AIMS:This study aims to define the association between severe coronary artery disease and widespread atherosclerosis in younger individuals. METHODS AND RESULTS:Individuals aged 1-50 years with sudden cardiac death (SCD) from 2019 to 2023, autopsy-proven to be due to coronary artery disease, were identified using the state-wide End Unexplained Cardiac Death (EndUCD) registry. Presence of extra-coronary atherosclerosis greater than modified American Heart Association Class III was assessed in four arterial beds (aorta, carotid, renal, and femoral arteries). A total of 3044 individuals experienced SCD; 356 were due to coronary artery disease, and 62 (17.4%) had extra-coronary plaque. Plaque was identified in the aorta (n = 61 patients, 17.1%), carotid arteries (n = 9, 2.5%), iliofemoral arteries (n = 11, 3.1%), and renal arteries (n = 6 patients, 1.7%). Features associated with extra-coronary plaque were older age (median 47.8 vs. 44.4 years, P = 0.0002) and hypertension (30.7 vs. 18.7%, P = 0.035). Patients with extra-coronary plaque had higher rates of cardiomegaly (67.9 vs. 50.7%, P = 0.019), cardiac fibrosis indicative of previous myocardial infarction (46.8 vs. 31.0%, P = 0.017), and multi-vessel coronary disease (71.7 vs. 55.9%, P = 0.024). CONCLUSION:Fewer than one in five people aged 1-50 years experiencing SCD from a coronary cause exhibited extra-coronary plaque, suggesting that in young people, severe atherosclerosis is not necessarily a concurrent systemic disease. This may limit the utility of screening for carotid or aortic plaque to predict coronary atherosclerosis on an individual level. Individuals with extra-coronary plaque were older with more established coronary disease.

Background: Arrhythmia induced cardiomyopathy (AiCM) is reversible, and catheter ablation has become the standard treatment for most arrhythmias. Given the potential overlap between different forms of cardiomyopathy and the frequent absence of documentation of slow tachycardia before first presentation, the diagnosis of AiCM can often made only in retrospective. Methods: A single center retrospective study including patients who had ablation for presumed AiCM after January 2011 to assess the outcomes of ablation, and the final diagnosis. Patient demographics, types of arrhythmias, procedural details and follow up data were obtained from medical records. Results: 20 patients (10 female) were included in the study with the following distribution of arrhythmias: Atrial Ectopic Tachycardia (AET) = 8, Permanent Junctional Reciprocating Tachycardia (PJRT) = 6, Ventricular Tachycardia = 3, Premature Ventricular Contraction = 1, Atrial Flutter = 1, Atrioventricular Reciprocating Tachycardia = 1. 13/20 (65%) had successful primary ablation resulting in recovery of function and/or discontinuation of antiarrhythmic medication. In 8/20 (20%) ablation was performed under mechanical circulatory support, 3/20 (15%) had arrhythmia recurrence. Overall long-term control of arrhythmia with ablation alone was achieved in 17/20 (85%). One AET patient showed no recovery of function despite successful ablation, consequently requiring heart transplant due to later confirmed gene-positive cardiomyopathy. Overall, 19 patients (95%) showed normal cardiac function at the end of study period with diagnosis of AiCM. There was one significant complication with AV block due to RF ablation on ECMO in a newborn with PJRT. Conclusions: When carefully selected, ablation for pediatric patients in AICM has a high success rate including long term recovery of the ventricular function, even for small patients. Very rarely ventricular function will not recover despite successful ablation as genetic cardiomyopathies can present with secondary arrhythmia.

Background:Out-of-hospital cardiac arrest (OHCA) on the toilet has been reported to be common and possibly driven by straining or vagal stimulus. Toilet-associated OHCA may also create a challenging resuscitation environment. Methods:The national Danish sudden death registry and state-wide Australian End Unexplained Cardiac Death (EndUCD) registry were examined. Persons with a fatal OHCA aged 5-50 years with autopsy-confirmed cardiac or unascertained aetiology were included. Resuscitation-related, aetiological and forensic factors were compared between persons experiencing fatal toilet-associated OHCA versus elsewhere. A composite variable of physiological conditions creating pressure-load or pressure-sensitivity was created, comprising hypertrophic cardiomyopathy, aortic stenosis/coarctation, and aortic aneurysm/dissection. Results:Of 2,463young persons, 75 (3.0 %) experienced toilet-associated fatal OHCA while 2,388 (97.0 %) experienced out-of-toilet OHCA. Australians experienced toilet-associated OHCA 1.7 times more frequently than Danes (4.1 % vs 2.4 %, p = 0.016). Toilet-associated OHCA was less frequently witnessed (13.3 % vs 32.1 %, p = 0.001), with lower rates of bystander cardiopulmonary resuscitation (32.0 % vs 55.7 %, p < 0.0001) and shockable rhythm (5.9 % vs 23.8 %, p = 0.003) compared to non-toilet OHCA. Toxicological results were more frequently positive for illicit substances in toilet-associated OHCA (32.8 % vs 16.3 %, p < 0.0001). No differences were identified in OHCA aetiology, including rates of the composite variable of aetiologies such as hypertrophic cardiomyopathy and aortic dissection. Conclusion:3.0 % of young fatal OHCA of cardiac aetiology is toilet-associated, with almost double the rates of toilet-associated OHCA in Australia compared to Denmark. No differences in OHCA aetiology were identified in toilet-associated OHCA. Resuscitation-related factors were adverse in toilet-related OHCA, highlighting the need for innovative ways to recognise and respond to toilet-associated OHCA.

Background: Autopsy, the gold standard for determining the cause of death, is declining globally. Significant differences exist between clinical diagnoses and those revealed at autopsy. Evidence of disparities in autopsy rates between different patient groups has previously been reported. Objective: To describe contemporary trends and disparities in autopsy rates according to sex, race, and urbanization, with particular attention to patients who have died because of cardiovascular disease (CVD). Methods: We accessed the Center for Disease Control Wide-Ranging Online Data for Epidemiological Research “Underlying Cause of Death” dataset for 2003 to 2020, to assess trends in autopsy rates in all-comers and for different subgroups stratified by sex, race, and degree of urbanization. Further primary and subgroup analysis was performed independently by the International Classification of Diseases, Tenth Revision cause of death criteria by chapter, subchapter, and specific diseases of interest. Linear regression was used to assess trends over time, with a significant coefficient considered evidence of temporal trend. Results: Annual autopsy rates decreased across the time period in all-comers, with an average autopsy rate of 3.66% (P < .001); however, this relationship was not demonstrated in CVDs. Men undergo autopsy more frequently than women, though autopsy rates in women with CVD are increasing (P = .011). Patients of non-White ethnicity and in metropolitan areas undergo autopsy at higher rates. Increasing autopsy rates are seen in ischemic heart disease (P < .001). Conclusion: Autopsy is decreasing in the United States; however, trends differ depending on patient factors (sex, ethnicity), social factors (degree of urbanization), and disease factors.

Background Alpine tourism annually attracts over 100 million visitors globally. Age and cardiovascular comorbidities in alpine tourists are increasing, and rates of out-of-hospital cardiac arrest (OHCA) have been hypothesized to be higher due to exertion and physiological stress. Methods Cases of alpine OHCA from 2002 to 2021 were identified from the statewide Victorian Ambulance Cardiac Arrest Registry. Alpine and nonalpine OHCA characteristics were compared. Causes of alpine OHCA were obtained from hospital discharge diagnoses and the National Coronial Information System. Results Approximately 15.3 million alpine visits were recorded over the time period, during which 13 alpine OHCAs occurred (0.04% of 32,179 OHCAs, 0.8 OHCAs per million alpine visits). Compared with nonalpine OHCAs in a public setting, alpine OHCA patients were younger (median age 52 years vs 63 years, P = .0373), with higher rates of bystander defibrillation (54.5% vs 13.5%, P < .0001). Survival to hospital discharge did not significantly differ between alpine (38.5%) and nonalpine OHCA patients. Ischemic heart disease was the commonest identified cause of alpine OHCA in both survivors and nonsurvivors. Conclusion Alpine OHCA is very rare in Australia, accounting for 1 in 5000 OHCAs and fewer than 1 in a million ski field visitors. Despite remoteness and access challenges, alpine OHCA survival is high, driven by prognostically favorable arrest-related factors and coordinated local systems of care prioritizing early bystander intervention.

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. (c) 2023 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

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.

Numerous studies have established that the commonest contemporary finding in young sudden cardiac death is a negative autopsy – so-called 'sudden arrhythmic death syndrome' (SADS) (1). However, no specific International Classification of Disease (ICD) ICD-10 code described the entity of SADS.

Abstract Background The association between severe coronary artery disease and widespread atherosclerosis in younger individuals remains uncertain. Purpose To characterise the association between severe (fatal) coronary disease and extra-cardiac atherosclerosis in a population of young and middle-aged individuals. Methods Individuals aged 1-50 years with sudden cardiac death (SCD) from 2019-23, autopsy-proven to be due to coronary artery disease, were identified using the state-wide EndUCD registry. The presence of extra-coronary atherosclerosis greater than modified American Heart Association class III was documented in five arterial beds (intra-cerebral vessels, carotid arteries, aorta, renal and femoral arteries). Results Of 3,044 individuals who experienced SCD, 372 were due to coronary artery disease and 71 of these (19.1%) had extra-coronary plaque. Plaque was identified in aorta (68/372 patients, 18.3%), carotid arteries (11/372, 3.0%), iliofemoral arteries (11/372, 3.0%), intracerebral arteries (4/157 patients who underwent examination of the brain, 2.6%) and renal arteries (7/372 patients, 1.9%). 51 patients (13.7%) had plaque in ≥2 arterial beds in addition to their coronary disease. Predictors of extra-coronary plaque were older age (median 47.7 vs 44.4 years, p<0.0001), hypertension (32.3% vs 18.9%, p=0.013), and previous percutaneous coronary intervention (9.9% vs 3.0%, p=0.01). Patients with extra-coronary plaque had higher rates of cardiomegaly (68.8% vs 51.1%, p=0.01), cardiac fibrosis indicative of previous myocardial infarction (49.3% vs 31.9%, p=0.006) and multi-vessel coronary disease (73.5% vs 55.6%, p=0.007). Conclusion Only 1 in 5 people aged 1-50 years experiencing SCD from a coronary cause exhibit extra-coronary plaque. This limits the utility of screening for carotid or aortic plaque to predict coronary atherosclerosis. Individuals with extra-coronary plaque had a higher burden of cardiovascular risk factors and more established coronary disease.

Abstract Background Identifying factors to improve survival following out-of-hospital cardiac arrest (OHCA) is important. Many OHCA registries do not document the underlying cause of OHCA and therefore cannot provide insights according to specific arrest aetiology. The aim of this study was to assess survivability of OHCA according to arrest aetiology. Methods A state-wide registry identified all patients aged 1 to 50 years who experienced OHCA in Victoria, Australia from April 2019 to April 2023. OHCA was ambulance-defined with cause of OHCA determined by adjudication against autopsy or hospital data. OHCA aetiology was classified into four categories; non-cardiac, coronary, cardiomyopathy or other cardiac (including unascertained cause). Results 2686 patients experienced OHCA (non-cardiac=1305, 48.6%, coronary=585, 21.8%, cardiomyopathy=250, 9.3%, other cardiac=537(282 unascertained), 20.0%), of whom 250 (9.3%) survived. Patients in the coronary group were older (median 45 years [interquartile range 40-48 years], p=0.0001), more likely to be male (83.6%, p<0.0001), have a witnessed arrest (44.6%, p<0.0001) and have an initial shockable rhythm (48.2%, p<0.0001) when compared to other categories. Using the non-cardiac group as the reference group, adjusted odds ratio of survival (95% CI) were 1.65 (0.86-3.19) for cardiomyopathy, 2.51 (1.55-4.07) for other cardiac and 4.03 (2.51-6.49) for coronary causes of OHCA. Conclusion Odds of survival to hospital discharge following OHCA were four times higher in OHCA of coronary aetiology when compared with non-cardiac OHCA. Ongoing research into OHCA according to aetiology is needed to define subgroups, benchmark resuscitation performance more appropriately and identify patterns according to specific aetiologies to improve survival outcomes.

BackgroundAn uncertain proportion of patients with acute coronary syndrome (ACS) also experience out-of-hospital cardiac arrest (OHCA). Predictors of OHCA in ACS remain unclear and vulnerable to selection bias as pre-hospital deceased patients are usually not included.MethodsData on patients aged 18–50 years from a percutaneous coronary intervention (PCI) and OHCA registry were combined to identify all patients experiencing OHCA due to ACS (not including those managed medically or who proceeded to cardiac surgery). Clinical, angiographic and forensic details were collated. In-hospital and post-discharge outcomes were compared between OHCA survivors and non-OHCA ACS patients.ResultsOHCA occurred in 6.0% of ACS patients transported to hospital and 10.0% of all ACS patients. Clinical predictors were non-diabetic status (p = 0.015), non-obesity (p = 0.004), ST-elevation myocardial infarction (p < 0.0001) and left main (p < 0.0002) or left anterior descending (LAD) coronary artery (p < 0.0001) as culprit vessel. OHCA patients had poorer in-hospital clinical outcomes, including longer length of stay and higher pre-procedural intubation, cardiogenic shock, major adverse cardiovascular events, bleeding, and mortality (p < 0.0001 for all). At 30 days, OHCA survivors had equivalent cardiac function and return to premorbid independence but higher rates of anxiety/depression (p = 0.029).ConclusionOHCA complicates approximately 10% of ACS in the young. Predictors of OHCA are being non-diabetic, non-obese, having a STEMI presentation, and left main or LAD coronary culprit lesion. For OHCA patients surviving to PCI, higher rates of in-hospital complications are observed. Despite this, recovery of pre-morbid physical and cardiac function is equivalent to non-OHCA patients, apart from higher rates of anxiety/depression.

Myocarditis has previously been identified as a major cause of sudden cardiac death (SCD) in young adults. A state-wide prospective out-of-hospital cardiac arrest registry linking ambulance, hospital, and forensic data identified all patients aged 1 to 50 years who experienced a sudden cardiac arrest from April 2019 to April 2022 in Victoria, Australia. All patients with myocarditis as a primary cause were identified. Histological findings for individuals who underwent autopsy were examined. Of 2,410 patients who experienced cardiac arrest during the study period, 14 (0.58%) had myocarditis. Average age was 40.5 years (range, 22.1–50.5); 50% were male and 50% were female. Two patients survived, and the remaining 12 had histological features of myocarditis confirmed on autopsy. Initial arrest rhythm was identified for 13 patients, with eight patients (61.5%) in asystole and five patients (38.5%) in ventricular fibrillation, two of whom survived. Seven patients (50%) had toxicology positive for illicit substances, of which the most common was cannabis (four patients, 28.5%). Histological patterns included lymphocytic myocarditis (eight patients, 66.7%), giant cell myocarditis (two patients, 16.7%), mixed inflammatory infiltrate in a patient with mixed drug toxicity (one patient), and neutrophilic micro-abscesses associated with bacterial infection (one patient). Four patients (33%) had significant coronary artery disease noted on autopsy, but this was a competing cause of death for one patient. Myocarditis is found in a small proportion of young sudden cardiac arrest cases. Histological patterns for patients with SCD are diverse, with giant cell myocarditis less common than lymphocytic myocarditis.

Cardiac implantable electronic device (CIED) remote transmissions are an integral part of longitudinal follow-up in pediatric and adult congenital heart disease (ACHD) patients. To evaluate baseline CIED remote monitoring (RM) data among pediatric and ACHD centers prior to implementation of a Pediatric and Congenital Electrophysiology Society (PACES)-sponsored quality improvement (QI) project. This is a cross-sectional study of baseline CIED RM. Centers self-reported baseline data: individual center RM compliance was defined as high if there was > 80% achievement and low if < 50%. A total of 22 pediatric centers in the USA and Australia submitted baseline data. Non-physicians were responsible for management of the RM program in most centers: registered nurse (36%), advanced practice provider (27%), combination (23%), and third party (9%). Fifteen centers (68%) reported that > 80% of their CIED patients are enrolled in RM and only two centers reported < 50% participation. 36% reported high compliance of device transmission within 14 days of implant and 77% of centers reported high compliance of CIED patients enrolled in RM. The number of centers achieving high compliance differed by device type: 36% for pacemakers, 50% for ICDs, and 55% for Implantable Cardiac Monitors (ICM). All centers reported at least 50% adherence to recommended follow-up for PM and ICD, with 23% low compliance rate for ICMs. Based on this cross-sectional survey of pediatric and ACHD centers, compliance with CIED RM is sub-optimal. The PACES-sponsored QI initiative will provide resources and support to participating centers and repeat data will be evaluated after PDSA cycles.