Outrunning the grim reaper: longevity of the first 200 sub-4 min mile male runners.

OBJECTIVES: To determine the impact of running a sub-4 min mile on longevity. It was hypothesised that there would be an increase in longevity for runners who successfully completed a sub-4 min mile compared with the general population. METHODS: As part of this retrospective cohort study, the Sub-4 Alphabetic Register was used to extract the first 200 athletes to run a sub-4 min mile. Each runner's date of birth, date of their first successful mile attempt, current age (if alive) or age at death was compared with the United Nations Life Tables to determine the difference in each runner's current age or age at death with their country of origin-specific life expectancy. RESULTS: Of the first 200 sub-4 min mile runners (100% male), 60 were dead (30%) and 140 were still alive. Sub-4 min mile runners lived an average of 4.7 years beyond their predicted life expectancy (95% CI 4.7 to 4.8). When accounting for the decade of completion (1950s, 1960s or 1970s), the longevity benefits were 9.2 years (n=22; 95% CI 8.3 to 10.1), 5.5 years (n=88; 95% CI 5.3 to 5.7) and 2.9 years (n=90; 95% CI 2.7 to 3.1), respectively. CONCLUSION: Sub-4 min mile runners have increased longevity compared with the general population, thereby challenging the notion that extreme endurance exercise may be detrimental to longevity.

2024 CSANZ Position Statement on Indications, Assessment and Monitoring of Structural and Valvular Heart Disease With Transthoracic Echocardiography in Adults.

Transthoracic echocardiography (TTE) is the most widely available and utilised imaging modality for the screening, diagnosis, and serial monitoring of all abnormalities related to cardiac structure or function. The primary objectives of this document are to provide (1) a guiding framework for treating clinicians of the acceptable indications for the initial and serial TTE assessments of the commonly encountered cardiovascular conditions in adults, and (2) the minimum required standard for TTE examinations and reporting for imaging service providers. The main areas covered within this Position Statement pertain to the TTE assessment of the left and right ventricles, valvular heart diseases, pericardial diseases, aortic diseases, infective endocarditis, cardiac masses, pulmonary hypertension, and cardiovascular diseases associated with cancer treatments or cardio-oncology. Facilitating the optimal use and performance of high quality TTEs will prevent the over or under-utilisation of this resource and unnecessary downstream testing due to suboptimal or incomplete studies.

2024 HRS expert consensus statement on arrhythmias in the athlete: Evaluation, treatment, and return to play.

Youth and adult participation in sports continues to increase, and athletes may be diagnosed with potentially arrhythmogenic cardiac conditions. This international multidisciplinary document is intended to guide electrophysiologists, sports cardiologists, and associated health care team members in the diagnosis, treatment, and management of arrhythmic conditions in the athlete with the goal of facilitating return to sport and avoiding the harm caused by restriction. Expert, disease-specific risk assessment in the context of athlete symptoms and diagnoses is emphasized throughout the document. After appropriate risk assessment, management of arrhythmias geared toward return to play when possible is addressed. Other topics include shared decision-making and emergency action planning. The goal of this document is to provide evidence-based recommendations impacting all areas in the care of athletes with arrhythmic conditions. Areas in need of further study are also discussed.

The aortic paradox: a nationwide analysis of 523,994 individual echocardiograms exploring fatal aortic dissection.

BACKGROUND: Increasing aortic dilation increases the risk of aortic dissection. Nevertheless, dissection occurs at dimensions below guideline-directed cut-offs for prophylactic surgery. There is no current large-scale population imaging data assessing aortic dimensions before dissection. METHODS: Patients within the National Echo Database of Australia (NEDA) were stratified according to absolute, height-indexed and body surface area (BSA)-indexed aortic dimensions. Fatal thoracic aortic dissections (ICD-10-AM code I79) were identified via linkage with the National Death Index. RESULTS: 524,994 individuals were assessed, comprising patients with normal aortic dimensions (n = 460,992), mild dilation (n = 53,402), moderate dilation (n = 10,029) and severe dilation (n = 572). 274,992 (52.4%) were male, with median age 64 years and median follow-up time 6.9 years. 899 fatal aortic dissections occurred (normal diameter = 610, mildly-dilated aorta = 215, moderately-dilated =53 and severely-dilated = 21). Using normal aortas as the reference population, odds of fatal dissection increased with aortic diameter (mild = OR 3.05, 95% confidence interval (CI) 2.61-3.56; moderate = OR 4.0, 95% CI 3.02-5.30; severe = OR 28.72, 95% CI 18.44-44.72). Due to the much larger number of patients without severe aortic dilation, 97.7% of fatal aortic dissections occurred in non-severely dilated aortas. Following sensitivity analysis, severe aortic dilation was responsible for at most 24.4% of fatal aortic dissections. Results were robust for absolute, height-indexed or BSA-indexed aortic measurements. CONCLUSION: Although severe aortic dilatation is associated with a near-thirty-fold increase in fatal dissection, severely dilated aortas are implicated in only 2.3-24.4% of fatal dissections. This highlights the 'aortic paradox' and limitations of current guidelines. Future studies should seek to refine risk predictors in patients without severe aortic dilation.

International Criteria for Reporting Study Quality for Sudden Cardiac Arrest/Death Tool.

BACKGROUND: Studies reporting on the incidence of sudden cardiac arrest and/or death (SCA/D) in athletes commonly lack methodological and reporting rigor, which has implications for screening and preventative policy in sport. To date, there are no tools designed for assessing study quality in studies investigating the incidence of SCA/D in athletes. METHODS AND RESULTS: The International Criteria for Reporting Study Quality for Sudden Cardiac Arrest/Death tool (IQ-SCA/D) was developed following a Delphi process. Sixteen international experts in sports cardiology were identified and invited. Experts voted on each domain with subsequent moderated discussion for successive rounds until consensus was reached for a final tool. Interobserver agreement between a novice, intermediate, and expert observer was then assessed from the scoring of 22 relevant studies using weighted and unweighted κ analyses. The final IQ-SCA/D tool comprises 8 domains with a summated score of a possible 22. Studies are categorized as low, intermediate, and high quality with summated IQ-SCA/D scores of ≤11, 12 to 16, and ≥17, respectively. Interrater agreement was "substantial" between all 3 observers for summated IQ-SCA/D scores and study categorization. CONCLUSIONS: The IQ-SCA/D is an expert consensus tool for assessing the study quality of research reporting the incidence of SCA/D in athletes. This tool may be used to assist researchers, reviewers, journal editors, and readers in contextualizing the methodological quality of different studies with varying athlete SCA/D incidence estimates. Importantly, the IQ-SCA/D also provides an expert-informed framework to support and guide appropriate design and reporting practices in future SCA/D incidence trials.

Prognostic and functional importance of both overt and subclinical left ventricular systolic dysfunction in systemic sclerosis.

OBJECTIVES: To quantify the frequency and clinical implications of systemic sclerosis (SSc)-associated left ventricular function (LV) impairment. METHODS: Australian Scleroderma Cohort Study participants meeting ACR/EULAR criteria for SSc with ≥1 echocardiographic LVEF measurement were included. Overt LV dysfunction was indicated by reduced LV ejection fraction (LVEF) and subclinical LV dysfunction was measured using impaired LV global longitudinal strain (LV-GLS>-16 %). Those with secondary causes of LV dysfunction (myocardial ischaemia, valvulopathy and pulmonary arterial hypertension) were excluded. Chi-squared tests, two-sample t-tests or Wilcoxon rank-sum tests were used for between-group comparison as appropriate. Generalised estimating equations(GEE) were used to model longitudinal data. Kaplan-Meier and Cox proportional hazard models were used for survival analyses. RESULTS: Of 1141 participants with no co-morbid cardiac disease, 2.4 % ever recorded a LVEF<50 %, while only 0.6 % ever recorded a LVEF≤40 %. LV-GLS data were available for 90 % of participants at one centre (n = 218). Impaired LV-GLS was detected in 21 % despite LVEF≥50 %. Those with a LVEF<50 % were more frequently male (p = 0.01) with dcSSc (p < 0.01), higher inflammatory markers (p < 0.02) and skeletal muscle disease (p < 0.05). In multivariable analyses, recording a LVEF<50 % was associated with increased mortality (HR2.3, 95 %CI1.0-4.8, p = 0.04). Impaired LV-GLS was also associated with poorer survival in univariable analyses (HR3.4, 95 %CI1.0-11.8, p = 0.05). Those with a LVEF<50 % more frequently recorded WHO Class III/IV dyspnoea (OR3.5, 95 %CI1.6-7.7, p < 0.01), with shorter six-minute walk distance (p = 0.01), higher Health Assessment Questionnaire-Disability Index scores (p < 0.01) and lower Short Form-36 Physical Component Summary scores (p = 0.02). Increased dyspnoea (WHO Class III/IV dyspnoea; OR3.6, 95 %CI1.4-9.2, p < 0.01) was also seen in those with impaired LV-GLS. CONCLUSIONS: Both overt and subclinical SSc-associated LV dysfunction are associated with worse survival and impaired physical function. The frequency of abnormal LV-GLS in those with consistently normal LVEF suggests an under-appreciated burden of subtle LV systolic dysfunction in SSc that has a significant impact on patient symptomatology.

Characterizing the influence of cardiorespiratory fitness on left atrial size and function in the general population.

Increased left atrial (LA) size and reduced LA function have been associated with heart failure and atrial fibrillation (AF) in at-risk populations. However, atrial remodeling has also been associated with exercise training and the relationship between fitness, LA size, and function has not been defined across the fitness spectrum. In a cross-sectional study of 559 ostensibly healthy participants, comprising 304 males (mean age, 46 ± 20 yr) and 255 females (mean age, 47 ± 15 yr), we sought to define the relationship between cardiorespiratory fitness (CRF), LA size, and function. We also aimed to interrogate sex differences in atrial factors influencing CRF. Echocardiographic measures included biplane measures of LA volumes indexed to body surface area (LAVi) and atrial deformation using two-dimensional speckle tracking. CRF was measured as peak oxygen consumption (V̇o2peak) during cardiopulmonary exercise testing (CPET). Using multivariable regression, age, sex, weight, and LAVi (P < 0.001 for all) predicted V̇o2peak (P < 0.001, R2 = 0.66 for combined model). After accounting for these variables, heart rate reserve added strength to the model (P < 0.001, R2 = 0.74) but LA strain parameters did not predict V̇o2peak. These findings add important nuance to the perception that LA size is a marker of cardiac pathology. LA size should be considered in the context of fitness, and it is likely that the adverse prognostic associations of increased LA size may be confined to those with LA enlargement and low fitness.NEW & NOTEWORTHY Left atrial (LA) structure better predicts cardiorespiratory fitness (CRF) than LA function. LA function adds little statistical value to predictive models of peak oxygen uptake (V̇o2peak) in healthy individuals, suggesting limited discriminatory for CRF once LA size is factored. In the wider population of ostensibly healthy individuals, the association between increased LA volume and higher CRF provides an important counter to the association between atrial enlargement and heart failure symptoms in those with cardiac pathology.

Determinants of Impaired Peak Oxygen Uptake in Breast Cancer Survivors: JACC: CardioOncology Primer.

•Exercise intolerance is common among breast cancer survivors.•Exercise intolerance in breast cancer survivors is related to cardiac, vascular, and skeletal muscle impairments.•Holistic rehabilitation or pharmacological therapies are needed to address these impairments.

Physiological determinants of decreased peak leg oxygen uptake in chronic disease: a systematic review and meta-analysis.

This systematic review and meta-analysis examined the physiological mechanisms responsible for lower peak exercise leg oxygen uptake (V̇o2) in patients with chronic disease. Studies measuring peak leg V̇o2 (primary outcome) and its physiological determinants during large (cycle) or small muscle mass exercise (single-leg knee extension, SLKE) in patients with chronic disease were included in this meta-analysis. Pooled estimates for each outcome were reported as a weighted mean difference (WMD) between chronic disease and controls. We included 10 studies that measured peak leg V̇o2 in patients with chronic disease (n = 109, mean age: 45 yr; encompassing chronic obstructive pulmonary disease, COPD, heart failure with reduced ejection fraction, HFrEF, or chronic renal failure, RF) and age-matched controls (n = 88). In pooled analysis, peak leg V̇o2 (WMD; -0.23 L/min, 95% CI: -0.32 to -0.13), leg oxygen (O2) delivery (WMD: -0.27 L/min, 95% CI: -0.37 to -0.17), and muscle O2 diffusive conductance (WMD: -5.2 mL/min/mmHg, 95% CI: -7.1 to -3.2) were all significantly lower during cycle and SLKE exercise in chronic disease versus controls. These results highlight that during large and small muscle mass exercise in patients with COPD, HFrEF, or RF, there is no single factor causing peak V̇o2 limitations. Specifically, the lower peak V̇o2 in these pathologies is due to not only the expected impairments in convective O2 delivery but also impairments in muscle oxygen diffusive transport from capillary to mitochondria. Whether impaired muscle O2 transport is caused solely by inactivity or additional muscle pathology remains in question.NEW & NOTEWORTHY Peripheral (skeletal muscle and vasculature) factors contribute significantly to reduced exercise capacity during both large and small muscle mass exercise in chronic diseases such as COPD, HFrEF, or RF and should be important targets of therapy in addition to the primary organs (lungs, heart, and kidneys) affected by disease.

Integrating Cardio-Oncology Across the Research Pipeline, Policy, and Practice in Australia-An Australian Cardiovascular Alliance Perspective.

Over 18 million people worldwide were diagnosed with cancer in 2020, including over 150,000 people in Australia. Although improved early detection and treatment have increased the survival rates, cardiotoxic treatment and inadequate management of cardiovascular risk factors have resulted in cardiovascular disease (CVD) being one of the leading causes of non-cancer-related death and disability among cancer survivors. International guidelines outline the standards of care for CVD risk surveillance and management. However, Australian cardio-oncology policies and clinical guidelines are limited. There is increasing growth of cardio-oncology research in Australia and support from leading Australian professional bodies and advocacy and research networks, including the Cardiac Society of Australia and New Zealand, the Clinical Oncology Society of Australia, the National Heart Foundation of Australia, and the Australian Cardiovascular Alliance (ACvA). Thus, opportunities to drive multidisciplinary cardio-oncology initiatives are growing, including grant funding, position statements, and novel research to inform new policies. The ACvA has a unique flagship structure that spans the translational research pipeline from drug discovery to implementation science. This article aims to highlight how multidisciplinary cardio-oncology innovations could intersect with the seven ACvA flagships, and to showcase Australian achievements in cardio-oncology thus far. We summarise eight key priority areas for future cardio-oncology research that emerged. These strategies will strengthen cardio-oncology research and care in Australia, and drive new guidelines, policies, and government initiatives to ensure equity in health outcomes for all cardio-oncology patients.

Contribution of Left Ventricular Diastolic Dysfunction to Survival and Breathlessness in Systemic Sclerosis-Associated Interstitial Lung Disease.

OBJECTIVE: To explore the effect of left ventricular (LV) diastolic dysfunction (LVDD) in systemic sclerosis (SSc)-associated interstitial lung disease (ILD), and to investigate SSc-specific associations and clinical correlates of LVDD. METHODS: There were 102 Australian Scleroderma Cohort Study participants with definite SSc and radiographic ILD included. Diastolic function was classified as normal, indeterminate, or abnormal according to 2016 American Society of Echocardiography/European Association of Cardiovascular Imaging guidelines for assessment of LV diastolic function. Associations between clinical features and patient- and physician-reported dyspnea were evaluated using logistic regression. Survival analyses were performed using Kaplan-Meier survival estimates and Cox regression modeling. RESULTS: LVDD was identified in 26% of participants, whereas 19% had indeterminate and 55% had normal diastolic function. Those with ILD and LVDD had increased mortality (hazard ratio 2.4, 95% CI 1.0-5.7; P = 0.05). After adjusting for age and sex, those with ILD and LVDD were more likely to have severe dyspnea on the Borg Dyspnoea Scale (odds ratio [OR] 2.6, 95% CI 1.0-6.6; P = 0.05) and numerically more likely to record World Health Organization Function Class II or higher dyspnea (OR 4.2, 95% CI 0.9-20.0; P = 0.08). Older age (95% CI 1.0-6.4; P = 0.05), hypertension (OR 5.0, 95% CI 1.8-13.8; P < 0.01), and ischemic heart disease (OR 4.8, 95% CI 1.5-15.7; P < 0.01) were all associated with LVDD, as was proximal muscle atrophy (OR 5.0, 95% CI 1.9-13.6; P < 0.01) and multimorbidity (Charlson Comorbidity Index scores ≥ 4, OR 3.0, 95% CI 1.1-8.7; P = 0.04). CONCLUSION: LVDD in SSc-ILD is more strongly associated with traditional LVDD risk factors than SSc-specific factors. LVDD is associated with worse dyspnea and survival in those with SSc-ILD.

Sex disparities in bystander defibrillation for out-of-hospital cardiac arrest.

Background: Previous studies have suggested that females experiencing out-of-hospital cardiac arrest (OHCA) receive lower rates of both bystander cardiopulmonary resuscitation (CPR) and defibrillation compared to males. Whether this disparity has improved over time is unknown. Methods: A state-wide OHCA registry in Victoria, Australia collected data over twenty years (2002-2021) regarding rates of bystander interventions in OHCA. Characteristics and outcomes of each OHCA were compared with logistic regression according to sex and time (defined in two-year periods). Results: 32,502 OHCAs were included (69.7% male). Both bystander CPR and defibrillation rates increased for females over time (p < 0.0001). There was no sex disparity in receipt of bystander CPR after adjustment for baseline differences. Females were less likely than males to receive bystander defibrillation, with sex disparity increasing from 2010 onwards (adjOR 0.26 (95%CI 0.09-0.80) in 2020-21 for females compared to males). Conclusion: Initiatives to increase bystander CPR and defibrillation have resulted in higher overall rates of bystander interventions in the last two decades and no significant sex differences in provision of bystander CPR. However, females receive less bystander defibrillation than males, and sex disparity is increasing. Strategies to promote bystander defibrillation in females experiencing OHCA with a shockable rhythm should be a priority.

A Review on the Role of Exercise Training to Prevent a Decline in Cardiorespiratory Fitness and Cardiac Function in Breast Cancer Survivors.

PURPOSE: Improvements in diagnosis and treatment mean that the long-term health of breast cancer survivors (BCS) is increasingly dictated by cardiovascular comorbidities. This is partly a consequence of exposure to cardiotoxic therapies, which result in cardiac dysfunction and decreased cardiorespiratory fitness (CRF). Exercise training (ExT) is a key therapeutic strategy for secondary prevention and increasing CRF in adults with established cardiovascular disease. Exercise-based cardio-oncology rehabilitation (CORE) has been proposed as an emerging strategy to address CRF and cardiac impairment in BCS. This review aims to (1) provide an overview of the impact of breast cancer therapy on CRF; (2) provide an up-to-date summary of the effects of ExT on CRF and cardiac function in BCS undergoing cardiotoxic therapy; and (3) discuss how traditional ExT approaches can be adapted for BCS undergoing therapy. REVIEW METHODS: A literature review was performed based on an intensive literature search for systematic reviews and meta-analyses, randomized and non-randomized controlled trials and single-arm trials investigating the impact of exercise training or cardiac rehabilitation on CRF and/or cardiac function in BCS who are undergoing or have completed cardiotoxic cancer therapy. SUMMARY: Overall, current evidence suggests that ExT induces clinically meaningful benefits for CRF in BCS during and after therapy. There is also emerging evidence that ExT can improve peak exercise measures of cardiac function; however, there is a need for further research to understand how to adapt these effective ExT approaches into clinical CORE-based settings.

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.

Reduced Ejection Fraction in Elite Endurance Athletes: Clinical and Genetic Overlap With Dilated Cardiomyopathy.

BACKGROUND: Exercise-induced cardiac remodeling can be profound, resulting in clinical overlap with dilated cardiomyopathy, yet the significance of reduced ejection fraction (EF) in athletes is unclear. The aim is to assess the prevalence, clinical consequences, and genetic predisposition of reduced EF in athletes. METHODS: Young endurance athletes were recruited from elite training programs and underwent comprehensive cardiac phenotyping and genetic testing. Those with reduced EF using cardiac magnetic resonance imaging (defined as left ventricular EF <50%, or right ventricular EF <45%, or both) were compared with athletes with normal EF. A validated polygenic risk score for indexed left ventricular end-systolic volume (LVESVi-PRS), previously associated with dilated cardiomyopathy, was assessed. Clinical events were recorded over a mean of 4.4 years. RESULTS: Of the 281 elite endurance athletes (22±8 years, 79.7% male) undergoing comprehensive assessment, 44 of 281 (15.7%) had reduced left ventricular EF (N=12; 4.3%), right ventricular EF (N=14; 5.0%), or both (N=18; 6.4%). Reduced EF was associated with a higher burden of ventricular premature beats (13.6% versus 3.8% with >100 ventricular premature beats/24 h; P=0.008) and lower left ventricular global longitudinal strain (-17%±2% versus -19%±2%; P<0.001). Athletes with reduced EF had a higher mean LVESVi-PRS (0.57±0.13 versus 0.51±0.14; P=0.009) with athletes in the top decile of LVESVi-PRS having an 11-fold increase in the likelihood of reduced EF compared with those in the bottom decile (P=0.034). Male sex and higher LVESVi-PRS were the only significant predictors of reduced EF in a multivariate analysis that included age and fitness. During follow-up, no athletes developed symptomatic heart failure or arrhythmias. Two athletes died, 1 from trauma and 1 from sudden cardiac death, the latter having a reduced right ventricular EF and a LVESVi-PRS >95%. CONCLUSIONS: Reduced EF occurs in approximately 1 in 6 elite endurance athletes and is related to genetic predisposition in addition to exercise training. Genetic and imaging markers may help identify endurance athletes in whom scrutiny about long-term clinical outcomes may be appropriate. REGISTRATION: URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=374976&isReview=true; Unique identifier: ACTRN12618000716268.

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.

The challenge of risk stratification in hypertrophic cardiomyopathy: Clinical, genetic and imaging insights from a quaternary referral centre.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is the commonest genetic cardiomyopathy and may result in sudden cardiac death (SCD). Clinical risk stratification scores are utilised to estimate SCD risk and determine potential utility of a primary prevention implantable cardioverter defibrillator (ICD). METHODS: Patients with a confirmed diagnosis of HCM from a quaternary HCM service were defined according to clinical characteristics, genetic profiles and cardiac imaging results. European Risk-SCD score and American Heart Association / American College of Cardiology (AHA/ACC) Score were calculated. The primary outcome was cardiac arrest. RESULTS: 380 patients with HCM were followed up for a median of 6.4 years. 18 patients (4.7%) experienced cardiac arrest, with predictive factors being younger age (37.2 vs 54.4 years, p = 0.0041), unexplained syncope (33.3% vs 9.4%, p = 0.007), non-sustained ventricular tachycardia (50.0% vs 12.7%, p < 0.0001), increased septal thickness (21.5 vs 17.5 mm, p = 0.0003), and presence of a sarcomeric gene mutation (100.0% vs 65.8%, p = 0.038). The Risk-SCD and AHA/ACC scores had poor agreement (kappa coefficient 0.38). Risk-SCD score had poor sensitivity (44.4%), classifying 55.6% of patients with cardiac arrest as low-risk but was highly specific (93.7%). AHA/ACC risk score did not discriminate between groups significantly. 20 patients (5.3%) died, with most >60-year-olds having a non-cardiac cause of death (p = 0.0223). CONCLUSION: This study highlights limited (38%) agreement between the Risk-SCD and AHA/ACC scores. Most cardiac arrests occurred in ostensibly low or medium-risk patients under both scores. Appropriate ICD selection remains challenging. Incorporating newer risk markers such as HCM genotyping and myocardial fibrosis quantification by cardiac MRI may assist future risk refinement.