tachycardia, or syncope) or asymptomatic/unspecified at diagnosis. A total of 223 patients with BrS and no history of psychiatric disease were identified (72.6% male, median age at diagnosis 46 years, 45.3% symptomatic). Of these, 15.7% (35/223) developed new-onset depression or anxiety after BrS diagnosis (median follow-up 5.0 years). A greater proportion of symptomatic patients developed new-onset depression or anxiety compared with asymptomatic patients [21/101 (20.8%) and 14/122 (11.5%), respectively, P = 0.08]. Symptomatic disease presentation (HR 3.43, 1.46-8.05) and older age (lower vs. upper tertile: HR 4.41, 1.42-13.63) were significantly associated with new-onset depression or anxiety. All-cause mortality in this group of patients treated according to guidelines was low (n = 4, 1.8%); however, 3/4 developed depression or anxiety before death.

CONCLUSION

Approximately, one-sixth of patients with BrS developed new-onset depression or anxiety following a diagnosis of BrS. Symptomatic BrS disease manifestation was significantly associated with new-onset depression or anxiety.

Bundle branch block in cardiac arrest survivors without ischemic heart disease

Aims

Cardiac arrest (CA) survivors with left/right bundle branch block (LBBB/RBBB) and no ischemic heart disease (IHD) have not been previously characterized. The aim of this study was to describe heart failure, implantable cardioverter defibrillator (ICD) therapy and mortality in this population.

Methods

Between 2009 and 2019 we consecutively identified all CA survivors with a consistent bundle branch block (BBB) defined as a QRS ≥ 120 ms, who had a secondary prophylactic ICD implanted. Patients with congenital and ischemic heart disease (IHD) were excluded.

Results

Among 701 CA-survivors who survived to discharge and received an ICD, a total of 58 (8%) were free from IHD and had BBB; 46 (79%) had LBBB, 10 (17%) had RBBB and 2 (3%) had non-specific BBB (NSBBB). The prevalence of LBBB was 7%. Pre-arrest ECG were available in 34 (59%) patients; 20 patients (59%) had LBBB, 6 (18%) had RBBB, 2 (6%) had NSBBB, 1 had (3%) incomplete LBBB, and 4 (12%) without BBB. At discharge, patients with LBBB had a significantly lower left ventricular ejection fraction (LVEF) than patients with other types of BBB, p < 0.001. During follow-up, 7 (12%) died after a median of 3.6 years (IQR: 2.6-5.1) with no difference between BBB subtypes.

Conclusion

We identified 58 CA-survivors with BBB and no IHD. The prevalence of LBBB among all CA-survivors was high, 7%. During CA hospitalization LBBB patients presented with a significantly lower LVEF than patients with other types of BBB (P < 0.001). ICD treatment and mortality did not differ between BBB subtypes during follow-up.

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.

Causes of sudden cardiac death according to age and sex in persons aged 1-49 years

BACKGROUND

Knowledge of causes of sudden cardiac death (SCD) according to age is important in clinical decision making and to lower the risk of SCD in family members of the deceased.

OBJECTIVE

The purpose of this study was to report overall and sex-stratified causes of SCD according to age in persons aged 1-49 years.

METHODS

The study population consisted of all persons in Denmark aged 1-35 years in 2000-2009 and 36-49 years in 2007-2009, which equals 27.1 million person-years. Danish death certificates, discharge summaries, autopsy reports, and data from nationwide registries were used to identify all SCD cases. The SCD cases were divided into 5-year age groups.

RESULTS

In the 10-year study period, there were 14,294 deaths, of which 1362 (10%) were classified as SCD. Potentially inherited cardiac disease accounted for a high proportion (43%-78%) of autopsied SCD in all age groups. A significant proportion (19%-54%) of SCD was caused by sudden arrhythmic death syndrome in all age groups. Autopsy rates in both sudden unexpected death cases and SCD cases declined significantly with increasing age (74% in the youngest age group vs 35% in the oldest).

CONCLUSION

The proportion of SCD cases that were identified with a potentially inherited cardiac disease postmortem was high in all studied age groups, while autopsy rates in sudden and unexpected death cases declined markedly with increasing age. Our findings indicate that diagnoses of inherited heart disease are likely missed in some SCD cases, along with the opportunity for treatment and prevention in surviving relatives.

The Utility of Sodium Channel Provocation in Unexplained Cardiac Arrest Survivors and Electrocardiographic Predictors of Ventricular Fibrillation Recurrence

BACKGROUND

The implications of a drug-induced type 1 Brugada ECG pattern following sodium channel blocker provocation (SCBP) are not fully understood.

METHODS

Baseline clinical and ECG data were obtained from consecutive unexplained cardiac arrest survivors undergoing SCBP at 3 centers. A further 15 SCBP positive (SCBP+) unexplained cardiac arrest survivors were recruited from 3 additional centers to explore ventricular fibrillation recurrence.

RESULTS

A total of 121 consecutive unexplained cardiac arrest survivors underwent SCBP. The yield of the drug-induced type 1 Brugada ECG pattern was 17%. A baseline type 2/3 Brugada pattern (T2/3BP) (adjusted odds ratio, 19.36 [2.74-136.61]; P=0.003) and PR interval (odds ratio, 1.03 [1.01-1.05] per ms; P=0.017) were independent predictors of SCBP+ response. A pathogenic SCN5A variant was identified in 36% of the SCBP+ group versus 0% in the SCBP- group (P<0.001). Amongst SCBP+ patients, a spontaneous type 1 Brugada pattern was identified in 19% during follow up and in 24% a type 1 Brugada pattern was identified in a relative. Prior syncope (adjusted hazard ratio, 3.83 [1.36-10.78]; P=0.011) and the presence of global early repolarization (hazard ratio, 7.91 [3.22-19.44]; P<0.001) were independent predictors of 5-year ventricular fibrillation recurrence. There was a nonsignificant trend toward greater 5-year ventricular fibrillation recurrence in the SCBP- group (23/95 [24%] versus 3/34 [9%]; P=0.055).

CONCLUSIONS

The yield of the drug-induced type 1 Brugada ECG pattern in consecutive unexplained cardiac arrest survivors undergoing SCBP is 17%. A baseline T2/3BP and PR interval were independent predictors of the drug-induced type 1 Brugada ECG pattern. Greater heritability of BrS phenotype in this group was evidenced by a greater prevalence of pathogenic SCN5A variants and relatives with a type 1 Brugada pattern. A history of prior syncope and the presence of global early repolarization were independent predictors of ventricular fibrillation recurrence.

Effect of time on characterics and cause of death in unwitnessed, young sudden cardiac death cases

Introduction

Around 50% of all sudden cardiac death (SCD) cases are unwitnessed. According to the World Health Organization's definition of sudden cardiac death, any unwitnessed death is considered SCD if the person was last seen alive and well within 24 hours of death and with confirmed or suspected cardiac cause of death. The length of this timespan has been debated, as the nature of death in unwitnessed cases is less certain compared to witnessed cases. The effect of time on the composition of the group of unwitnessed SCD cases has not previously been assessed.

Purpose

This study aimed to compare clinical characteristics and causes of death among unwitnessed SCD cases last seen alive within 1 hour or 24 hours.

Methods

This nationwide, retrospective study conducted in Denmark included all deceased persons aged 1–35 from 2000–2014. The highly descriptive Danish death certificates were utilized to identify all sudden and unexpected deaths. Through subsequent examination of autopsy reports and discharge summaries, we identified all SCD cases. In addition, witnessed status and time since last seen alive (1 vs. 24 hours) were recorded. Information on comorbidities was collected from the Danish Health Registries.

Results

During the 15-year study period, we identified 857 SCD. Of these, 353 (41%) were witnessed, and 441 (51%) were unwitnessed; 62 (7%) cases had unknown witnessed status. Among the unwitnessed SCD, 75 (17%) were last seen alive within 1 hour, and the remaining 366 (83%) were seen alive within 24 hours.

Comparison of clinical characteristics and cause of death revealed few but distinct differences. Cases seen within 1 hour were of male predominance (82% vs. 65%, p=0.005). The comorbidity burden was similar, except for epilepsy which was significantly more prevalent among the group last seen alive within 24 hours. Circumstances regarding death also differed among the groups: Cases seen alive within 1 hour were more often awake at the time of death (72% vs. 36%, p&lt;0.001) when compared to cases seen alive within 24 hours, and they were less often autopsied (61% vs. 75%, p=0.02). Among autopsied cases, structural heart disease was more often the cause of death among persons last seen alive within 1 hour (58% vs. 40%, p=0.02). In both groups. The most common cause of death was sudden unexpected death, but the proportion was significantly higher in the 24-hour group (60% vs 42%, p=0.03). Arrhythmogenic cardiomyopathy and thoracic aortic dissection were significantly more prevalent among cases seen within 1 hour (11% vs. 3%, p=0.002 for both).

Conclusions

In this 15-year nationwide study of SCD in Denmark, we found few, marked differences in cause of death and clinical characteristics between unwitnessed SCD last seen alive within 1 and 24 hours. Male sex predominated in cases seen within 1 hour, and the autopsy rate was significantly lower. In the autopsied cases structural heart disease was more common in cases seen alive within 1 hour.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): University of Copenhagen

Myocardial scarring and recurrence of ventricular arrhythmia in patients surviving a ventricular fibrillation out of hospital cardiac arrest

Introduction

Prediction of ventricular arrhythmia recurrence in survivors of ventricular fibrillation out of hospital cardiac arrest (VF-OHCA) is important, but currently difficult. Risk of recurrence may be related to presence of myocardial scarring and dedicated late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) software allows for characterization of left ventricular scarring, including differentiation between core, border zone (BZ) and BZ channels that represent potential electrical circuits of slow conductivity responsible for ventricular arrhythmic events.

Purpose

Our study aims to characterize myocardial scarring as defined by LGE-CMR in survivors of a VF-OCHA and investigate its potential role for the risk of new ventricular arrhythmia.

Methods

Between 2018 and 2021, a total of 130 VF-OHCA patients had CMR, of which we included 28 patients with LGE-CMR before ICD implantation for secondary prevention. A total of 15 (54%) patients had signs of acute or chronic ischemic heart disease (IHD); and 13 (46%) patients had arrhythmogenic cardiomyopathy (ACM). Scar tissue including core, BZ and BZ channels were automatically detected by specialized investigational software. To differentiate BZ from healthy tissue and BZ from core, thresholds of 40% ± 5% and 60% ± 5% of the maximum signal intensity were applied. A BZ channel in the LGE-CMR reconstruction was defined as a continuous corridor of BZ between 2 core areas or between a core area and a valve annulus (Figure 1A+B).

Results

The median age was 56 years; 86% were men and the median left ventricular ejection fraction was 50±11%. A total of 16 (57%) patients had an inferior scar on LGE-CMR, and 8 (29%) patients with IHD were incompletely revascularized. After a median follow-up of 98 days, 9 (32%) patients (6/9 with IHD, including 5/6 incompletely revascularized; 3/9 with ACM) had recurrence of ventricular arrhythmia (6/9 monomorphic ventricular tachycardia (VT)). A significantly higher number of patients with BZ channels had recurrence of ventricular arrhythmia compared with patients without BZ channels (7/11 vs. 2/17; P=0.01) (Figure 2). The number of BZ channels (3±1 vs. 2±1; P=0.13); scar mass (21±8g vs. 14±11g; P=0.21); core mass (7±4g vs. 4±5g; P=0.14); and BZ mass (11±5g vs. 9±7g; P=0.42) were insignificantly higher in patients with recurrent ventricular arrhythmia compared with patients without.

Conclusion

Borderzone channels analyzed by LGE-CMR were associated with subsequent recurrence of ventricular arrhythmia in patients with out of hospital cardiac arrest caused by ventricular fibrillation.

Funding Acknowledgement

Type of funding sources: None.

Duration of Resuscitation and Long-Term Outcome After In-Hospital Cardiac Arrest: A Nationwide Observational Study

BACKGROUND

Prior studies have investigated the association between duration of resuscitation and short-term outcomes following in-hospital cardiac arrest (IHCA). However, it remains unknown whether there is an association between duration of resuscitation and long-term survival and functional outcomes.

METHOD

We linked data from the Danish in-hospital cardiac arrest registry with nationwide registries and identified 8,727 patients between 2013 and 2019. Patients were stratified into four groups (A-D) according to quartiles of duration of resuscitation. Standardized average probability of outcomes was estimated using logistic regression.

RESULTS

Of 8,727 patients, 53.1% (n=4,604) achieved return of spontaneous circulation. Median age was 74 (1^st-3^rd quartile [Q1-Q3] 65-81 years) and 63.1% were men. Among all IHCA patients the standardized 30-day survival was 62.0% (95% CI 59.8%-64.2%) for group A (< 5 minutes), 32.7% (30.8%-34.6%) for group B (5-11 minutes), 14.4% (12.9%-15.9%) for group C (12-20 minutes) and 8.1% (7.0%-9.1%) for group D (21 minutes or more). Similarly, 1-year survival was also highest for group A (50.4%; 48.2%-52.6%) gradually decreasing to 6.6% (5.6%-7.6%) in group D. Among 30-day survivors, survival without anoxic brain damage or nursing home admission within one-year post-arrest was highest for group A (80.4%; 78.2%-82.6%), decreasing to 73.3% (70.0%-76.6%) in group B, 67.2% (61.7%-72.6%) in group C and 73.3% (66.9%-79.7%) in group D.

CONCLUSION

Shorter duration of resuscitation attempt during an IHCA is associated with higher 30-day and 1-year survival. Furthermore, we found that the majority of 30-day survivors were still alive 1-year post-arrest without anoxic brain damage or nursing home admission despite prolonged resuscitation.

Exercise Testing Using Sprint Protocol vs Bruce Protocol in Catecholaminergic Polymorphic Ventricular Tachycardia

We present the case of a relative of a patient with catecholaminergic polymorphic ventricular tachycardia. This relative underwent a standard (Bruce) exercise stress test (EST), which had normal results. He then underwent our modified “sprint” EST, with positive results. This report underlines how the sprint EST may provoke arrhythmias better than the standard Bruce EST. (Level of Difficulty: Advanced.)

Workforce attachment after a congenital long QT syndrome diagnosis: a Danish nationwide study

Objective

To examine workforce attachment among patients with congenital long QT syndrome (cLQTS) following diagnosis and identify factors associated with workforce attachment.

Methods and results

In this nationwide cohort study, all patients diagnosed with cLQTS in Denmark between 1996 and 2016 aged 18–60 years at diagnosis were identified using nationwide registries. Patients attached to the workforce at diagnosis were included. Attachment to the workforce 1 year after cLQTS diagnosis was examined and compared with a background population matched 1:4 on age, sex and employment status. Multiple logistic regression was performed to identify factors associated with 1-year workforce detachment among patients with cLQTS. 298 patients fulfilled the inclusion criteria. Six months after cLQTS diagnosis, 90.9% of patients with cLQTS were attached to the workforce compared with 95.0% in the background population (p=0.006 for difference). One year after diagnosis, 93.3% of patients with cLQTS were attached to the workforce compared with 93.8% in the background population (p=0.26). Among patients with cLQTS, a severe cLQTS disease manifestation was associated with workforce detachment 1 year after diagnosis (compared with asymptomatic patients; aborted cardiac arrest OR 20.4 (95% CI, 1.7 to 249.9); ventricular tachycardia/syncope OR 10.9 (95% CI, 1.1 to 110.5)). No other associated factors were identified.

Conclusions

More than 90% of patients with cLQTS remained attached to the workforce 1 year after diagnosis, which was similar to a matched background population. Patients with a severe cLQTS disease manifestation were less likely to be attached to the workforce 1 year after diagnosis.

[Sudden unexpected death in epilepsy]

Sudden and unexpected death is defined as sudden death without any obvious cause and where the person was seen in habitual conditions within the last 24 hours before death. Persons with epilepsy have a 34-fold increased risk of dying suddenly and unexpectedly compared with the background population. In persons with epilepsy these deaths are referred to as sudden unexpected death in epilepsy (SUDEP). This review finds that the risk is highest in younger adults, and SUDEP is the second leading cause of death in persons with epilepsy aged 1-49 years. Good seizure control is important in the prevention of SUDEP.

More than half of all sudden cardiac deaths occur in persons without a history of cardiovascular disease: A study of 54,028 deaths in Denmark

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): Copenhagen University Hospital, Rigshospitalet

Background

Sudden cardiac death (SCD) is a major public health problem accounting for a large proportion of global mortality. Previous studies suggest that SCD often occurs in the general population in persons not previously diagnosed with cardiovascular disease. It is evidently challenging to identify high-risk persons in an overwhelmingly large population of mainly healthy individuals and studies are needed to further characterize these SCD cases.

Purpose

To estimate SCD burden in patients not previously diagnosed with cardiovascular disease and to characterize these SCD cases.

Methods

All deaths in Denmark (population of 5.5 million) in 2010 were manually reviewed case-by-case. Autopsy reports, death certificates, and information from nationwide health registries were systematically examined to identify all SCD in 2010. The Danish National Patient Register contains information on all in- and outpatient activities at Danish hospitals and emergency departments and was used to identify all SCD cases with a previous cardiovascular diagnosis.

Results

There were 54,028 deaths in Denmark in 2010, of which 6,867 (13%) were categorized as SCD. Overall incidence rate of SCD was 124 (95%-CI: 121-127) per 100,000 person-years. Of all SCD, 59% were not diagnosed with cardiovascular disease prior to death. SCD incidence in persons with and without a history of cardiovascular disease was 790 (95%-CI: 762-820) and 78 (95%-CI: 75-80) per 100,000 person-years, respectively. This corresponds to an incidence rate ratio of 10 (95%-CI: 10-11). SCD cases with no previously diagnosed cardiovascular diseases were younger (median age 75 vs. 80 years, p&lt;0.001), more often female (45 vs. 42%, p=0.019), and on average had a lower household income (p=0.002) (Table 1). SCD cases not diagnosed with cardiovascular disease prior to death in general had fewer comorbidities, except for psychiatric diseases, which were more common in the undiagnosed group (Table 1).

Conclusion

In this large and nationwide study of all SCD in Denmark in 2010, more than half of all SCD occurred in persons without a history of cardiovascular disease. This suggests that SCD is often first manifestation of disease. We currently do not have accurate tools for SCD risk stratification in the general population and future research is needed to identify modifiable and easily measured risk factors of SCD in the general population.

Untargeted toxicology in sudden cardiac arrest victims

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Union’s Horizon 2020 research and innovation programme to J.T.-H under acronym ESCAPE-NET

Background

Sudden cardiac arrest (SCA) is a major public health challenge and is associated with poor outcomes. Many drugs are known to increase risk of arrythmias and ultimately sudden cardiac death. To our knowledge an untargeted toxicological analysis has not previously been performed in an initially resuscitated SCA cohort.

Purpose

We aimed to determine the qualitative and quantitative drug composition present in SCA patients by using forensic toxicological analytical chemistry of all illicit, non-prescription and prescribed drugs, and further investigate whether these drugs are in therapeutic levels or overdosed and to correlate the clinical findings with the toxicology results.

Methods

We performed a prospective single-tertiary-center study and included all SCA victims (aged 18-90 years) admitted to our cardiac intensive care unit, between February 2019 to November 2019 (Figure 1). Traumatic and overt overdose related SCA were not included in the study. Drugs used during resuscitation and administered prior to sample collection were identified in each patient and excluded.

Results

We prospectively identified 85 all-cause SCA patients with a median age of 60 years (IQR: 53-71) and male predominance (80%). The majority had a shockable rhythm as first rhythm (95%). The major cause of cardiac arrest was acute and chronic ischemia (56/77, 66%), followed by cardiomyopathy (9/77, 12%), idiopathic ventricular fibrillation (8/77, 10%), bradycardia (2/77, 2.6%), primary arrhythmia (1/77, 1.3%), other (1/77, 1.3%). The remaining 8 patients (9.4%) died prior to diagnosis.

A positive toxicology was identified in 67 patients (79%) with a total of 218 detected drugs. The most frequent drugs were mild analgesics (32/85, 38%), beta-blockers (21/85, 25%) and ACE-inhibitors/ARB (20/85, 24%). A total of 9 (11%) patients had one or more potentially abusable drugs detected, with the most common being opioid agonists in 5 patients (Figure 2). Importantly, all drugs were found at sub-therapeutic or therapeutic concentrations. None had overdose concentrations. Moreover, polypharmacy was common and a median of 2 drugs (IQR: 1-4) were detected (excluding caffeine that was detected in 83 patients).

Conclusion

We found that the majority had drugs detected, and polypharmacy is displayed in a considerable proportion. Potentially abusive drugs were encountered in 11%. However, we did not identify any occult overdose related cardiac arrests among all resuscitated SCA patients. In our setting, toxicological screening in cardiac arrest patients who is not obviously overdosed is excessive.

Nationwide study of mortality and sudden cardiac death in young persons diagnosed with chronic kidney disease

AIMS

The aim of this study was to compare short- and long-term risk of sudden cardiac death (SCD) among persons aged 18-49 years with and without chronic kidney disease (CKD).

METHODS AND RESULTS

Using Danish nationwide health registries, all persons aged 18-49 years diagnosed with earlier stages of CKD or chronic kidney failure from 1 July 1995 through 2009 were identified. Non-exposed subjects matched on sex and birth-year were identified. All SCD in the Danish population aged 18-49 years in 2000-2009 have previously been identified using information from the Danish nationwide health registries, death certificates, and autopsy reports. In total, 9308 incident cases of earlier stage CKD and 1233 incident cases of chronic kidney failure were included. Among patients with earlier stage CKD, the absolute risk of SCD 1, 5, and 10 years after diagnosis was 0.14%, 0.37%, and 0.68%, respectively. Compared with age- and sex-matched subjects the corresponding relative risk (RR) was 20.3 [95% confidence interval (CI) 8.4-48.8], 7.1 (95% CI 4.2-12.0), and 6.1 (95% CI 3.8-9.7), respectively. Among patients with chronic kidney failure, the absolute 1-, 5-, and 10-year risk of SCD was 0.17%, 0.56%, and 2.07%, respectively. The corresponding RR was 12.5 (95% CI 1.4-111.6), 7.9 (95% CI 2.3-27.0), and 10.1 (95% CI 4.5-22.6).

CONCLUSION

Persons with earlier stage CKD and chronic kidney failure had increased risk of SCD compared with the background population with a 6- to 20-fold increased risk of SCD. These findings underline the importance of early cardiovascular risk monitoring and assessment in persons with CKD.

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 Na_V1.5, 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 Na_V1.5 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.

Rare Variation in Drug Metabolism and Long QT Genes and the Genetic Susceptibility to Acquired Long QT Syndrome

BACKGROUND

Acquired long QT syndrome (aLQTS) is a serious unpredictable adverse drug reaction. Pharmacogenomic markers may predict risk.

METHODS

Among 153 aLQTS patients (mean age 58 years [range, 14-88], 98.7% White, 85.6% symptomatic), computational methods identified proteins interacting most significantly with 216 QT-prolonging drugs. All cases underwent sequencing of 31 candidate genes arising from this analysis or associating with congenital LQTS. Variants were filtered using a minor allele frequency <1% and classified for susceptibility for aLQTS. Gene-burden analyses were then performed comparing the primary cohort to control exomes (n=452) and an independent replication aLQTS exome sequencing cohort.

RESULTS

In 25.5% of cases, at least one rare variant was identified: 22.2% of cases carried a rare variant in a gene associated with congenital LQTS, and in 4% of cases that variant was known to be pathogenic or likely pathogenic for congenital LQTS; 7.8% cases carried a cytochrome-P450 (CYP) gene variant. Of 12 identified CYP variants, 11 (92%) were in an enzyme known to metabolize at least one culprit drug to which the subject had been exposed. Drug-drug interactions that affected culprit drug metabolism were found in 19% of cases. More than one congenital LQTS variant, CYP gene variant, or drug interaction was present in 7.8% of cases. Gene-burden analyses of the primary cohort compared to control exomes (n=452), and an independent replication aLQTS exome sequencing cohort (n=67) and drug-tolerant controls (n=148) demonstrated an increased burden of rare (minor allele frequency<0.01) variants in CYP genes but not LQTS genes.

CONCLUSIONS

Rare susceptibility variants in CYP genes are emerging as potentially important pharmacogenomic risk markers for aLQTS and could form part of personalized medicine approaches in the future.

OUP accepted manuscript

Patient-reported return-to-work and job functioning 6 and 12 months after hospital discharge and received rehabilitation interventions and unmet rehabilitation needs were explored in a consecutive population of out-of-hospital cardiac arrest survivors. Patients working prior to cardiac arrest were invited to participate in a telephone administered survey. Thirty-eight surveys were conducted and included for analysis, equivalent to a minimum response rate of 95%. Survivors of out-of-hospital cardiac arrest had extensive challenges returning to work. Six- and 12-months post-arrest, 58% and 45% were respectively on full time sick leave or working notably less (>10 h/week) and with extensive unmet rehabilitation needs.

Clinician Preimplementation Perspectives of a Decision-Support Tool for the Prediction of Cardiac Arrhythmia Based on Machine Learning: Near-Live Feasibility and Qualitative Study

Background

Artificial intelligence (AI), such as machine learning (ML), shows great promise for improving clinical decision-making in cardiac diseases by outperforming statistical-based models. However, few AI-based tools have been implemented in cardiology clinics because of the sociotechnical challenges during transitioning from algorithm development to real-world implementation.

Objective

This study explored how an ML-based tool for predicting ventricular tachycardia and ventricular fibrillation (VT/VF) could support clinical decision-making in the remote monitoring of patients with an implantable cardioverter defibrillator (ICD).

Methods

Seven experienced electrophysiologists participated in a near-live feasibility and qualitative study, which included walkthroughs of 5 blinded retrospective patient cases, use of the prediction tool, and questionnaires and interview questions. All sessions were video recorded, and sessions evaluating the prediction tool were transcribed verbatim. Data were analyzed through an inductive qualitative approach based on grounded theory.

Results

The prediction tool was found to have potential for supporting decision-making in ICD remote monitoring by providing reassurance, increasing confidence, acting as a second opinion, reducing information search time, and enabling delegation of decisions to nurses and technicians. However, the prediction tool did not lead to changes in clinical action and was found less useful in cases where the quality of data was poor or when VT/VF predictions were found to be irrelevant for evaluating the patient.

Conclusions

When transitioning from AI development to testing its feasibility for clinical implementation, we need to consider the following: expectations must be aligned with the intended use of AI; trust in the prediction tool is likely to emerge from real-world use; and AI accuracy is relational and dependent on available information and local workflows. Addressing the sociotechnical gap between the development and implementation of clinical decision-support tools based on ML in cardiac care is essential for succeeding with adoption. It is suggested to include clinical end-users, clinical contexts, and workflows throughout the overall iterative approach to design, development, and implementation.

Epilepsy-Related Mortality in Children and Young Adults in Denmark: A Nationwide Cohort Study

BACKGROUND AND OBJECTIVES

Mortality is increased in epilepsy, but the important issue is that a proportion of epilepsy-related death is potentially preventable by optimized therapy and needs therefore to be identified. A new systematic classification of epilepsy-related mortality has been suggested by Devinsky et al. in 2016 to identify these preventable deaths. We applied this classification to an analysis of premature mortality in persons with epilepsy younger than 50 years.

METHODS

The study was a population-based retrospective cohort of all Danish citizens with and without epilepsy aged 1-49 years during 2007-2009. Information on all deaths was retrieved from the Danish Cause of Death Registry, autopsy reports, death certificates, and the Danish National Patient Registry. The primary cause of death in persons with epilepsy was evaluated independently by three neurologist, one neuro-pediatrician, and two cardiologists. In case of uncertainty a pathologist was consulted. All deaths were classified as either epilepsy- or not-epilepsy-related, and the underlying causes or modes of death were compared between persons with and without epilepsy.

RESULTS

During the study period 700 deaths were identified in persons with epilepsy, and 440 (62.9%) of these were epilepsy-related, hereof, 169 (38%) directly related to seizures and 181 (41%) due to an underlying neurological disease. SUDEP accounted for 80% of deaths directly related to epilepsy. Aspiration pneumonia was the cause of death in 80% of cases indirectly related to epilepsy.Compared with the background population, persons with epilepsy had a nearly four-fold increased all-cause mortality (adjusted mortality hazard ratio of 3.95 [95% CI 3.64-4.27], p<0.0001) and a higher risk of dying from various underlying causes including alcohol-related conditions (hazard ratio of 2.91 [95% CI 2.23-3.80], p<0.0001) and suicide (hazard ratio of 2.10 [95% CI 1.18-3.73], p=0.01).

DISCUSSION

The newly proposed classification for mortality in persons with epilepsy was useful in an unselected nationwide cohort. It helped classifying unnatural causes of death as epilepsy-related or not, and it helped identifying potentially preventable deaths. The leading causes of premature mortality in persons younger than 50 years were related to epilepsy and were thus potentially preventable by good seizure control.

Sex differences in sudden cardiac death: a nationwide study of 54,028 deaths in Denmark

Background

Sudden cardiac death (SCD) is a leading cause of death. SCD is more common among males. In women SCD is, however, still the leading cause of death. The SCD epidemiology among women is less studied.

Purpose

The aim of this study was to examine how incidence rates, clinical characteristics and causes of SCD vary between males and females.

Methods

All deaths in Denmark in the 2010 (54,028) were included in the study. Autopsy reports, death certificates, discharge summaries and nationwide health registries were reviewed to identify cases of SCD. Sex and age specific SCD incidence rates in the general population were calculated, and age-adjusted clinical characteristics were compared using logistic regression.

Results

A total of 6,867 SCD cases were identified, of which 3,859 (56%) were males and 3,008 (44%) were females. Incidence rates increased with age and was higher for males across all age groups in the adult population. Average age of SCD was 71.3±14.3 years among males compared to 79.4±13.3 among females (mean ± standard deviation, p&lt;0.0001). The greatest difference in incidence between males and females was found among the 35–50-year group with an incidence rate ratio of 3.7 (95% confidence interval: 2.8–4.8). Although the males were younger, males more often had cardiovascular diseases and diabetes mellitus prior to SCD. Among autopsied cases, coronary artery disease (CAD) was the leading cause of death among both sexes. Structural causes of SCD, other than CAD, were more common among women (p&lt;0.01).

Conclusion

In this nationwide study of sex differences in SCD across all age groups, the differences in incidence rates between males and females were greatest among young adults and the middle-aged. Incidence rates of SCD among older females approached that of the male population, despite significantly more cardiovascular disease and diabetes mellitus in the male population in the 10 years prior to SCD.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Department of Cardiology, The Heart Centre, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark

[Cardiac arrest in a patient with long QT syndrome receiving androgen deprivation therapy]

This is a case report of a 72-year-old male with a newly diagnosed prostate cancer, who was treated with androgen deprivation therapy and anti-androgen. The patient was diagnosed with congenital long QT syndrome (LQTS), and a markedly worsening of the QT-prolongation was observed, after the hormonal therapy was initiated. He ultimately suffered an initially resuscitated cardiac arrest but did not survive to discharge. Pharmaceutical treatments in patients with LQTS should always be handled with caution, and if a treatment with a known or probable QT-prolonging drug is initiated, a cardiologist should be consulted.

Sex Disparities in Sudden Cardiac Death

The overall incidence of sudden cardiac death is considerably lower among women than men, reflecting significant and often under-recognized sex differences. Women are older at time of sudden cardiac death, less likely to have a prior cardiac diagnosis, and less likely to have coronary artery disease identified on postmortem examination. They are more likely to experience their death at home, during sleep, and less likely witnessed. Women are also more likely to present in pulseless electrical activity or systole rather than ventricular fibrillation or ventricular tachycardia. Conversely, women are less likely to receive bystander cardiopulmonary resuscitation or receive cardiac intervention post-arrest. Underpinning sex disparities in sudden cardiac death is a paucity of women recruited to clinical trials, coupled with an overall lack of prespecified sex-disaggregated evidence. Thus, predominantly male-derived data form the basis of clinical guidelines. This review outlines the critical sex differences concerning epidemiology, cause, risk factors, prevention, and outcomes. We propose 4 broad areas of importance to consider: physiological, personal, community, and professional factors.

Witnessed and unwitnessed sudden cardiac death: a nationwide study of persons aged 1-35 years

AIMS

The aim of this study is to compare clinical characteristics and causes of death among witnessed and unwitnessed sudden cardiac death (SCD) cases aged 1-35 years.

METHODS AND RESULTS

In this retrospective nationwide study, all deaths in persons aged 1-35 years in Denmark during 2000-09 were included (23.7 million person-years). Using the in-depth descriptive Danish death certificates and Danish nationwide registries, 860 cases of sudden, unexpected death were identified. Through review of autopsy reports and register data, we identified 635 cases of SCD of which 266 (42%) were witnessed and 326 (51%) were unwitnessed. In 43 cases (7%), witnessed status was missing. Clinical characteristics were overall similar between the two groups. We found a male predominance among unwitnessed SCD compared to witnessed SCD (71% and 62%, respectively, P-value 0.012), as well as more psychiatric comorbidity (20% and 13%, respectively, P-value 0.029). Unwitnessed SCD more often occurred during sleep whereas witnessed SCD more often occurred while the individual was awake and relaxed (P-value < 0.001). The autopsy rate among all SCD cases was 70% with no significant difference in autopsy rate between the two groups. Sudden unexplained death, which was the leading autopsy conclusion in both groups, was more frequent among unwitnessed SCD (P-value 0.001).

CONCLUSION

Several clinical characteristics and autopsy findings were similar between witnessed and unwitnessed SCD cases. Our data support the inclusion of both witnessed and unwitnessed cases in epidemiological studies of SCD cases aged 1-35 years, although the risk of misclassification is higher among unwitnessed and non-autopsied cases of SCD.

Remote Monitoring of the QT Interval and Emerging Indications for Arrhythmia Prevention

QT interval prolongation is a marker of increased risk for life-threatening arrhythmias, and needs to be promptly recognized. Many effective drugs, however, prolong QTc (QT interval corrected for heart rate) in genetically predisposed subjects. The possibility of remote monitoring and QTc measurement for up to 2 weeks, continuously providing physicians with real time data, allows life-saving interventions or changes in drug therapy. This applies especially to patients with the long QT syndrome and to those taking drugs blocking the IKr current and prolonging the QT interval. Patch monitors recording ECG traces continuously are available and contribute to effective arrhythmic prevention.

Diagnostic yield in victims of sudden cardiac death and their relatives

AIMS

International guidelines recommend cardiogenetic screening in families with sudden cardiac death (SCD) if the suspected cause is an inherited cardiac disease. The aim was to assess the diagnostic yield of inherited cardiac diseases in consecutively referred SCD families.

METHODS AND RESULTS

In this single-centre retrospective study, we consecutively included families referred to our tertiary unit between 2005 and 2018 for screening due to SCD. Following evaluation of premortem medical records and postmortem findings for the proband, the families underwent a guideline-based screening protocol. Relatives were followed and cardiovascular events registered. In total, 304 families with 695 relatives were included. In probands, mean age at death was 39 years (75% males) and in relatives mean age at screening was 35 years (47% males). The proband-diagnosis was established through autopsy findings (n = 89), genetic analyses (n = 7), or based on premortem findings (n = 21). In the remaining 187 families with borderline/no diagnosis in the proband, screening of relatives yielded a diagnosis in 26 additional families. In total, an inherited cardiac disease was identified in 143 out of 304 families (47%). In relatives, 73 (11%) were diagnosed. Arrhythmogenic right ventricular cardiomyopathy (n = 16) was the most common diagnosis. During follow-up (mean 5.5 years), a low rate of serious cardiac events was observed (no SCD events).

CONCLUSION

Forty-seven percent of SCD families were diagnosed. Eleven percent of the screened relatives received a definite diagnosis and were offered treatment according to guidelines. A low rate of serious cardiovascular events was observed among SCD relatives.

Nationwide burden of sudden cardiac death: A study of 54,028 deaths in Denmark

BACKGROUND

A large proportion of all deaths are sudden cardiac deaths (SCDs). Reliable estimates of nationwide incidence of SCD, however, are missing.

OBJECTIVES

The goals of this study were to estimate SCD burden across all age groups in Denmark and to compare it with the estimates of other common causes of death.

METHODS

All deaths in Denmark (population of 5.5 million) in 2010 were manually reviewed case by case. Autopsy reports, death certificates, and information from nationwide health registries were systematically examined to identify all SCD cases in 2010. According to the level of detail of the available information, all deaths were categorized as either non-SCD, definite SCD, probable SCD, or possible SCD.

RESULTS

There were 54,028 deaths in Denmark in 2010, of which 6867 (13%) were categorized as SCD (591 (9%) definite SCD, 1568 (23%) probable SCD, and 4708 (68%) possible SCD). The incidence rate of definite SCD was 11 (95% confidence interval 10-12) per 100,000 person-years. Including definite, probable, and possible SCD cases, the highest possible overall SCD incidence rate was 124 (95% confidence interval 121-127) per 100,000 person-years. Estimated SCD burden was similar to or greater than the estimates of all other common causes of death. Of all SCD cases, 49% were not diagnosed with cardiovascular disease before death.

CONCLUSION

SCD accounted for up to 13% of all deaths. Almost half of all SCD cases occurred in persons without a history of cardiovascular disease. Consequently, the optimization of risk stratification and prevention of SCD in the general population should be given high priority.

Motor and process skills in activities of daily living in survivors of out-of-hospital cardiac arrest: a cross-sectional study at hospital discharge

AIMS

An individuals' ability to perform basic activities of daily living (ADL) is said to be one of the strongest predictors of performance ability and independent living within the community. The Assessment of Motor and Process Skills (AMPS) tool was designed to assess global functional level during ADL by investigating motor and process skills. The purpose of this study was to assess ADL performance ability by investigating motor and process skills in a consecutive cohort of adult survivors of out-of-hospital cardiac arrest at the time of discharge from hospital.

METHODS AND RESULTS 

This cross-sectional study uses data from a prospective cohort of cardiac arrest survivors admitted to the Copenhagen University Hospital, Rigshospitalet. The specific data used in this study were obtained at the time of the days or the day before hospital discharge. Adult survivors of out-of-hospital cardiac arrest due to cardiac causes were eligible for inclusion. Assessment of Motor and Process Skills was used to assess ADL performance ability by investigating motor and process skills. The ADL ability of 61 individuals was assessed. The mean ADL ability measures recorded were AMPS process 1.40 logits (0.48) and AMPS motor 1.82 logits (0.40). Based on the dichotomized AMPS results, 23% were most likely to need assistance to live independently in the community.

CONCLUSION 

Performance ability during ADL revealed difficulty in the performance of process skill and an increased need for rehabilitation among survivors of out-of-hospital cardiac arrest at the time of hospital discharge.

Low Birth Weight Increases the Risk of Sudden Cardiac Death in the Young: A Nationwide Study of 2.2 Million People

Background Sudden cardiac death (SCD) constitutes a major health problem worldwide. We investigated whether birth weight (BW), small for gestational age (SGA), and large for gestational age are associated with altered risk of SCD among the young (aged 1-36 years). Methods and Results We included all people born in Denmark from 1973 to 2008 utilizing the Danish Medical Birth Register. All SCDs in Denmark in 2000 to 2009 have previously been identified. We defined 5 BW groups, SGA, and large for gestational age as exposure and SCD as the outcome. We estimated the age-specific relative risk of SCD with 95% CI. Additionally, we investigated if SGA and large for gestational age are associated with pathological findings at autopsy. The study population for the BW analyses comprised 2 234 501 people with 389 SCD cases, and the SGA and large for gestational age analyses comprised 1 786 281 people with 193 SCD cases. The relative risk for SCD was 6.69 for people with BW between 1500 and 2499 g (95% CI, 2.38-18.80, P<0.001) and 5.89 for people with BW ≥4500 g (95% CI, 1.81-19.12, P=0.003) at age 5 years. BW 2500 to 3400 g was the reference group. Compared with an appropriate gestational age, the relative risk for SGA was 2.85 (95% CI, 1.35-6.00, P=0.006) at age 10 years. For the autopsied cases, the relative risk of sudden arrhythmic death syndrome at age 5 years was 4.19 for SGA (95% CI, 1.08-16.22, P=0.038). Conclusions We found an association between BW and SCD in the young, with an increased risk among SGA infants. In addition, we found an association between SGA and sudden arrhythmic death syndrome.

Sudden cardiac death among persons with diabetes aged 1-49 years: a 10-year nationwide study of 14 294 deaths in Denmark

AIMS

The aim of this study was to compare nationwide incidence rate (IR) of sudden cardiac death (SCD) in persons aged 1-49 years with and without diabetes mellitus (DM).

METHODS AND RESULTS

The study population consisted of all persons in Denmark aged 1-49 years in 2000-09, which equals 27.1 million person-years. All 14 294 deaths in the 10-year period were included. By using the highly descriptive Danish death certificates, 1698 cases of sudden and unexpected death were identified. Through review of autopsy reports, discharge summaries, and the Danish registries, we identified 1363 cases of SCD. The Danish Register of Medicinal Product Statistics was used to identify persons with type 1 DM and type 2 DM. Among the 14 294 decedents, there were 669 with DM, of which 118 suffered SCD (9% of all SCD), making SCD the leading cause of death among young persons with DM. Among those aged 1-35 years, the IR of SCD-DM was 21.9 per 100 000 person-years compared to 2.6 per 100 000 person-years among persons without DM [IR ratio 8.6, 95% confidence interval (CI) 5.8-28.6]. Within the age range 36-49 years, the IR among persons with DM was 119.8 per 100 000 person-years compared to 19.7 per 100 000 person-years among persons without DM (IR ratio 6.1, 95% CI 4.7-7.8).

CONCLUSION

We found that young persons with DM aged 1-35 years had >8-fold higher SCD IR compared to young persons without DM. Our study highlights the need for early cardiovascular risk monitoring and assessment in young persons with DM.

Diagnostic yield and long-term outcome of nonischemic sudden cardiac arrest survivors and their relatives: Results from a tertiary referral center

BACKGROUND

Cardiac arrest may be the first manifestation of most inherited cardiac diseases. International guidelines recommend screening of relatives of sudden cardiac arrest (SCA) survivors if an inherited cardiac disorder is suspected.

OBJECTIVE

The purpose of this study was to assess the prevalence and spectrum of inherited cardiac diseases and the long-term outcome in a consecutive cohort of nonischemic SCA survivors (probands) and their relatives.

METHODS

This retrospective study consecutively included probands and their relatives referred to our tertiary center for family screening between 2005 and 2018. All participants underwent a systematic workup and follow-up protocol. Data were retrieved from medical records.

RESULTS

We included 155 probands (age 41.2 ± 15.5 years; 61% male) and 282 relatives (age 35.7 ± 18.8 years; 51% male). Mean follow-up was 7.1 years for probands and 4.4 years for relatives. We identified an inherited cardiac disease in 76 (49%) probands and 42 (15%) relatives. An implantable cardioverter-defibrillator was inserted in 147 (95%) probands and 9 (3%) relatives. During follow-up, 4 (3%) probands and 3 (1%) relatives died, and 37 probands and 2 relatives received appropriate shock therapy. All relatives received genetic counseling, and 18 (6%) relatives started pharmacologic treatment during follow-up.

CONCLUSION

Systematic workup of nonischemic SCA survivors and their relatives identified an inherited cardiac disease in 49% of referred probands and 15% of their relatives. The favorable long-term prognosis of diagnosed relatives probably not only reflects lower age but also the effects of early diagnosis, treatment, and follow-up. These findings support systematic workup of SCA survivors and their relatives.

Non-diagnostic autopsy findings in sudden unexplained death victims

BACKGROUND

Several inherited cardiac diseases may lead to sudden cardiac death (SCD) a devastating event in the families. It is crucial to establish a post mortem diagnosis to facilitate relevant work-up and treatment of family members. Sudden unexplained death (SUD) victims constitute roughly one third of all SCD cases in Denmark.

METHODS

This was a single center, retrospective study investigating SUD cases. Victims who died unexplained due to suspected or confirmed cardiac disease were consecutively referred to a third line referral center established in 2005. All autopsy reports were investigated. Victims were divided into two groups: non-diagnostic cardiac findings and normal cardiac findings. None of the included victims had findings consistent with a diagnosis based on existing criteria.

RESULTS

In total, 99 SUD cases were referred. The mean age of the victims was 37 years (range 0-62 years, 75% males). A total of 14 (14%) victims had a cardiovascular diagnosis pre-mortem. Thirty-seven cases had normal cardiac findings and non-diagnostic cardiac findings were found in 62 cases (63%). The five most common findings included ventricular hypertrophy and/or enlarged heart (n = 35, 35%), coronary atheromatosis (n = 31, 31%), myocardial fibrosis (n = 19, 19%), dilated chambers (n = 7, 7%) and myocardial inflammation (n = 5, 5%).

CONCLUSION

One third of SUD victims had normal cardiac findings and non-diagnostic cardiac findings were seen in almost two thirds of the SUD victims. These non-diagnostic findings may be precursors or early markers for underlying structural cardiac disorders or may be innocent bystanders in some cases. Further studies and improved post-mortem examination methods are needed for optimization of diagnostics in SUD.

Symptoms and healthcare contact preceding sudden cardiac death in persons aged 1-49 years

Sudden Cardiac Death (SCD) is a leading cause of death among persons in their youth and early middle-age. To prevent SCD it is crucial to identify persons at high-risk of SCD. Knowledge of symptoms and medical contact prior to SCD could potentially aid in the identification of high-risk persons in the general population who would benefit from further investigation. This review aims to summarize the current knowledge of symptoms and healthcare contact preceding SCD in persons aged 1-49 years, and to explore how the symptoms differ according to SCD cause and age of the deceased. There was a high frequency of both cardiac and non-specific symptoms prior to SCD. Additionally, many SCD victims contacted the healthcare system prior to death on the basis of their symptoms and only a few were diagnosed with cardiovascular disease. This information underlines that young persons reporting potential cardiac symptoms should also be thoroughly examined. Furthermore, such symptoms could be used in combination with other easily accessible information in non-invasive prediction models aiming at identifying persons at high risk of SCD that would benefit from further investigation and possibly treatment.

Editorial commentary: When should the patient with an inherited cardiac disease have an ICD?

The implantable cardioverter defibrillator (ICD) is often considered a routine intervention for an inherited heart rhythm disorder (IHRD) despite there being little to no randomized data for non-ischemic indications. Furthermore, existing IHRD studies often do not report adverse ICD outcomes, and observational data increasingly show that complications are under-recognized. Only recently have tools emerged to address the rational use of ICDs for specific forms of IHRD, although the acceptable risk of device complications remains unestablished. Here, we summarize the evidence of ICD benefit and harm in IHRD, highlight current knowledge gaps, and propose alternative and adjunctive options to the transvenous ICD.

P2821Diagnostic yield and outcomes of systematic work-up of aborted sudden cardiac death victims and their relatives

Introduction

Cardiac arrest can be the first manifestation of most inherited cardiac diseases. This motivates the international guidelines recommending screening of relatives of cardiac arrest survivors (aSCD) if an inherited cardiac disorder might have caused the cardiac arrest.

Purpose

To assess the presence of inheritable cardiac diseases in cardiac arrest survivors and their relatives.

Methods

In this retrospective study we consecutively included cardiac arrest survivors (probands) and their relatives referred to our tertiary referral center from 2005 to 2018. All probands and relatives underwent a systematic screening protocol. Data were retrieved from medical files. Only probands with non-ischemic heart disease were included.

Results

We included 155 probands (41±16 years old, 94 (61%) male) and 284 relatives (36±19 years old, 144 (51%) male). We identified an inheritable cardiac disease in 70 (45%) probands, most frequently cardiomyopathies (41, 26%) followed by channelopathies (27, 17%) (figure). A borderline diagnosis was found in 32 (21%) probands. In the relatives, an inheritable diagnosis was identified in 38 (13%) individuals, most frequently channelopathies (23, 8%), and a borderline diagnosis was identified in 33 (12%) individuals.

Conclusion

Clinical assessment of aSCD cases on a non-ischemic basis identified an inheritable cardiac disease as the most likely etiology in almost half of the probands and in 13% of the relatives.

P2830Clinical and genetic findings in relatives to young sudden cardiac death victims without post-mortem examination (autopsy)

Background

Guidelines recommend clinical assessment of relatives to young sudden cardiac death (SCD) victims (<50 years) to protect the surviving relatives by pre-symptomatic interventions, in case the SCD was due to an inherited cardiac disorder. The etiology is an inherited cardiac disease in about 50% of young SCD cases. The work-up of relatives is generally guided by findings in the SCD victim. If post-mortem examinations (autopsies) have not been performed the work-up of relatives is challenged. The diagnostic hit-ratio of screening of relatives under these circumstances is unclear.

Purpose

To assess the diagnostic yield of inherited cardiac diseases of cardiac work-up in relatives of SCD victims, where no autopsy had been performed.

Methods

This retrospective study consecutively included families referred to our tertiary referral centre, specialised in hereditary cardiac diseases, during the period 2005 to 2018 due to SCD in the family. No autopsy had been performed in any of the SCD victims. The relatives underwent standard cardiac work-up according to guidelines. Based on the findings in the relatives the families were categorised into: 1) definite diagnosis, 2) borderline diagnosis or 3) undiagnosed.

Results

We assessed 149 relatives (43±16 age, 48% men) to 84 SCD un-autopsied cases (44±11 age, 79% men). In 11 (13%) families a definite diagnosis was established, in 8 (10%) families a borderline diagnosis was found and the remaining 65 (77%) families remained undiagnosed. The most common diagnosis was premature IHD (36%) followed by cardiomyopathies (27%) and channelopathies (27%). A disease-causing mutation was identified in 3 families out of 15 genetically examined families.

Conclusion

Systematic cardiac work-up of relatives to not-autopsied SCD victims, revealed a definite hereditary cardiac disease in 13% of the referred families, and a borderline diagnosis in additionally 10% of the families. Despite a reduced diagnostic yield in family members of non-autopsied SCD victims, work-up of relatives is clearly still justified.

Sudden cardiac death caused by myocarditis in persons aged 1-49 years: a nationwide study of 14 294 deaths in Denmark

Myocarditis is associated with an increased risk of sudden cardiac death (SCD) in the young. However, information on nationwide burden of SCD caused by myocarditis (SCD-myocarditis) is sparse. For this study all deaths among persons in Denmark aged 1–35 years in 2000–2009 and 36–49 years in 2007–2009 (27.1 million person-years) were included. Autopsy reports, death certificates, discharge summaries, and nationwide registries were used to identify all cases of SCD-myocarditis. In the 10-year study period, there were 14 294 deaths, of which we identified 1 363 (10%) SCD. Among autopsied SCD (n = 753, 55%), cause of death was myocarditis in 42 (6%) cases corresponding to an SCD-myocarditis incidence of 0.16 (95%CI: 0.11–0.21) per 100 000 person-years. Males had significantly higher incidence rates of SCD-myocarditis compared to females with an incidence rate ratio of 2.2 (95%CI: 1.1–4.1). Myocarditis was not registered as cause of death in any of the non-autopsied SCD (n = 610, 45%). In conclusion, after nationwide unselected inclusion of 14 294 deaths, we found that 6% of all autopsied SCD was caused by myocarditis. No cases of SCD-myocarditis were reported in the non-autopsied SCD, which could reflect underdiagnosing of myocarditis in non-autopsied SCD. Furthermore, our data suggest a female protection towards SCD-myocarditis.

Nationwide Study of Sudden Cardiac Death in People With Congenital Heart Defects Aged 0 to 35 Years

BACKGROUND

Congenital heart defects (CHD) are among the leading causes of sudden cardiac death (SCD) in the young. Nationwide incidence of SCD in people with CHD (SCD-CHD) has not been established in the young general population. The aims of this study were to investigate incidence of SCD-CHD and whether incidence of SCD-CHD in infants declined after implementation of nationwide fetal ultrasound screening in Denmark.

METHODS

All deaths (n=11 451) among people aged 0 to 35 years in Denmark in 2000 to 2009 (24.4 million person-years) were included. Danish death certificates, autopsy reports, records from hospitals and general practitioners, and data from nationwide Danish registries were used to identify SCD-CHD cases.

RESULTS

We identified 90 (11%) cases of SCD-CHD from 809 SCD. The incidence rate of SCD-CHD was 0.4 per 100 000 person-years among people aged 0 to 35 years. In total, 53 (59%) were diagnosed with CHD before death. Incidence of SCD was 9.6× higher among patients with CHD compared with people without CHD (P<0.01). Annual incidence of physical activity-related SCD-CHD among patients aged 2 to 35 years diagnosed with CHD was 0.9 per 100 000. The annual incidence rate of SCD-CHD in infants declined after implementation of nationwide fetal ultrasound screening (incidence rate ratio, 3.8; P<0.01).

CONCLUSIONS

The proportion of SCD-CHD in the young was 11%, which is higher than previously reported. Physical activity-related SCD-CHD was a rare event among patients with CHD. We observed an ≈4-fold lower incidence of SCD-CHD among infants born after implementation of nationwide screening.