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result(s) for
"Hariharan Raju"
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Association of diet with atrial fibrillation: villain or sidekick
2023
Post hoc analysis of the recent PREDIMED (Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts) randomised trial showed that a Mediterranean diet supplemented with olive oil reduced incident AF.4 Prior observational data of the arrhythmogenic impacts of a Mediterranean diet have been conflicted. Weight fluctuation is associated with increased risk of recurrent arrhythmia among AF cohorts.1 3 In the Women’s Health Study that prospectively followed up 34 309 women without AF, the risk of incident AF rose by 4.7% per unit increase in BMI, and transition between categories of overweight further increased incident AF risk.7 However, high-quality clinical studies have highlighted the critical role of weight loss in ameliorating AF risk by demonstrating that weight loss reverses atrial remodelling and AF burden.2 Pathak et al 1 showed that although 10% weight loss improves AF profile, >5% wt fluctuation increases AF burden and reduces rates of freedom from arrhythmia. The American Heart Association (AHA) defines ultraprocessed foods to be ‘highly processed foods that go beyond the incorporation of salt, sweeteners, or fat to include artificial colors and flavors and preservatives that promote shelf stability, preserve texture, and increase palatability’. [...]it serves to underscore the principle that dietary intake and education remain a cornerstone for reduction of AF risk on a population basis and is consistent with current European Society of Cardiology/AHA recommendations that typically exclude ultraprocessed foods.
Journal Article
The yield of postmortem genetic testing in sudden death cases with structural findings at autopsy
by
Papatheodorou, Stathis
,
Till, Janice
,
Cole, Della
in
Autopsy
,
Cardiomyopathy
,
Genetic screening
2020
Sudden cardiac death (SCD) is often associated with structural abnormalities of the heart during autopsy. This study sought to compare the diagnostic yield of postmortem genetic testing in (1) cases with structural findings of uncertain significance at autopsy to (2) cases with autopsy findings diagnostic of cardiomyopathy. We evaluated 57 SCD cases with structural findings at cardiac autopsy. Next-generation sequencing using a panel of 77 primary electrical disorder and cardiomyopathy genes was performed. Pathogenic and likely pathogenic variants were classified using American College of Medical Genetics (ACMG) consensus guidelines. In 29 cases (51%) autopsy findings of uncertain significance were identified whereas in 28 cases (49%) a diagnosis of cardiomyopathy was established. We identified a pathogenic or likely pathogenic variant in 10 cases (18%); in 1 (3%) case with non-specific autopsy findings compared with 9 (32%) cases with autopsy findings diagnostic of cardiomyopathy (p = 0.0054). The yield of genetic testing in SCD cases with autopsy findings consistent with cardiomyopathy is comparable with the yield in cardiomyopathy patients that are alive. Genetic testing in cases with findings of uncertain significance offers lower clinical utility than in cardiomyopathy, with lower yields than detected previously. This highlights the need for stringent evaluation of variant pathogenicity.
Journal Article
Misclassification of cricket in the American College of Cardiology (ACC) Task Force classification of sports
by
La Gerche, Andre
,
Semsarian, Christopher
,
Raju, Hariharan
in
Cardiology
,
Cardiovascular disease
,
Classification
2020
Correspondence to Professor Christopher Semsarian, Faculty of Medicine and Health, University of Sydney, Sydney, NSW 2006, Australia; c.semsarian@centenary.org.au ‘The Mitchell classification’1 is a widely known system published by the American College of Cardiology (ACC) to catalogue sports based on peak static and dynamic components achieved during competition.1 2 Used in the Bethesda guidelines3 and more recent scientific statement from the American Heart Association (AHA) and ACC,2 this helpful framework is widely used for assisting with clinical decisions regarding participation in specific sports by athletes with known cardiovascular disease. Funding This study was funded by an Australian Government Research Training Program, National Health and Medical Research Council (grant number 1059156). Eligibility and disqualification recommendations for competitive athletes with cardiovascular abnormalities: task force 1: classification of sports: dynamic, static, and impact: a scientific statement from the American Heart Association and American College of Cardiology.
Journal Article
Audit of a cardiac screening policy for elite Australian cricketers
2020
To report the compliance and results of an electrocardiogram (ECG) cardiac screening program in male and female elite Australian cricketers.
cross-sectional study.
Elite cricketers were offered screening in accordance with Cricket Australia policy. Players who consented provided a personal and family history, physical examination and resting 12-lead ECG. An audit (1 February 2019) examined all cardiac screening records for male and female players in all Australian Cricket state squads from 16 years upwards. Data extracted from the Cricket Australia database included the number of players who underwent screening; signed waivers opting out; and had follow-up tests. ECGs were re-reviewed according to the International Criteria.
710 players were included in the cohort (mean age 20.4±4.9 years, 62% male). 692 (97.5%) players underwent recommended cardiac screening or signed a waiver opting out (1.1%). 173 (24.4%) players were screened (or signed a waiver) more than once. Follow-up testing was conducted for 59 (6.9%) cases. No players were excluded from sport due to a cardiac problem and no major cardiac incidents occurred to any player in the audit cohort. Review of 830 ECGs showed benign athlete heart changes, including sinus bradycardia (33.5%), left ventricular hypertrophy (16.3%), and incomplete/partial right bundle branch block (8.4%), were common but abnormal screening ECGs were uncommon (2.0%).
An audit of a cardiac screening program in elite Australian cricketers found excellent compliance. A small proportion required follow-up testing and no player was excluded from sport due to a cardiac problem. ECG analysis suggested cricket is a sport of moderate cardiac demands, with benign athlete heart changes common.
Journal Article
The role of genetic testing in diagnosis and care of inherited cardiac conditions in a specialised multidisciplinary clinic
by
Bagnall, Richard D.
,
Nowak, Natalie
,
Ryan, Mark P.
in
Bioinformatics
,
Biomedical and Life Sciences
,
Biomedicine
2022
Background
The diagnostic yield of genetic testing for inherited cardiac diseases is up to 40% and is primarily indicated for screening of at-risk relatives. Here, we evaluate the role of genomics in diagnosis and management among consecutive individuals attending a specialised clinic and identify those with the highest likelihood of having a monogenic disease.
Methods
A retrospective audit of 1697 consecutive, unrelated probands referred to a specialised, multidisciplinary clinic between 2002 and 2020 was performed. A concordant clinical and genetic diagnosis was considered solved. Cases were classified as likely monogenic based on a score comprising a positive family history, young age at onset, and severe phenotype, whereas low-scoring cases were considered to have a likely complex aetiology. The impact of a genetic diagnosis was evaluated.
Results
A total of 888 probands fulfilled the inclusion criteria, and genetic testing identified likely pathogenic or pathogenic (LP/P) variants in 330 individuals (37%) and suspicious variants of uncertain significance (VUS) in 73 (8%). Research-focused efforts identified 46 (5%) variants, missed by conventional genetic testing. Where a variant was identified, this changed or clarified the final diagnosis in a clinically useful way for 51 (13%). The yield of suspicious VUS across ancestry groups ranged from 15 to 20%, compared to only 10% among Europeans. Even when the clinical diagnosis was uncertain, those with the most monogenic disease features had the greatest diagnostic yield from genetic testing.
Conclusions
Research-focused efforts can increase the diagnostic yield by up to 5%. Where a variant is identified, this will have clinical utility beyond family screening in 13%. We demonstrate the value of genomics in reaching an overall diagnosis and highlight inequities based on ancestry. Acknowledging our incomplete understanding of disease phenotypes, we propose a framework for prioritising likely monogenic cases to solve their underlying cause of disease.
Journal Article
Spotlight on sudden arrhythmic death syndrome
2019
Sudden cardiac death (SCD) is defined as death from a cardiac cause within 1 hr of symptom onset or, if unwitnessed, in a person last seen well within 24 hrs. Sudden arrhythmic death syndrome (SADS) describes cases of SCD with no abnormalities found on expert autopsy attributable as the cause of death. The epidemiology of these conditions has been challenging to study as definitions have changed over time; however, it is apparent that the incidence of SCD increases with age whilst SADS decreases as coronary artery disease becomes more prevalent. Accurate reporting of truly negative autopsies of SCDs has been assisted by guidelines from governing bodies such as The Association for European Cardiovascular Pathology, allowing identification of SADS cases. Primary arrhythmic cardiac conditions like ong QT syndrome, Brugada syndrome and catecholaminergic polymorphic ventricular tachycardia are the predominant etiologies of SADS. When the decedent did not have a known phenotype for these conditions, clinical evaluation using screening tests like echocardiogram, resting and stress electrocardiograms and holter monitoring, followed by specialized testing when appropriate such as cardiac magnetic resonance and pharmacological provocation testing of surviving family members becomes crucial in potentially identifying the cause and guide targeted genetic testing. Although advancement in gene analysis such as next-generation sequencing has also allowed the application of “molecular autopsy” to identify pathogenic variants to establish the cause of death and enable cascade testing and risk stratification of family members, many of the genetic variants identified through this method have been classified as non-pathogenic since the establishment of standards and guidelines by the American College of Medical Genetics. Whilst majority of cases of SADS are still unexplained, there is increasing awareness and understanding of this syndrome allowing appropriate identification of surviving family members at risk and implementation of measures to prevent further premature death.
Journal Article
Next-generation sequencing using microfluidic PCR enrichment for molecular autopsy
2019
Background
We aimed to determine the mutation yield and clinical applicability of “molecular autopsy” following sudden arrhythmic death syndrome (SADS) by validating and utilizing low-cost high-throughput technologies: Fluidigm Access Array PCR-enrichment with Illumina HiSeq 2000 next generation sequencing (NGS).
Methods
We validated and optimized the NGS platform with a subset of 46 patients by comparison with Sanger sequencing of coding exons of major arrhythmia risk-genes (
KCNQ1
,
KCNH2
,
SCN5A
,
KCNE1
,
KCNE2
,
RYR2
). A combined large multi-ethnic international SADS cohort was sequenced utilizing the NGS platform to determine overall molecular yield; rare variants identified by NGS were subsequently reconfirmed by Sanger sequencing.
Results
The NGS platform demonstrated 100% sensitivity for pathogenic variants as well as 87.20% sensitivity and 99.99% specificity for all substitutions (optimization subset,
n
= 46). The positive predictive value (PPV) for NGS for rare substitutions was 16.0% (27 confirmed rare variants of 169 positive NGS calls in 151 additional cases). The overall molecular yield in 197 multi-ethnic SADS cases (mean age 22.6 ± 14.4 years, 68% male) was 5.1% (95% confidence interval 2.0–8.1%), representing 10 cases carrying pathogenic or likely pathogenic risk-mutations.
Conclusions
Molecular autopsy with Fluidigm Access Array and Illumina HiSeq NGS utilizing a selected panel of LQTS/BrS and CPVT risk-genes offers moderate diagnostic yield, albeit requiring confirmatory Sanger-sequencing of mutational variants.
Journal Article
Optimizing Distribution System Resilience in Extreme Weather Using Prosumer-Centric Microgrids with Integrated Distributed Energy Resources and Battery Electric Vehicles
by
Prabaharan, Natarajan
,
Thirumalai, Muthusamy
,
Hariharan, Raju
in
Alternative energy sources
,
Analysis
,
Automobiles, Electric
2024
Electric power networks face vulnerabilities from various hazards, including extreme weather and natural disasters, resulting in prolonged outages and service disruptions. This paper proposes prosumer-centric networked electrical microgrids as a solution. EMGs integrate DERs, like SPV panels, WTs, BESSs, and BEVs, to form autonomous microgrids capable of operating independently during grid disruptions. The SMA was used to identify the appropriate allocation of DERs and BEVs to improve the resilience of the system. Prosumers, acting as both producers and consumers, play a crucial role by generating and sharing electricity within the microgrid. BEVs act as mobile energy storage units during emergencies. Load management and demand response strategies prioritize the energy needs for essential facilities, ensuring uninterrupted operation during adverse weather. Robust communication and control systems improve the emergency coordination and response. The resilience analysis focused on two case studies: moderate and severe damage, both under varying weather conditions. Simulations and experiments assessed the microgrid performance with different levels of DERs and demand. By testing on the IEEE 69-bus RDS, evaluated the EMGs’ strengths and limitations, demonstrating their potential to enhance distribution grid resilience against natural disasters.
Journal Article
Assessment of the QT Interval in Athletes: Red Flags and Pitfalls
2018
Purpose of review
Pre-participation athlete screening has led to the referral of asymptomatic athletes with a prolonged QT interval warranting their evaluation for long QT syndrome (LQTS). Establishing a diagnosis of LQTS can be difficult, particularly in asymptomatic athletes presenting with a prolonged QTc < 500 ms. This review examines the evaluatory pathway to ascertain the common pitfalls leading to mis- or overdiagnosis. We discuss the advanced ECG-based tools and consider their application in the diagnostic process.
Recent findings
Critical analysis of the ECG, symptom, and pedigree analysis has established value but relies on experienced interpretation. Protocolisation of the former has effectively reduced error. Exercise recovery ECG testing has demonstrated diagnostic value and provocation testing, reliant on QT hysteresis in LQTS, have shown reasonable sensitivity. Although it is becoming more established in experienced centres, its diagnostic value relies on effective risk stratification and subject selection. LQTS is a rare condition and the precision of any available test is greatly diluted if pre-test probability is low.
Summary
Clinical and familial evaluation and exercise ECG testing are the foundation of the evaluatory process following referral. Adjunctive tests may have high sensitivity for LQTS but rely on high pre-test probability. Several pitfalls have been identified that can lead to misdiagnosis and thus informed evaluation at an experienced specialist centre is appropriate.
Journal Article