Causes, circumstances, and potential preventability of cardiac arrest in the young: insights from a state-wide clinical and forensic registry

Drug-induced cardiac arrest: a pharmacovigilance study from 2004-2024 based on FAERS database

Objective

Utilizing the FDA Adverse Event Reporting System (FAERS) database, this study conducts signal detection for drugs associated with cardiac arrest (CA), aiming to optimize clinical decision-making and ensure safer drug usage.

Methods

Adverse event reports related to CA from the first quarter of 2004 to the second quarter of 2024 were extracted from the FAERS database. Signal detection was conducted using the reporting odds ratio (ROR) and proportional reporting ratio (PRR) to identify drugs associated with an increased risk of CA.

Results

A total of 66,431 reports were analyzed, comprising 34,508 males (51.9%) and 31,923 females (48.1%). The majority of cases (71.8%) were reported by healthcare professionals, with adults (≥18 years old) representing the predominant group. Clinical outcomes showed that 67.2% of cases resulted in death. Out of 82 drugs with over 100 CA-related reports, 43 displayed positive signals. The top five drugs identified by ROR were: carisoprodol [ROR (95% CI): 34.13 (29.62-39.32)], sugammadex [ROR (95% CI): 26.93 (22.56-32.16)], regadenoson [ROR (95% CI): 20.00 (17.69-22.60)], alprazolam [ROR (95% CI): 12.82 (12.19-13.48)], and propofol [ROR (95% CI): 11.93 (10.61-13.41)]. In the system drug signal detection, musculo-skeletal system drugs ranked highest [ROR (95% CI): 30.99 (27.74-34.62)], followed by alimentary tract and metabolism drugs [ROR (95% CI): 4.75 (4.59-4.92)], nervous system drugs [ROR (95% CI): 4.51 (4.4-4.61)], anti-infective drugs [ROR (95% CI): 4.13 (3.74-4.57)], cardiovascular drugs [ROR (95% CI): 3.89 (3.78-4.01)], and antineoplastic and immunomodulating agents [ROR (95% CI): 2.16 (2.13-2.2)].

Conclusion

This study identifies over 40 drugs potentially associated with an elevated risk of CA based on FAERS data. Healthcare professionals should be particularly vigilant when prescribing these drugs, especially to patients with a history of heart disease, and ensure rigorous monitoring of their cardiac health.

Pathological contributors to organ damage and mortality in systemic sclerosis: a nationwide matched case-control study

BACKGROUND

Mortality is increased in systemic sclerosis (SSc), including a 10-15-fold increase in sudden cardiac death. Limited histopathology data exist to understand the pathogenesis of this excess. This study aimed to compare heart, lung and renal histopathology at autopsy between SSc and controls.

METHODS

A matched case-control study was performed using autopsy data from the Australian National Coronial Information System. SSc cases were selected via keyword search, and age- and sex-matched to controls identified from motor vehicle accidents. Cause of death, antemortem comorbidities and autopsy findings were extracted. Odds ratios were calculated with 95 % confidence intervals (CI).

FINDINGS

Fifty-nine SSc cases (64 years, 81 % female) were matched to 59 controls (62 years, 81 % female). Myocardial fibrosis was 11-times more common in SSc (95 %CI 4-29, p < 0.01), inflammation 39-times more common (95 %CI 2-672, p = 0.01) and small vessel vasculopathy 27-times more common (95 %CI 2-485, p = 0.02), despite no difference in epicardial coronary artery disease (p = 0.24). Two-thirds of SSc cases had myocardial fibrosis with no identifiable secondary cause (e.g., coronary/valvular lesions). Pulmonary fibrosis, inflammation and vasculopathy ranged from 23 to 100-times more common in SSc. Renal fibrosis/scarring, inflammation/infiltrates and vasculopathy were 3-6-times more common in SSc. Among SSc cases, combined pathologies (≥2 of fibrosis, inflammation or vasculopathy) were seen concurrently in 31 % of hearts, 41 % of lungs and 45 % of kidneys.

INTERPRETATION

The high frequency of unexplained myocardial fibrosis in SSc provides insights into the mechanism of excess mortality and sudden cardiac death observed in SSc. This matched autopsy study demonstrates the mechanisms and complexity of organ damage in SSc, with 30-45 % of organs displaying multiple concurrent pathologies.

From rare events to systematic data collection: the RESCUED registry for sudden cardiac death in the young in Germany

BACKGROUND

Approximately one-third of sudden cardiac deaths in the young (SCDY) occur due to a structural cardiac disease. Forty to fifty percent of SCDY cases remain unexplained after autopsy (including microscopic and forensic-toxicological analyses), suggesting arrhythmia syndromes as a possible cause of death. Due to the possible inheritability of these diseases, blood relatives of the deceased may equally be carriers of the causative genetic variations and therefore may have an increased cardiac risk profile. A better understanding of the forensic, clinical, and genetic data might help identify a subset of the general population that is at increased risk of sudden cardiac death.

STUDY DESIGN

The German registry RESCUED (REgistry for Sudden Cardiac and UnExpected Death) comprises information about SCDY fatalities and clinical and genetic data of both the deceased and their biological relatives. The datasets collected in the RESCUED registry will allow for the identification of leading causes of SCDY in Germany and offer unique possibilities of scientific analyses with the aim of detecting unrecognized trends, risk factors, and clinical warning signs of SCDY. In a pilot phase of 24 months, approximately 180 SCDY cases (< 50 years of age) and 500 family members and clinical patients will be included.

CONCLUSION

RESCUED is the first registry in Germany collecting comprehensive data of SCDY cases and clinical data of the biological relatives reviewed by cardiac experts. RESCUED aims to improve individual risk assessment and public health approaches by directing resources towards early diagnosis and evidence-based, personalized therapy and prevention in affected families. Trial registration number (TRN): DRKS00033543.

Adrenal aldosterone synthase (CYP11B2) histopathology and its association with disease-induced sudden death: a cross-sectional study

Background

Unidentified cardiovascular risk factors may account for approximately half of sudden deaths, a devastating event with limited preventive tools. We investigated whether adrenal histopathology suggestive of primary aldosteronism, pheochromocytoma, or adrenal masses could explain part of the risk for disease-induced sudden death (DSD).

Methods

In this study, autopsies and histopathological analyses, including aldosterone synthase staining of adrenal glands, were performed on 403 consecutive individuals who experienced sudden death. These individuals were classified into 258 cases of DSD and 144 deaths caused by trauma, suicide, or intoxication, i.e., non-disease-induced sudden death (nDSD). This trial was registered at ClinicalTrials.gov (NCT05446779).

Findings

Adrenal histopathology revealed changes in 31 (7.7%) subjects of the cohort. Of these, the most prevalent findings [25 (6.2%)] were aldosterone-producing adenomas (APA) or nodules (APN), which were associated with myocardial infarction and atherosclerosis at autopsy. Individuals in the DSD group and the subgroup with sudden cardiac death (SCD) were more likely to have APA or APN than individuals in the nDSD group [23 (8.9%) vs. 2 (1.4%), p = 0.002; 16 (8.8%) vs. 2 (1.4%), p = 0.003, respectively]. APA or APN were explanatory factors for DSD (odds ratio [OR] 6.47, 95% confidence interval [CI] 1.40-29.88, p = 0.017) and SCD (OR 10.68, 95% CI 2.02-56.43, p = 0.005). Other findings included two pheochromocytomas, one bilateral adrenal metastasis, and two unilateral adrenal metastases.

Interpretation

In this exploratory study, APA or APN were more frequently seen in DSD and SCD than nDSD cases. Whether primary aldosteronism constitutes a novel risk factor for sudden death warrants further study.

Funding

Finnish State Research funds and independent research foundations: Aarne Koskelo Foundation, the Finnish Kidney Foundation, and the Finnish Foundation for Cardiovascular Research.

Proteinuria Is Associated With an Increased Risk of Sudden Cardiac Arrest in the Young Population

BACKGROUND

Proteinuria is a risk factor for cardiovascular events, but its prognostic value for sudden cardiac arrest (SCA) in young individuals remains unproven. We aimed to evaluate whether proteinuria in young people is associated with an increased risk of SCA.

METHODS AND RESULTS

Individuals aged between 20 and 39 years who underwent health screening between 2009 and 2012 in South Korea were included (n=6 891 400). Urine protein was measured using the spot urine dipstick method. Main outcome was SCA identified by International Classification of Diseases, Tenth Revision (ICD-10). Participants included in the analysis were followed-up till December 2020, and Cox proportional hazards model was used to demonstrate the risk of SCA. The mean age was 30.9±5.0 years, and 3 775 535 (59.5%) were men. The mean follow-up duration was 9.4±1.2 years. During follow-up, SCA occurred in 5352 individuals (0.08%). Participants with proteinuria had a higher incidence of SCA (n=182, incidence rate 0.19, during 962 956 person-year follow-up) than those without proteinuria (n=5170, incidence rate 0.09, during 58 465 181 person-year follow-up). Adjustment of confounders resulted higher risk of SCA in participants with proteinuria (adjusted hazard ratio 1.71 [95% CI=1.47-1.99], P<0.001). Participants with proteinuria +3-4 showed a significant increase in the risk of SCA (2.94 [1.96-4.40], P<0.001). The influence of proteinuria on SCA was stronger in advanced chronic kidney disease (stage 3 and stage 4-5).

CONCLUSIONS

Proteinuria was significantly associated with an increased risk of SCA in young people. Individuals with pre-existing chronic kidney disease showed a stronger association between proteinuria and the risk of SCA.

Out-of-Hospital Cardiac Arrest in Apparently Healthy, Young Adults

Importance

Out-of-hospital cardiac arrest incidence in apparently healthy adults younger than 40 years ranges from 4 to 14 per 100 000 person-years worldwide. Of an estimated 350 000 to 450 000 total annual out-of-hospital cardiac arrests in the US, approximately 10% survive.

Observations

Among young adults who have had cardiac arrest outside of a hospital, approximately 60% die before reaching a hospital (presumed sudden cardiac death), approximately 40% survive to hospitalization (resuscitated sudden cardiac arrest), and 9% to 16% survive to hospital discharge (sudden cardiac arrest survivor), of whom approximately 90% have a good neurological status (Cerebral Performance Category 1 or 2). Autopsy-based studies demonstrate that 55% to 69% of young adults with presumed sudden cardiac death have underlying cardiac causes, including sudden arrhythmic death syndrome (normal heart by autopsy, most common in athletes) and structural heart disease such as coronary artery disease. Among young adults, noncardiac causes of cardiac arrest outside of a hospital may include drug overdose, pulmonary embolism, subarachnoid hemorrhage, seizure, anaphylaxis, and infection. More than half of young adults with presumed sudden cardiac death had identifiable cardiovascular risk factors such as hypertension and diabetes. Genetic cardiac disease such as long QT syndrome or dilated cardiomyopathy may be found in 2% to 22% of young adult survivors of cardiac arrest outside of the hospital, which is a lower yield than for nonsurvivors (13%-34%) with autopsy-confirmed sudden cardiac death. Persons resuscitated from sudden cardiac arrest should undergo evaluation with a basic metabolic profile and serum troponin; urine toxicology test; electrocardiogram; chest x-ray; head-to-pelvis computed tomography; and bedside ultrasound to assess for pericardial tamponade, aortic dissection, or hemorrhage. Underlying reversible causes, such as ST elevation myocardial infarction, coronary anomaly, and illicit drug or medication overdose (including QT-prolonging medicines) should be treated. If an initial evaluation does not reveal the cause of an out-of-hospital cardiac arrest, transthoracic echocardiography should be performed to screen for structural heart disease (eg, unsuspected cardiomyopathy) or valvular disease (eg, mitral valve prolapse) that can precipitate sudden cardiac death. Defibrillator implant is indicated for young adult sudden cardiac arrest survivors with nonreversible cardiac causes including structural heart disease and arrhythmia syndromes.

Conclusions and Relevance

Cardiac arrest in apparently healthy adults younger than 40 years may be due to inherited or acquired cardiac disease or noncardiac causes. Among young adults who have had cardiac arrest outside of a hospital, only 9% to 16% survive to hospital discharge. Sudden cardiac arrest survivors require comprehensive evaluation for underlying causes of cardiac arrest and cardiac defibrillator should be implanted in those with nonreversible cardiac causes of out-of-hospital cardiac arrest.

Cardiac arrest in Australia: a call to action

Sudden cardiac arrest (SCA) represents a major cause of premature mortality globally, with an enormous effect on victims, families, and communities. Cardiac arrest prevention should be considered a health priority in Australia. A multi-faceted strategy will include community awareness, improved fundamental mechanistic understanding, preventive strategies, implementation of best-practice resuscitation strategies, secondary risk assessment of family members, and development of (near) real-time registries to inform areas of need and assess the effectiveness of interventions. Challenges of patient access to specialised care and equity within the Australian and New Zealand healthcare system should also be recognised.

Declining Trend of Sudden Cardiac Death in Younger Individuals: A 20-Year Nationwide Study

BACKGROUND

Declining cardiovascular mortality rates have been well-documented, yet temporal trends of sudden cardiac death (SCD) in young individuals remain unclear. We provide contemporary nationwide estimates of the temporal trends of SCD in young individuals (1-35 years of age) from 2000 through 2019 and correlate these trends to changes in out-of-hospital cardiac arrest (OHCA) patterns, rates of inherited cardiac diseases, and implantations of implantable cardioverter defibrillators (ICD).

METHODS

All individuals between 1 and 35 years of age living in Denmark from 2000 through 2019 were included, with annual re-evaluation of the at-risk population in regard to age. Adjudication of SCD cases relied on multiple sources, including death certificates, medical files, and autopsy reports. Information on OHCA, diagnostic rates, and ICD implantations were captured from nationwide administrative registries. Annual incidence rates of SCD were calculated, and temporal trends in SCD incidence were computed as percentage change annualized. Trends in OHCA survival and characteristics, diagnostic rates of inherited cardiac diseases, and ICD implantations were assessed.

RESULTS

During the 20-year study period (47.5 million person-years), 1057 SCDs were identified (median age, 29 years; 69% male). The overall incidence of SCD was 2.2 per 100 000 person-years and declined by 3.31% (95% CI, 2.42-4.20) annually, corresponding to a 49% (95% CI, 38.7-57.6) reduction during the study. Rates of witnessed SCD declined markedly (percentage change annualized -7.03% [95% CI, -8.57 to -5.48]), but we observed no changes in the rate of unwitnessed SCD (percentage change annualized -0.09% [95% CI, -1.48 to 1.31]). Therefore, the proportion of unwitnessed SCD increased by 79% (P<0.001). Survival after OHCA in young individuals (1 to 35 years of age) increased from 3.9% to 28%, mainly because of increased bystander cardiopulmonary resuscitation and defibrillation rates. Diagnostic rates of inherited cardiac diseases increased 10-fold (incidence rate ratio, 10.4 [95% CI, 8.46-12.90]) and the ICD implantation rate increased 2-fold (incidence rate ratio, 1.97 [95% CI, 1.51-2.60]).

CONCLUSIONS

SCD incidence rates in young individuals declined by 49% over the past 2 decades. The decline was paralleled by improved survival of OHCA, higher diagnostic rates of inherited cardiac diseases, and higher ICD implantation rates. However, rates of unwitnessed SCD were unchanged, which calls for new perspectives in preventive strategies.

Early Coronary Angiography in Patients With Out-of-Hospital Cardiac Arrest Without ST-Segment Elevation: A Systematic Review, Meta-Analysis, and Comparative Analysis of Studies

Out-of-hospital cardiac arrest has a high mortality rate. Unlike ST-elevation myocardial infarction, the results of performing early coronary angiography (CAG) in non-ST-elevation myocardial infarction patients are controversial. This study aimed to compare early and nonearly CAG in this population, in addition to the identification of differences between randomized controlled trials (RCTs) and observational studies conducted in this regard. A systematic search in PubMed, Embase, and Cochrane library was performed to identify the relevant studies. Random-effect meta-analysis was done to calculate the pooled effect size of early versus nonearly CAG outcomes in all studies in addition to each of the RCT and observational subgroups of the studies. The relative risk ratio (RR), along with its 95% confidence interval (CI), was used as a measure of difference. A total of 16 studies including 5234 cases were included in our analyses. Compared with observational cohorts, RCT studies had patients with higher baseline comorbidities (older age, hypertension, diabetes, and coronary artery disease). Random-effect analysis revealed a lower rate of in-hospital mortality in the early-CAG group (RR, 0.79; 95% CI, 0.65-0.97; P = 0.02); however, RCT studies did not find a statistical difference in this outcome (RR, 1.01; 95% CI, 0.83-1.23; P = 0.91). Moreover, mid-term mortality rates were lower in the early-CAG group (RR, 0.87; 95% CI, 0.78-0.98; P = 0.02), mostly due to observational studies. There was no significant difference between the groups in other efficacy and safety outcomes. Although early CAG was associated with lower in-hospital and mid-term mortality in overall analyses, no such difference was confirmed by the results obtained from RCTs. Current evidence from RCTs may not be representative of real-world patients and should be interpreted within its limitation.

A Call to Action to Improve Cardiac Arrest Outcomes: A Report From the National Summit for Cardiac Arrest

Sudden cardiac arrest (SCA) represents a major cause of premature mortality globally, with enormous impact and financial cost to victims, families, and communities. SCA prevention should be considered a health priority in Australia. National Cardiac Arrest Summits were held in June 2022 and March 2023, with inclusion from multi-faceted endeavours related to SCA prevention. It was agreed to establish a multidisciplinary Australian Sudden Cardiac Arrest Alliance (AuSCAA) working group charged with developing a national unified strategy, with clear and measurable quality indicators and standardised outcome measures, to amplify the goal of SCA prevention throughout Australia. A multi-faceted prevention strategy will include i) endeavours to progress community awareness, ii) improved fundamental mechanistic understanding, iii) implementation of best-practice resuscitation strategies for all demographics and locations, iv) secondary risk assessment directed to family members, and v) development of (near) real-time registry of cardiac arrest cases to inform areas of need and effectiveness of interventions. Together, we can and should reduce the impact of SCA in Australia.

Navigating Coronary Artery Disease in Aviation Cardiology in Australia and New Zealand

BACKGROUND

Cardiologists will commonly assess patients who hold an aviation medical certificate and require unique assessments and communications with national civil aviation authorities (in Australia, the Civil Aviation Safety Authority [CASA] and in New Zealand, the Civil Aviation Authority of New Zealand [CAA NZ]). Cardiac conditions are the most common reason for disqualification from holding an aviation licence, and coronary artery disease is considered a high-risk condition for pilot incapacitation.

AIM

To provide a contemporary update on the aeromedical approach to the evaluation, detection, and management of coronary artery disease in an Australasian context.

METHODS

A narrative view of current and historical practice in the area of aeromedical evaluation of coronary disease was undertaken.

RESULTS

This review highlights the aeromedical approach to risk stratification and specific challenges of the aviation environment for patients with coronary artery disease. Scenarios of coronary artery disease screening, common and rare acute coronary syndromes, and the assessment of established coronary artery disease are examined in detail. Suggestions to facilitate communications between specialists and CASA or CAA NZ to facilitate patient re-certification are also provided.

CONCLUSION

Patients who are pilots have unique requirements in terms of their coronary assessment, management, and follow-up to maintain eligibility to fly. It is important for cardiologists to be aware of relevant occupational requirements to provide optimal care to their patients.

Atrial fibrillation and risk of sudden cardiac arrest in young adults

AIMS

Evidence of an association between atrial fibrillation (AF) and sudden cardiac arrest (SCA) in young adults is limited. In this study, we aim to evaluate this association in a general population aged between 20 and 39 years.

METHODS AND RESULTS

Young adults who underwent health check-ups between 2009 and 2012 were screened from a nationwide healthcare database in South Korea. A history of AF diagnosis before the health check-ups was identified based on the relevant International Classification of Diseases, 10th edition codes reported in the database. Associations between an established diagnosis of AF and the risk of SCA during follow-up were examined. A total of 6 345 162 young people were analysed with a mean follow-up duration of 9.4 years. The mean age was 30.9 ± 5.0 years, and 5875 (0.09%) individuals were diagnosed with AF. During follow-up, SCA occurred in 5352 (0.08%) individuals, and the crude incidence was 0.56 and 0.09 events per 1000 person-years for participants with and without AF, respectively. Individuals with AF had a 3.0-fold higher risk in a multivariate model adjusted for age, sex, lifestyle, anthropometric data, and medical comorbidities (adjusted hazard ratio 2.96, 95% confidence interval 1.99-4.41, P < 0.001). Both incident and prevalent AFs were associated with an increased risk of SCA, with no significant differences between the two groups.

CONCLUSION

Atrial fibrillation was associated with a significantly higher risk of SCA developing in healthy young adults. Whether the rate or rhythm control influences the risk of SCA in young patients with AF remains to be examined.

Prevalence of atrial septal defects and patent foramen ovale in a cohort of sudden cardiac death patients undergoing autopsy

BACKGROUND

Patent foramen ovale (PFO) and atrial septal defects (ASD) have been described in up to 30 % of subjects in autopsy series but contemporary data are scarce. It is important to confirm the prevalence of ASD/PFO in the general population given the potential associated stroke risk and the increasing availability of intervention via PFO closure.

METHODS

A state-wide prospective out-of-hospital cardiac arrest registry (OHCA) identified all patients aged 1 to 50 years who experienced OHCA in Victoria, Australia from April 2019 to April 2022 and subsequently underwent autopsy with a cardiac cause of death identified. Autopsy was performed including visual description of any ASD and identification of probe patency of foramen ovale.

RESULTS

A total of 517 patients underwent autopsy in the setting of sudden cardiac death; 36 patients (6.9 %) had a probe-patent foramen ovale, 2 patients (0.4 %) had secundum ASD, and 2 patients (0.4 %) had both a PFO and ASD (1 of whom had undergone percutaneous repair of both lesions). Twelve patients (2.3 %) had a prior history of cerebrovascular accident either recorded on medical history or detected on neuropathological examination; however none of these patients had a PFO or ASD.

CONCLUSIONS

The combined rate of PFO and ASD in a cohort of 517 patients undergoing autopsy was 7.9 %. None of these patients had experienced a cerebrovascular accident. This rate of PFOs appears lower than earlier reports and raises the possibility that the relative risk of an associated stroke could be higher than previously estimated.

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.

Toxicology Screening in Sports-Related Sudden Cardiac Death: A Multinational Observational Study

BACKGROUND

Knowledge of toxicological findings among sports-related sudden cardiac death (SrSCD) is scarce.

OBJECTIVES

This study aimed to describe postmortem toxicology findings in a multinational cohort of young SrSCD.

METHODS

Patients with sudden cardiac death (SCD) aged 12 to 49 years with a complete post mortem were included from Denmark, Spain, and Australia. Postmortem findings were compared between SrSCD and non-SrSCD, and toxicology findings in SrSCD were assessed.

RESULTS

We included 3,189 SCD, of which 219 (7%) were sports-related. SrSCD patients were younger (36 years vs 41 years; P < 0.001) and of male predominance (96% vs 75%; P < 0.001), and their death was more often caused by structural cardiac disease (68% vs 61%; P = 0.038). Positive toxicology screenings were significantly less likely among SrSCD than non-SrSCD (12% vs 43%; P < 0.001), corresponding to 82% lower odds of a positive toxicology screening in SrSCD. Patient characteristics were similar between SrSCDs with positive and negative toxicology screenings, but deaths were more often unexplained (59% vs 34%). Nonopioid analgesics were the most common finding (3%), and SCD-associated drugs were detected in 6% of SrSCD. SUD was more prevalent among the SrSCD with positive toxicology (59% vs 34%).

CONCLUSIONS

Sports-related SCD mainly occurred in younger men with structural heart disease. They had a significantly lower prevalence of a positive toxicology screening compared with non-SrSCD, and detection of SCD-associated drugs was rare.

Association between accelerometer-derived physical activity and incident cardiac arrest

AIMS

Studies on objectively measured physical activity (PA) have investigated acute cardiovascular outcomes but not cardiac arrest (CA). Our study aimed to investigate the dose-response relationship between accelerometer-measured PA and CA by intensity of PA.

METHODS AND RESULTS

This prospective cohort study included 98 893 UK Biobank participants whose PA data were measured using wrist-worn accelerometers. Total PA volume was measured using the average overall acceleration. Minutes per week of light PA (LPA), moderate PA (MPA), and vigorous PA (VPA) were recorded. The incident CA was identified using diagnostic codes linked to hospital encounters and death records. Cox proportional hazard models with restricted cubic splines were used to study the associations, including sex differences. During the follow-up period (median: 7.31 years; interquartile range: 6.78-7.82 years), 282 incident CAs (0.39 per 1000 person-years) occurred. Total PA was inversely related to CA risk. The CA risk decreased sharply until the time spent in MPA or VPA reached ∼360 min or 20 min per week, respectively, after which it was relatively flat. The LPA was not associated with CA risk. Subgroup analyses showed a more pronounced association between PA and a reduced risk of CA in women compared to men.

CONCLUSION

Accelerometer-measured PA, particularly MPA and VPA, was associated with a lower CA risk. Furthermore, a stronger association was observed in women than men.

Prevalence of Multiple Causes of Death Within Young and Middle-Aged People Experiencing Sudden Cardiac Arrest

BACKGROUND

Multiple causes of death are increasingly reported, particularly in older populations. Rates of multiple causes of young sudden death have not been quantified.

METHOD

The End Unexplained Cardiac Death (EndUCD) registry was utilised to identify cases of young sudden death (aged 1-50 years) referred for forensic assessment from April 2019 to April 2022. Causes of death were coded according to whether one or more underlying causes of death were identified. Patients were compared according to the number of causes of death, with significant predictors assessed using logistic regression analysis.

RESULTS

1,085 cases of sudden death were identified. 263 (24.2%) cases had more than one competing cause of their sudden death. The most common multi-causal associations identified were dual non-cardiac causes of the sudden death (n=68), cardiomyopathy with non-cardiac event (n=64) and coronary artery disease with non-cardiac cause (n=63). Multi-causal death was more common in those undergoing comprehensive autopsy examination (95.8% vs 77.6%, p<0.0001), and in the setting of higher body mass index (median 31.3 kg/m2 vs 29.9 kg/m2, p=0.01), older age (44.3 years vs 41.4 years, p<0.0001), non-ventricular cardiac arrest rhythm (93.2% vs 87.3%, p=0.009), and smoking (22.8% vs 14.2%, p=0.001). The strongest predictor of multiple pathologies was comprehensive autopsy examination compared with external inspection, full-body post-mortem computed tomography and review of ancillary documentation and investigations (odds ratio 6.49, 95% confidence interval 3.47-12.14).

CONCLUSIONS

One-quarter of young sudden deaths have more than one underlying cause, highlighting the value of comprehensive investigations including autopsy. Awareness of the complexity of young sudden death is important, along with multidisciplinary involvement to ensure all contributors to death are identified.

Future direction of substrate-based catheter ablation in Brugada syndrome and other inherited primary arrhythmia syndromes: Systematic review and meta-analysis

Background

Inherited Primary Arrhythmias Syndromes (IPAS), especially Brugada syndrome (BrS), have been associated with arrhythmogenic substrates that can be targeted through ablation. This meta-analysis evaluated the outcomes of catheter ablation (CA) in different types of IPAS based on procedural guidance and location.

Methods

A systematic search was conducted across multiple databases to identify studies reporting on ventricular arrhythmia (VA) events before and after CA in IPAS, including BrS, Long-QT syndrome (LQTS), Early repolarization syndrome (ERS), and Idiopathic ventricular fibrillation (IVF). The primary outcomes were VA recurrence and VA burden, evaluated through conditional subgroup analysis. Procedural data were collected as secondary outcomes.

Results

A total of 21 studies involving 584 IPAS patients who underwent CA were included. Following a mean follow-up duration of 33.5 months, substrate-based ablation demonstrated efficacy in reducing VA recurrence across all types of IPAS [RR 0.23; 95% CI (0.13-0.39); p < .001; I 2 = 74%]. However, activation guidance ablation was found to be effective only in IVF cases. Although recurrences still occurred, CA was successful in reducing VA burden [MD -4.70; 95% CI (-6.11-(-3.29); p < .001; I 2 = 74%]. The mean size of arrhythmogenic substrate was 15.70 cm2 [95% CI (12.34-19.99 cm2)], predominantly distributed in the epicardial right ventricular outflow tract (RVOT) in BrS cases and LQTS [Proportion 0.99; 95% CI (0.96-1.00) and Proportion 0.82; 95% CI ( 0.59-1.00), respectively].

Conclusion

Substrate-based CA has demonstrated effective prevention of VA and reduction in VA burden in IPAS cases.

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.

Prevalence of illicit drug use in young patients with sudden cardiac death

BACKGROUND

Illicit drug use may accelerate coronary disease and cardiac hypertrophy or stimulate arrhythmias. Rates of illicit drug use in young patients with sudden cardiac death (SCD) are uncertain.

OBJECTIVE

The purpose of this study was to identify rates of illicit drug use in young patients with SCD.

METHODS

A prospective statewide registry identified out-of-hospital patients with cardiac arrest aged 18-50 years from April 2019 to April 2021. Clinical characteristics were compared between patients with and without illicit drug use (defined by toxicological results or reported regular use). Illicit drugs included amphetamine-type substances, cocaine, heroin, cannabis, and other drugs.

RESULTS

A total of 554 (40.2%) of 1378 patients had confirmed cardiac cause of out-of-hospital cardiac arrest, with 523 undergoing toxicological assessment. There were 170 patients (32.5%) having either positive toxicology for illicit drugs (n = 138) or negative toxicology but reported regular drug use (n = 32). Patients with SCD and illicit drug use were more commonly male (81.2% vs 72.3%; P = .028), smokers (38.8% vs 19.8%; P ≤ .0001), and excess alcohol drinkers (30.6% vs 20.6%; P = .012) and had a psychiatric diagnosis (38.8% vs 25.7%; P = .002), lower body mass index (29.4 kg/m2 vs 31.7 kg/m2; P = .0063), and lower rates of hypertension (10.6% vs 18.6%; P = .019). Death commonly occurred while sedentary (47.5%) or during sleep (45.8%). Accounting for these baseline differences, there were no differences in rates of coronary disease or cardiomyopathy. Cannabis (n = 106) was the most common illicit drug identified and polysubstance abuse occurred frequently (n = 25).

CONCLUSION

Approximately one-third of young patients with SCD have positive toxicology at the time of death or reported frequent use of illicit drugs, with high rates of polysubstance abuse.

Triglyceride-glucose index is associated with the occurrence and prognosis of cardiac arrest: a multicenter retrospective observational study

BACKGROUND

Triglyceride-glucose (TyG) index is an efficient indicator of insulin resistance and is proven to be a valuable marker in several cardiovascular diseases. However, the relationship between TyG index and cardiac arrest (CA) remains unclear. The present study aimed to investigate the association of the TyG index with the occurrence and clinical outcomes of CA.

METHODS

In this retrospective, multicenter, observational study, critically ill patients, including patients post-CA, were identified from the eICU Collaborative Research Database and evaluated. The TyG index for each patient was calculated using values of triglycerides and glucose recorded within 24 h of intensive care unit (ICU) admission. In-hospital mortality and ICU mortality were the primary clinical outcomes. Logistic regression, restricted cubic spline (RCS), and correlation analyses were performed to explore the relationship between the TyG index and clinical outcomes. Propensity score matching (PSM), overlap weighting (OW), and inverse probability of treatment weighting (IPTW) were adopted to balance the baseline characteristics of patients and minimize selection bias to confirm the robustness of the results. Subgroup analysis based on different modifiers was also performed.

RESULTS

Overall, 24,689 critically ill patients, including 1021 patients post-CA, were enrolled. The TyG index was significantly higher in patients post-CA than in those without CA (9.20 (8.72-9.69) vs. 8.89 (8.45-9.41)), and the TyG index had a moderate discrimination ability to identify patients with CA from the overall population (area under the curve = 0.625). Multivariate logistic regression indicated that the TyG index was an independent risk factor for in-hospital mortality (OR = 1.28, 95% CI: 1.03-1.58) and ICU mortality (OR = 1.27, 95% CI: 1.02-1.58) in patients post-CA. RCS curves revealed that an increased TyG index was linearly related to higher risks of in-hospital and ICU mortality (P for nonlinear: 0.225 and 0.271, respectively). Even after adjusting by PSM, IPTW, and OW, the TyG index remained a risk factor for in-hospital mortality and ICU mortality in patients experiencing CA, which was independent of age, BMI, sex, etc. Correlation analyses revealed that TyG index was negatively correlated with the neurological status of patients post-CA.

CONCLUSION

Elevated TyG index is significantly associated with the occurrence of CA and higher mortality risk in patients post-CA. Our findings extend the landscape of TyG index in cardiovascular diseases, which requires further prospective cohort study.

A systematic review of global autopsy rates in all-cause mortality and young sudden death

Autopsy is the gold standard method for determining cause of death. Young sudden death (SD) is a prototype condition in which autopsy is universally recommended. The aim of this review was to quantify real-world global rates of autopsy in either all-cause death or young SD. A systematic review was conducted. Rates of autopsy in all-cause death and in young SD were determined in each country using scientific and commercial search engines. In total, 59 of 195 countries (30.3%) reported autopsy rates in all-cause death, with rates varying from 0.01%-83.9%. Almost all of these figures derived from academic publications rather than governmental statistics. Only 16 of 195 countries (8.2%) reported autopsy rates in the context of young SD, with reported rates ranging from 5%-100%. The definition of "young" was heterogeneous. No governmental statistics reported autopsy rates in young SD. Risks of bias included inability to verify reported figures, heterogeneity in reporting of clinical vs medicolegal autopsies, and the small number of studies identified overall, resulting in the consistent exclusion of low- and middle-income countries. In conclusion, most countries globally do not report autopsy rates in either all-cause death (69.7%) or in SD (92.8%). Without transparent reporting of autopsy rates, global burdens of disease and rates of sudden cardiac death cannot be reliably calculated.