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.

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.

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.

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.

A two-point strategy to clarify prognosis in >80 year olds experiencing out of hospital cardiac arrest.

BACKGROUND: The global population is aging, with the number of ≥80-year-olds projected to triple over the next 30 years. Rates of out-of-hospital cardiac arrest (OHCA) are also increasing within this age group. METHODS: The Victorian Ambulance Cardiac Arrest Registry was utilised to identify OHCAs in patients aged ≥80 years between 2002-2021. Predictors of survival to discharge were defined and a prognostic score derived from this cohort. RESULTS: 77,628 patients experienced OHCA of whom 25,269 (32.6%) were ≥80 years (80-90 years = 18,956; 90-100 years = 6,148; >100 years = 209). The number of patients ≥80 years increased over time both absolutely (p = 0.002) and proportionally (p = 0.028). 619 (2.4%) patients survived to discharge without change over time. Older ages had no difference in witnessed OHCA status but were less likely to have shockable rhythm (OR 0.50 (95% CI 0.44-0.57) for 90-100-year-olds, OR 0.28 (95% CI 0.12-0.63) for 90-100-year-olds). If OHCA was witnessed and there was a shockable rhythm then survival was 14%; if one factor was present survival was 5-6% and if neither factor was present, survival was 0.09%. These survival rates enabled derivation of a simplified prognostic assessment score - the '15/5/0' score - highly comparable to a previously-published American cohort. CONCLUSIONS: Elderly OHCA rates have increased to one-third of caseload. The most important factors predicting survival were whether the OHCA was witnessed and there was a shockable rhythm. We present a simple two-point '15/5/0' prognostic score defining which patients will gain most from advanced resuscitative measures.

Understanding Exercise Capacity: From Elite Athlete to HFpEF.

Exercise capacity is a spectrum that reflects an individual's functional capacity and the dynamic nature of cardiac remodelling along with respiratory and skeletal muscle systems. The relationship of increasing physical activity, increased cardiac mass and volumes, and improved cardiorespiratory fitness (CRF) is well established in the endurance athlete. However, less emphasis has been placed on the other end of the spectrum, which includes individuals with a more sedentary lifestyle and small hearts who are at increased risk of functional disability and poor clinical outcomes. Reduced CRF is an independent predictor of all-cause mortality and cardiovascular events determined by multiple inter-related exogenous and endogenous factors. In this review, we explore the relationship of physical activity, cardiac remodelling, and CRF across the exercise spectrum, emphasising the critical role of cardiac size in determining exercise capacity. In contrast to the large compliant left ventricle of the endurance athlete, an individual with a lifetime of physical inactivity is likely to have a small, stiff heart with reduced cardiac reserve. We propose that this might contribute to the development of heart failure with preserved ejection fraction in certain individuals, and is key to understanding the link between low CRF and increased risk of heart failure.

Epidemiology of pediatric out-of-hospital cardiac arrest compared with adults.

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) is associated with ∼90% mortality rate. In the pediatric population, this would equate to a large number of years of life lost, posing a heavy medical and economic burden to society. OBJECTIVE: The purpose of this study was to outline the characteristics and causes of pediatric OHCA (pOHCA) and associations with survival until discharge in patients enrolled in the End Unexplained Cardiac Death Registry. METHODS: A prospective statewide multisource registry identified all pOHCAs cases in patients aged 1-18 years in Victoria, Australia (population 6.5 million), from April 2019 to April 2021. Cases were adjudicated using ambulance, hospital, and forensic records; clinic assessments; and interviews of survivors and family members. RESULTS: The analysis included 106 cases after adjudication (62, 58.5% male), 45 (42.5%) of which were due to cardiac causes of OHCA, with unascertained (n = 33 [31.1%]) being the most common cardiac cause reported. Respiratory events (n = 28 [26.4%]) were the most common noncardiac cause of pOHCA. Noncardiac causes were more likely to present with asystole or pulseless electrical activity (P = .007). The overall survival to hospital discharge rate was 11.3% and associated with increasing age, witnessed cardiac arrest, and initial ventricular arrhythmias (P < .05). CONCLUSION: The incidence of pOHCA in the study population was 3.69 per 100,000 child-years. In contrast to young adults with OHCA, the most common etiology was noncardiac in pediatric patients. Prognostic factors associated with survival to discharge included increasing age, witnessed arrest, and initial ventricular arrhythmias. Rates of cardiopulmonary resuscitation and defibrillation were suboptimal.

Compensation for radiotherapy treatment interruptions due to a cyberattack: An isoeffective DVH-based dose compensation decision tool.

Unscheduled interruptions to radiotherapy treatments lead to decreased tumor control probability (TCP). Rapid cell repopulation in the tumor increases due to the absence of radiation dose, resulting in the loss of TCP. Compensation for this loss is required to prevent or reduce an extension of the patient's overall treatment time and regain the original TCP. The cyberattack on the Irish public health service in May 2021 prevented radiotherapy treatment delivery resulting in treatment interruptions of up to 12 days. Current standards for treatment gap calculations are performed using the Royal College of Radiologists (RCR) methodology, using a point-dose for planning target volume (PTV) and the organs at risk (OAR). An in-house tool, named EQD2 VH, was created in Python to perform treatment gap calculations using the dose-volume histogram (DVH) information in DICOM data extracted from commercial treatment planning system plans. The physical dose in each dose bin was converted into equivalent dose in 2-Gy fractions (EQD2 ), accounting for tumor cell repopulation. This EQD2 -based DVH provides a 2D representation of the impact of treatment gap compensation strategies on both PTV and OAR dose distributions compared to the intended prescribed treatment plan. This additional information can aid clinicians' choice of compensation options. EQD2 VH was evaluated using five high-priority patients experiencing a treatment interruption when the cyberattack occurred. Compensation plans were created using the RCR methodology to evaluate EQD2 VH as a decision-making tool. The EQD2 VH method demonstrated that the comparison of compensated treatment plans alongside the original intended treatment plans using isoeffective DVH analysis can be achieved. It enabled a visual and quantitative comparison between treatment plan options and provided an individual analysis of each structure in a patient's plan. It demonstrated potential to be a useful decision-making tool for finding a balance between optimizing dose to PTV while protecting OARs.

Telehealth in Australian cardiology: insight into factors predicting the use of telephone versus video during the COVID-19 pandemic.

BACKGROUND: The use of telehealth has increased dramatically in Australia in 2020 as a pragmatic response to the COVID-19 pandemic; however, differences between telehealth modalities have not been established. AIM: To identify characteristics contributing to choosing telephone (TP) versus video consultation (VC) and assess patient outcomes between telehealth modalities. METHODS: We conducted an observational study of cardiology outpatients at a tertiary hospital with appointments from 17 March 2020 to 12 August 2020. Demographic variables and appointment modality were compared between each group. Outcomes assessed were mortality, emergency department (ED) presentations and cross over between appointment modalities. RESULTS: There were 1754 telemedicine encounters with 1188 patients seen by TP and 327 patients by VC. Consulting volume increased from previous years. Cardiac mortality was low (0.3%). There were no differences in mortality or ED presentations between telehealth modalities. Patients choosing TP over VC were older (P < 0.001), more likely to be female (P = 0.005), non-English-speaking (P = 0.041), living in metropolitan Melbourne (P < 0.0001), undertaking a first appointment (P = 0.002) and seeing particular cardiologists (P < 0.001). VC patients were more likely to have early review (P = 0.015), and this was likely to be TP (P < 0.0001). TP patients were more likely to follow up in person (P < 0.0001). CONCLUSION: During COVID-19, we increased consultation volumes without adverse patient outcomes. We identified factors influencing the choice of telemedicine modality which did not translate into differences in mortality or ED presentations. Telemedicine is a growing platform with an important role of facilitating access to healthcare for diverse patient groups.

End-to-end dosimetric audit: A novel procedure developed for Irish HDR brachytherapy centres.

PURPOSE: A dosimetric audit of Ir-192 high dose rate (HDR) brachytherapy remote after-loading units was carried out in 2019. All six brachytherapy departments on the island of Ireland participated in an end-to-end test and in a review of local HDR dosimetry procedures. MATERIALS AND METHODS: A 3D-printed customised phantom was created to position the following detectors at known distances from the HDR source: a Farmer ionization chamber, GafChromic film and thermoluminescent dosimeters (TLDs). Dedicated HDR applicator needles were used to position an Ir-192 source at 2 cm distance from these detectors. The end-to-end dosimetry audit pathway was performed at each host site and included the stages of imaging, applicator reconstruction, treatment planning and delivery. Deviations between planned and measured dose distributions were quantified using gamma analysis methods. Local procedures were also discussed between auditors and hosts. RESULTS: The mean difference between Reference Air Kerma Rate (RAKR) measured during the audit and RAKR specified by the vendor source certificate was 1.3%. The results of end-to-end tests showed a mean difference between calculated and measured dose of 2.5% with TLDs and less than 0.5% with Farmer chamber measurements. GafChromic films showed a mean gamma passing rates of >95% for plastic and metal applicators with 2%/1 mm global tolerance criteria. CONCLUSIONS: The results of this audit indicate dosimetric consistency between centres. The 'end to end' dosimetry audit methodology for HDR brachytherapy has been successfully implemented in a multicentre environment, which included different models of Ir-192 sources and different treatment planning systems. The ability to create a 3D-printed water-equivalent phantom customised to accurately position all three detector types simultaneously at controlled distances from the Ir-192 source under evaluation gives good reproducibility for end-to-end methodology.

Cognitive rehabilitation in the elderly: effects on strategic behavior in relation to goal management.

Executive functions are highly sensitive to the effects of aging and other conditions affecting frontal lobe function. Yet there are few validated interventions specifically designed to address executive functions, and, to our knowledge, none validated in a healthy aging sample. As part of a large-scale cognitive rehabilitation randomized trial in 49 healthy older adults, a modified Goal Management Training program was included to address the real-life deficits caused by executive dysfunction. This program emphasized periodic suspension of ongoing activity to establish goal hierarchies and monitor behavioral output. Tabletop simulated real-life tasks (SRLTs) were developed to measure the processes targeted by this intervention. Participants were randomized to two groups, one of which received the intervention immediately and the other of which was wait-listed prior to rehabilitation. Results indicated improvements in SRLT performance and self-rated executive deficits coinciding with the training in both groups. These gains were maintained at long-term follow-up. Future research will assess the specificity of these effects in patient groups.