Applying Artificial Intelligence for Phenotyping of Inherited Arrhythmia Syndromes

Inherited arrhythmia disorders account for a significant proportion of sudden cardiac death, particularly among young individuals. Recent advances in our understanding of these syndromes have improved patient diagnosis and care, yet certain clinical gaps remain, particularly within case ascertainment, access to genetic testing and risk stratification. Artificial intelligence (AI), specifically machine learning and its subset deep learning, present promising solutions to these challenges. The capacity of AI to process vast amounts of patient data and identify disease patterns differentiates them from traditional methods, which are time and resource intensive. To date, AI models have demonstrated immense potential in condition detection (including asymptomatic/concealed disease) and genotype and phenotype identification, exceeding expert cardiologists in these tasks. Additionally, they have exhibited applicability for general population screening, improving case ascertainment in a set of conditions that are often asymptomatic such as left ventricular dysfunction. Third, models have displayed ability to improve testing protocols, as through model identification of disease and genotype, specific clinical testing (e.g. drug challenges or further diagnostic imaging) can be avoided, reducing health care expenses, speeding diagnosis, and possibly allowing for more incremental or targeted genetic testing approaches. These significant benefits warrant continued investigation of the field, particularly regarding the development and implementation of clinically applicable screening tools. This review summarizes key developments in the field, including studies in Long QT Syndrome, Brugada Syndrome, Hypertrophic Cardiomyopathy, and Arrhythmogenic Cardiomyopathies, and provides direction for effective future AI implementation in clinical practice.

Deep Learning-Augmented ECG Analysis for Screening and Genotype Prediction of Congenital Long QT Syndrome

Importance

Congenital long QT syndrome (LQTS) is associated with syncope, ventricular arrhythmias, and sudden death. Half of patients with LQTS have a normal or borderline-normal QT interval despite LQTS often being detected by QT prolongation on resting electrocardiography (ECG).

Objective

To develop a deep learning-based neural network for identification of LQTS and differentiation of genotypes (LQTS1 and LQTS2) using 12-lead ECG.

Design, Setting, and Participants

This diagnostic accuracy study used ECGs from patients with suspected inherited arrhythmia enrolled in the Hearts in Rhythm Organization Registry (HiRO) from August 2012 to December 2021. The internal dataset was derived at 2 sites and an external validation dataset at 4 sites within the HiRO Registry; an additional cross-sectional validation dataset was from the Montreal Heart Institute. The cohort with LQTS included probands and relatives with pathogenic or likely pathogenic variants in KCNQ1 or KCNH2 genes with normal or prolonged corrected QT (QTc) intervals.

Exposures

Convolutional neural network (CNN) discrimination between LQTS1, LQTS2, and negative genetic test results.

Main Outcomes and Measures

The main outcomes were area under the curve (AUC), F1 scores, and sensitivity for detecting LQTS and differentiating genotypes using a CNN method compared with QTc-based detection.

Results

A total of 4521 ECGs from 990 patients (mean [SD] age, 42 [18] years; 589 [59.5%] female) were analyzed. External validation within the national registry (101 patients) demonstrated the CNN's high diagnostic capacity for LQTS detection (AUC, 0.93; 95% CI, 0.89-0.96) and genotype differentiation (AUC, 0.91; 95% CI, 0.86-0.96). This surpassed expert-measured QTc intervals in detecting LQTS (F1 score, 0.84 [95% CI, 0.78-0.90] vs 0.22 [95% CI, 0.13-0.31]; sensitivity, 0.90 [95% CI, 0.86-0.94] vs 0.36 [95% CI, 0.23-0.47]), including in patients with normal or borderline QTc intervals (F1 score, 0.70 [95% CI, 0.40-1.00]; sensitivity, 0.78 [95% CI, 0.53-0.95]). In further validation in a cross-sectional cohort (406 patients) of high-risk patients and genotype-negative controls, the CNN detected LQTS with an AUC of 0.81 (95% CI, 0.80-0.85), which was better than QTc interval-based detection (AUC, 0.74; 95% CI, 0.69-0.78).

Conclusions and Relevance

The deep learning model improved detection of congenital LQTS from resting ECGs and allowed for differentiation between the 2 most common genetic subtypes. Broader validation over an unselected general population may support application of this model to patients with suspected LQTS.

Implantable cardioverter defibrillator use in arrhythmogenic right ventricular cardiomyopathy in North America and Europe

BACKGROUND AND AIMS

Implantable cardioverter-defibrillators (ICDs) are critical for preventing sudden cardiac death (SCD) in arrhythmogenic right ventricular cardiomyopathy (ARVC). This study aims to identify cross-continental differences in utilization of primary prevention ICDs and survival free from sustained ventricular arrhythmia (VA) in ARVC.

METHODS

This was a retrospective analysis of ARVC patients without prior VA enrolled in clinical registries from 11 countries throughout Europe and North America. Patients were classified according to whether they received treatment in North America or Europe and were further stratified by baseline predicted VA risk into low- (<10%/5 years), intermediate- (10%-25%/5 years), and high-risk (>25%/5 years) groups. Differences in ICD implantation and survival free from sustained VA events (including appropriate ICD therapy) were assessed.

RESULTS

One thousand ninety-eight patients were followed for a median of 5.1 years; 554 (50.5%) received a primary prevention ICD, and 286 (26.0%) experienced a first VA event. After adjusting for baseline risk factors, North Americans were more than three times as likely to receive ICDs {hazard ratio (HR) 3.1 [95% confidence interval (CI) 2.5, 3.8]} but had only mildly increased risk for incident sustained VA [HR 1.4 (95% CI 1.1, 1.8)]. North Americans without ICDs were at higher risk for incident sustained VA [HR 2.1 (95% CI 1.3, 3.4)] than Europeans.

CONCLUSIONS

North American ARVC patients were substantially more likely than Europeans to receive primary prevention ICDs across all arrhythmic risk strata. A lower rate of ICD implantation in Europe was not associated with a higher rate of VA events in those without ICDs.

Patient experiences of implantable cardiac monitoring in hypertrophic cardiomyopathy: an exploratory study

AIMS

Hypertrophic cardiomyopathy (HCM) is the most common inherited heart disease. Insertable cardiac monitors (ICMs) are increasingly used in this population to provide closer monitoring, with the potential for notification systems. However, little is known regarding the psychological impact this information may have on patients. The Abbott Confirm Rx™ ICM has the capability of connecting to the patient's smartphone to enable active participation in their care, as well as two-way communication between the patient and their care providers. This study aimed to explore individuals' experiences of having a smartphone-enabled ICM to monitor for arrhythmias in HCM.

METHODS AND RESULTS

Semi-structured interviews were conducted with 10 participants. Utilizing a grounded theory approach, the interview guide was modified based on emerging themes throughout the study. Reflexive thematic analysis was applied to categorize interview data into codes and overacting themes, with each interview independently coded by two study members. Analysis revealed three key themes: (i) psychological impact, (ii) educational needs, and (iii) technology expectations. Participants reported that receiving feedback from ICM transmissions resulted in improved symptom clarity, providing reassurance, and aiding implantable cardioverter defibrillator decision-making. Some participants reported uncertainty regarding when to send manual transmissions. Lastly, participants reported the app interface did not meet expectations with regard to the amount of data available for patients.

CONCLUSION

Overall, utilizing a smartphone app to facilitate two-way communication of ICM transmissions was well accepted. Future directions include addressing gaps in educational needs and improvements in the patient interface with increased access to data.

Provocation testing in congenital long QT syndrome: A practical guide

Congenital long QT syndrome (LQTS) is a hereditary cardiac channelopathy with an estimated prevalence of 1 in 2500. A prolonged resting QT interval corrected for heart rate (QTc interval) remains a key diagnostic component; however, the QTc value may be normal in up to 40% of patients with genotype-positive LQTS and borderline in a further 30%. Provocation of QTc prolongation and T-wave changes may be pivotal to unmasking the diagnosis and useful in predicting genotype. LQTS provocation testing involves assessment of repolarization during and after exercise, in response to changes in heart rate or autonomic tone, with patients with LQTS exhibiting a maladaptive repolarization response. We review the utility and strengths and limitations of 4 forms of provocation testing-stand-up test, exercise stress test, epinephrine challenge, and mental stress test-in diagnosing LQTS and provide some practical guidance for performing provocation testing. Ultimately, exercise testing, when feasible, is the most useful form of provocation testing when considering diagnostic sensitivity and specificity.

Graded Quasiperiodic Metamaterials Perform Fractal Rainbow Trapping

The rainbow trapping phenomenon of graded metamaterials can be combined with the fractal spectra of quasiperiodic waveguides to give a metamaterial that performs fractal rainbow trapping. This is achieved through a graded cut-and-project algorithm that yields a geometry for which the effective projection angle is graded along its length. As a result, the fractal structure of local band gaps varies with position, leading to broadband "fractal" rainbow trapping. We demonstrate this principle by designing an acoustic waveguide, which is characterised using theory, simulation and experiments.

Investigating blood alcohol concentrations in injury- related deaths before and during the COVID-19 national lockdown in Western Cape Province, South Africa: A cross-sectional retrospective review

BACKGROUND

Alcohol is a significant contributor to injury-related morbidity and mortality in South Africa (SA). During the COVID-19global pandemic, restrictions to movement and to legal access to alcohol (i.e. ethanol) were introduced in SA.

OBJECTIVES

To investigate the effect of alcohol bans during the COVID-19 lockdown periods on injury-related mortality and blood alcoholconcentrations (BACs) in these deaths.

METHODS

A retrospective, cross-sectional analysis of injury-related deaths in Western Cape Province (WC), SA, between 1 January 2019 and31 December 2020 was conducted. Cases where BAC testing was performed were further examined according to the periods of lockdownand alcohol restrictions.

RESULTS

A total of 16 027 injury-related cases were admitted to Forensic Pathology Service mortuaries in the WC over the 2-year period. Anaverage decrease of 15.7% injury-related deaths in 2020 compared with 2019 was noted, as well as a 47.7% decrease in injury-related deathsduring hard lockdown (April - May 2020) compared with the same period in 2019. In the injury-related deaths, 12 077 (75.4%) had bloodspecimens collected for BAC testing. In 5 078 (42.0%) of submitted cases, a positive BAC (≥0.01 g/100 mL) was reported. No significantdifference was observed in the mean positive BAC between 2019 and 2020. However, in April and May 2020, the mean BAC observed(0.13 g/100 mL) was less than that in 2019 (0.18 g/100 mL). A high number of positive BACs in the 12- 17-year age group (23.4%) was observed.

CONCLUSION

There was a clear decrease in injury-related deaths in the WC during the COVID-19-related lockdown periods, whichcoincided with the alcohol ban and restriction of movement, and an increase following relaxation of restrictions on alcohol sales andmovement. The data illustrate that mean BACs were similar between all periods of alcohol restriction compared with 2019, apart from hardlockdown in April - May 2020. This coincided with a smaller mortuary intake during the level 5 and 4 lockdown periods.

Investigating blood alcohol concentrations in injury-related deaths before and during the COVID-19 National lockdown in Western Cape, South Africa: A cross-sectional retrospective review

BACKGROUND

Alcohol is a significant contributor to injury-related morbidity and mortality in South Africa (SA).  During the COVID-19 global pandemic, restrictions to movement and to the legal access of alcohol* were introduced in SA.  This study aimed to investigate the effect of alcohol bans during the COVID-19 lockdown periods on injury-related mortality and the blood alcohol concentrations (BAC) in these deaths.

METHODS

A retrospective, cross-sectional analysis of injury-related deaths in Western Cape (WC) province, SA, between 1 January 2019 to 31 December 2020 was conducted. Cases where BAC testing was performed were further examined according to the periods of lockdown (AL5-1) and alcohol restrictions.

RESULTS

A total of 16,027 injury-related cases were admitted to Forensic Pathology Service mortuaries in the WC over the two-year period.  An average decrease of 15.7% injury-related deaths in 2020 compared to 2019 was noted, as well as a 47.7% decrease in injury-related deaths during hard lockdown (April -May 2020) compared to the same period in 2019. In the injury-related deaths, 12,077 (75.4%) had blood specimens collected for BAC testing. In 5,078 (42.0%) of submitted cases, a positive BAC (≥0.01g/100 mL) was reported. No significant difference was observed in the mean positive BAC between 2019 and 2020, however in April and May 2020, the mean BACs observed (0.13 g/100 mL) was less than that in 2019 (0.18 g/100 mL). A high number of positive BACs in the 12-17-year age group (±23.4%) was observed.

CONCLUSION

There was a clear decrease in injury-related deaths in the WC during the COVID-19-related lockdown periods that coincided with the alcohol ban and restriction of movement and an increase following relaxation of restrictions on alcohol sales and movement. The data illustrated that mean BACs were similar between all periods of alcohol restriction compared to 2019, apart from hard lockdown in April-May, 2020.  This coincided with a smaller mortuary intake during the level 5 and 4 lockdown periods.   Keywords: Alcohol; blood alcohol concentration; COVID-19; injury; lockdown; South Africa; violent death; Western Cape   * Alcohol refers to ethanol.

Perceived self-efficacy and empowerment in patients at increased risk of sudden cardiac arrest

Background

The role of multidisciplinary clinics for psychosocial care is increasingly recognized for those living with inherited cardiac conditions (ICC). In Canada, access to healthcare providers differ between clinics. Little is known about the relationship between access to specialty care and a patient's ability to cope with, and manage their condition.

Methods

We leveraged the Hearts in Rhythm Organization (HiRO) to conduct a cross-sectional, community-based survey of individuals with ICC and their family members. We aimed to describe access to services, and explore the relationships between participants' characteristics, cardiac history and self-reported health status and self-efficacy (GSE: General Self-Efficacy Scale) and empowerment (GCOS-24: Genetic Counseling Outcome Scale).

Results

We collected 235 responses from Canadian participants in 10 provinces and territories. Overall, 63% of participants reported involvement of a genetic counsellor in their care. Access to genetic testing was associated with greater empowerment [mean GCOS-24: 121.14 (SD = 20.53) vs. 105.68 (SD = 21.69); p = 0.004]. Uncertain genetic test results were associated with lower perceived self-efficacy (mean GSE: uncertain = 28.85 vs. positive = 33.16, negative = 34.13; p = 0.01). Low global mental health scores correlated with both lower perceived self-efficacy and empowerment scores, with only 11% of affected participants reporting involvement of psychology services in their care.

Conclusion

Differences in resource accessibility, clinical history and self-reported health status impact the perceived self-efficacy and empowerment of patients with ICC. Future research evaluating interventions to improve patient outcomes is recommended.

Antimicrobial use in animals: a journey towards integrated surveillance

In 2015, the World Organisation for Animal Health (WOAH, founded as OIE) initiated the annual collection of data on antimicrobials intended for use in animals using a Microsoft Excel questionnaire. In 2022, WOAH initiated the migration to a customised interactive online system: ANIMUSE Global Database. This system enables national Veterinary Services not only to monitor and report data more easily and more accurately, but also to visualise, analyse and use data for surveillance purposes to their own benefit in the implementation of national action plans on antimicrobial resistance. This journey started seven years ago, with progressive improvements in the way data are collected, analysed and reported and continuous adaptations to overcome various challenges encountered (e.g. data confidentiality, training of civil servants, calculation of active ingredients, standardisation to enable fair comparisons and trend analyses, and data interoperability). Technical developments have been key in the success of this endeavour. However, it is important not to underestimate the importance of the human element: to listen to WOAH Members and their needs, and to exchange to solve issues, adapt tools, and gain and maintain trust. The journey is not over yet, and more developments are foreseen, such as to complement current data sources with data collected directly at the farm level; strengthen interoperability and integrated analysis with cross-sectoral databases; and facilitate institutionalisation of data collection and systematic use in monitoring, evaluation, lesson learning, reporting and, eventually, surveillance of antimicrobial use and antimicrobial resistance when implementing and updating national action plans. This paper describes how all these challenges were overcome and how future challenges will be addressed.

Management of Inherited Arrhythmia Syndromes: a HiRO Consensus Handbook on Process of Care

Inherited arrhythmia syndromes are rare genetic conditions that predispose seemingly healthy individuals to sudden cardiac arrest and death. The Hearts in Rhythm Organization is a multidisciplinary Canadian network of clinicians, researchers, patients, and families that aims to improve care for patients and families with inherited cardiac conditions, focused on those that confer predisposition to arrhythmia and sudden cardiac arrest and/or death. The field is rapidly evolving as research discoveries increase. A streamlined, practical guide for providers to diagnose and follow pediatric and adult patients with inherited cardiac conditions represents a useful tool to improve health system utilization, clinical management, and research related to these conditions. This review provides consensus care pathways for 7 conditions, including the 4 most common inherited cardiac conditions that confer predisposition to arrhythmia, with scenarios to guide investigation, diagnosis, risk stratification, and management. These conditions include Brugada syndrome, long QT syndrome, arrhythmogenic right ventricular cardiomyopathy and related arrhythmogenic cardiomyopathies, and catecholaminergic polymorphic ventricular tachycardia. In addition, an approach to investigating and managing sudden cardiac arrest, sudden unexpected death, and first-degree family members of affected individuals is provided. Referral to specialized cardiogenetic clinics should be considered in most cases. The intention of this review is to offer a framework for the process of care that is useful for both experts and nonexperts, and related allied disciplines such as hospital management, diagnostic services, coroners, and pathologists, in order to provide high-quality, multidisciplinary, standardized care.

Incremental value of the signal-averaged ECG for diagnosing arrhythmogenic cardiomyopathy

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is currently diagnosed using a combination of clinical features, imaging, electrocardiography, and genetic investigations. An abnormal signal-averaged electrocardiogram (SAECG) is defined as a minor diagnostic criterion by the 2010 Task Force Criteria, but doubts remain about the value of this investigation.

OBJECTIVE

We evaluated the utility of the SAECG in diagnosing ARVC using the Canadian Arrhythmogenic Right Ventricular Cardiomyopathy Registry, a population representative registry of probands with ARVC and relatives, less influenced by referral bias.

METHODS

Probands with ARVC and family members from the Canadian Arrhythmogenic Right Ventricular Cardiomyopathy Registry underwent phenotype review. SAECG parameters were compared individually and in combination between those with varying degrees of ARVC severity and healthy controls (family members of probands with ARVC and unexplained sudden death, free of evidence of cardiac disease).

RESULTS

A total of 196 patients with ARVC and 205 controls were included (mean age 44 ± 15 years; 186 of 401 men [46%]). SAECG abnormalities were seen in 83 of 205 controls (40%), 33 of 68 patients with ARVC and mild disease (51%), and 31 of 42 with severe disease (74%). The SAECG associated strongly with imaging abnormalities (major: odds ratio 3.0, 95% confidence interval 1.3-6.9; minor: odds ratio 3.5, 95% confidence interval 0.7-16.5) but not with other aspects of phenotype. Patients carrying pathogenic variants but with minimal phenotype had similar SAECGs to healthy controls (filtered QRS duration 111.2 ± 11.2 ms vs 111 ± 7.6 ms, P = .93; duration of low amplitude signals < 40 μV 32.3 ± 8.9 ms vs 34.2 ± 7.2 ms, P = .32; root mean square of the terminal 40 ms of the filtered QRS complex 43.1 ± 25.2 ms vs 38.2 ± 20.2 ms, P = .38).

CONCLUSION

The SAECG appears to be a surrogate marker for structural abnormalities seen on imaging in those with ARVC. Great caution is required in interpreting SAECG findings in those without other corroborating evidence of an ARVC phenotype.

Sex Differences and Utility of Treadmill Testing in Long‐QT Syndrome

Background

Diagnosis of congenital long‐QT syndrome (LQTS) is complicated by phenotypic ambiguity, with a frequent normal‐to‐borderline resting QT interval. A 3‐step algorithm based on exercise response of the corrected QT interval (QTc) was previously developed to diagnose patients with LQTS and predict subtype. This study evaluated the 3‐step algorithm in a population that is more representative of the general population with LQTS with milder phenotypes and establishes sex‐specific cutoffs beyond the resting QTc.

Methods and Results

We identified 208 LQTS likely pathogenic or pathogenic KCNQ1 or KCNH2 variant carriers in the Canadian NLQTS (National Long‐QT Syndrome) Registry and 215 unaffected controls from the HiRO (Hearts in Rhythm Organization) Registry. Exercise treadmill tests were analyzed across the 5 stages of the Bruce protocol. The predictive value of exercise ECG characteristics was analyzed using receiver operating characteristic curve analysis to identify optimal cutoff values. A total of 78% of male carriers and 74% of female carriers had a resting QTc value in the normal‐to‐borderline range. The 4‐minute recovery QTc demonstrated the best predictive value for carrier status in both sexes, with better LQTS ascertainment in female patients (area under the curve, 0.90 versus 0.82), with greater sensitivity and specificity. The optimal cutoff value for the 4‐minute recovery period was 440 milliseconds for male patients and 450 milliseconds for female patients. The 1‐minute recovery QTc had the best predictive value in female patients for differentiating LQTS1 versus LQTS2 (area under the curve, 0.82), and the peak exercise QTc had a marginally better predictive value in male patients for subtype with (area under the curve, 0.71). The optimal cutoff value for the 1‐minute recovery period was 435 milliseconds for male patients and 455 milliseconds for femal patients.

Conclusions

The 3‐step QT exercise algorithm is a valid tool for the diagnosis of LQTS in a general population with more frequent ambiguity in phenotype. The algorithm is a simple and reliable method for the identification and prediction of the 2 major genotypes of LQTS.

Arrhythmic risk prediction in arrhythmogenic right ventricular cardiomyopathy: external validation of the arrhythmogenic right ventricular cardiomyopathy risk calculator

AIMS

Arrhythmogenic right ventricular cardiomyopathy (ARVC) causes ventricular arrhythmias (VAs) and sudden cardiac death (SCD). In 2019, a risk prediction model that estimates the 5-year risk of incident VAs in ARVC was developed (ARVCrisk.com). This study aimed to externally validate this prediction model in a large international multicentre cohort and to compare its performance with the risk factor approach recommended for implantable cardioverter-defibrillator (ICD) use by published guidelines and expert consensus.

METHODS AND RESULTS

In a retrospective cohort of 429 individuals from 29 centres in North America and Europe, 103 (24%) experienced sustained VA during a median follow-up of 5.02 (2.05-7.90) years following diagnosis of ARVC. External validation yielded good discrimination [C-index of 0.70 (95% confidence interval-CI 0.65-0.75)] and calibration slope of 1.01 (95% CI 0.99-1.03). Compared with the three published consensus-based decision algorithms for ICD use in ARVC (Heart Rhythm Society consensus on arrhythmogenic cardiomyopathy, International Task Force consensus statement on the treatment of ARVC, and American Heart Association guidelines for VA and SCD), the risk calculator performed better with a superior net clinical benefit below risk threshold of 35%.

CONCLUSION

Using a large independent cohort of patients, this study shows that the ARVC risk model provides good prognostic information and outperforms other published decision algorithms for ICD use. These findings support the use of the model to facilitate shared decision making regarding ICD implantation in the primary prevention of SCD in ARVC.

Exploring the contribution of mechano-sensing to cardiomyopathy

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Medical Research Council (MR/V009540/1),

Wellcome Trust (201543/B/16/Z)

British Heart Foundation (FS/12/40/29712).

Hypertrophic cardiomyopathy (HCM) is an inherited cardiac condition associated with diastolic dysfunction and sudden cardiac death. Disease genes for HCM are traditionally coding for proteins involved in force generation. More recently, it has emerged that variants in genes coding for proteins involved in biomechanical stress-signalling can also cause HCM.

One such protein is filamin C, with proposed mechano-sensing functions in the heart. Within the protein, the immunoglobulin-like domain 20 (Ig20) may play a crucial role in mediating binding to muscle specific ligands. While the mechano-sensing functions of filamin C have been investigated well in skeletal muscle, the underlying cardiac disease mechanisms are not completely understood.

Aim

This work attempts to provide insights into the role of filamin C in cardiac mechano-sensing and dissect disease pathways leading to HCM in the presence of the FLNC variants in Ig20.

Methods

Using mass spectrometry, we aimed to provide a detailed analysis of the proteome of mice carrying the filamin C variant, using ventricular tissue samples from 14wk old homozygous mice. Samples were subject to molecular biology technical and underwent subcellular fractionation (n = 6 per genotype) and were investigated by label-free mass spectrometry.

Results

Utilising whole genome sequencing, a heterozygous FLNC missense variant in Ig20 was identified in a three-generation family affected by HCM. Mice carrying this variant recapitulate molecular features of HCM in the homozygous setting. Three proteins (FLNC, MYH7, MYOT) were found to be upregulated in the myofilament-enriched fraction. Up-regulations of key proteins were found to relocalise towards load-baring sites.

Conclusion

Our data indicate that changes in filamin C and its binding partners expression and localisation are involved in the pathogenesis of HCM in this mouse model.

Crucial functions of alpha-actinin 2 in the embryonic heart

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Wellcome Trust; British Heart Foundation

Background/Introduction

Alpha-actinin is an integral protein of the Z-discs in heart and skeletal muscle cells, with important structural and signalling functions.  Missense variants in alpha-actinin can cause inherited conditions, e.g. myopathies and cardiomyopathies. The underlying disease mechanisms are still unknown.

Purpose

In order to study the disease mechanisms of an alpha-actinin missense variant, which is known to cause Hypertrophic Cardiomyopathy in human patients, a mouse model was generated.

Methods

Mice carrying the alpha-actinin missense variant were generated by CRISPR-Cas9 genome editing. The heterozygous adult mice carrying the alpha-actinin variant were characterised by echocardiography and quantitative PCR. Hearts of homozygous embryos were analysed at E15.5 by high-resolution episcopic microscopy (HREM).

Results

Mice carrying a single copy of the missense variant were viable and had normal appearance. Adult heterozygous mice showed no signs of cardiomyopathy on echocardiography. However, mature male mice displayed molecular signs of cardiomyopathy, such as induction of the fetal gene programme at transcript level.

The attempt to generate adult mice homozygous for the variant failed: 9 breeding pairs produced 18 litters with 83 weaned pups, but no homozygous offspring. Embryonic lethality was confirmed and E15.5 was the latest stage homozygous pups were reliably found to be viable. At this timepoint, genotype distribution was within the expected Mendelian ratios.

HREM of the hearts at this stage revealed increased right ventricular chamber size and decreased left atrial size, when compared to wildtype littermates. Membranous ventricular septal defects were observed in 3 out of 8 homozygous hearts. Further these embryos displayed aortic stenosis and dysplasic leaflets of the pulmonary valve.

Conclusions

Heterozygous adult mice only displayed sub-clinical signs of disease. In contrast, the missense variant is embryonic lethal in the homozygous setting and leads to a range of morphological abnormalities in E15.5 hearts. Future work will identify how altered functions of alpha-actinin cause these changes.

OUP accepted manuscript

Aims

Genetic testing is recommended in specific inherited heart diseases but its role remains unclear and it is not currently recommended in unexplained cardiac arrest (UCA). We sought to assess the yield and clinical utility of genetic testing in UCA using whole-exome sequencing (WES).

Methods and results

Survivors of UCA requiring external defibrillation were included from the Cardiac Arrest Survivor with Preserved Ejection fraction Registry. Whole-exome sequencing was performed, followed by assessment of rare variants in previously reported cardiovascular disease genes. A total of 228 UCA survivors (mean age at arrest 39 ± 13 years) were included. The majority were males (66%) and of European ancestry (81%). Following advanced clinical testing at baseline, the likely aetiology of cardiac arrest was determined in 21/228 (9%) cases. Whole-exome sequencing identified a pathogenic or likely pathogenic (P/LP) variant in 23/228 (10%) of UCA survivors overall, increasing the proportion of ‘explained’ cases from 9% only following phenotyping to 18% when combining phenotyping with WES. Notably, 13 (57%) of the 23 P/LP variants identified were located in genes associated with cardiomyopathy, in the absence of a diagnosis of cardiomyopathy at the time of arrest.

Conclusions

Genetic testing identifies a disease-causing variant in 10% of apparent UCA survivors. The majority of disease-causing variants was located in cardiomyopathy-associated genes, highlighting the arrhythmogenic potential of such variants in the absence of an overt cardiomyopathy diagnosis. The present study supports the use of genetic testing including assessment of arrhythmia and cardiomyopathy genes in survivors of UCA.

Return of Results Policies for Genomic Research: Current Practices & The Hearts in Rhythm Organization Approach

Research teams developing biobanks and/or genomic databases must develop policies for the disclosure and reporting of potentially actionable genomic results to research participants. Currently, a broad range of approaches to the return of results exist, with some studies opting for non-disclosure of research results while others follow clinical guidelines for the return of potentially actionable findings from sequencing. In this review, we describe current practices and highlight decisions a research team must make when designing a return of results policy, from informed consent to disclosure practices and clinical validation options. The unique challenges of returning incidental findings in cardiac genes, including reduced penetrance and the lack of clinical screening standards for phenotype-negative individuals are discussed. Lastly, the National Hearts in Rhythm Organization (HiRO) Registry approach is described to provide a rationale for the selective return of field-specific variants to those participating in disease-specific research. Our goal is to provide researchers with a resource when developing a return of results policy tailored for their research program, based on unique factors related to study design, research team composition and availability of clinical resources.

Sex-differences and utility of treadmill testing in identification and genotype prediction in LQTS: a sub-study of the national LQTS registry and Canadian Hearts in Rhythm registry

Background/Purpose

Long-QT (LQT) Syndrome is an inherited heart rhythm condition presenting with QT-prolongation and failure to shorten with exercise, leading to life-threatening cardiac events. The prevalent normal-to-borderline phenotype remains a challenge for diagnosis. A three-step algorithm was developed to predict genotype from phenotypic characteristics with exercise testing. Sex-specific cut offs for determining a prolonged corrected QT value are 470ms for males and 480ms for females, serving as step 1 in the algorithm. The purpose of this study is to validate the algorithm using a national cohort that is more representative of the general LQT population, with a milder phenotype and more frequent ambiguity in phenotype.

Methods

A review of cases in the Canadian National Long-QT Registry, housed in the HiRO Registry was undertaken. Eligible cases from September 2014 to May 2020 were included. Gene-positive patients included 93 probands and 122 first-degree relatives (FDR) with a likely-pathogenic or pathogenic mutation according to ACMG criteria, limited to LQT1/2 subtypes, with 164 and 51 patients, respectively. Controls were composed of 39 gene-negative FDRs. Continuous variables were compared by the Mann-Whitney U test for 2-group comparisons, and Kruskal-Wallis test for multiple group comparisons. The predictive value of exercise ECG characteristics were analysed using ROC analysis and optimal cut-off values for exercise ECG characteristics (supine, standing, peak exercise, 1 and 4-minutes into recovery) were determined for males and females, using a sensitivity of 0.80 for carrier status and 0.75 for subtype.

Results

The 4-minute recovery QTc had the best predictive value for males, with an AUC of 0.86, and a cut-off point of 442ms given a sensitivity of 0.81 and specificity of 0.86. The 4-minute recovery QTc yielded an AUC of 0.79 for females, with a cut-off of 452ms given a sensitivity of 0.81 and specificity of 0.71. The 1-minute recovery QTc had the best predictive value for females, with an AUC of 0.92 and a cut-off point of 424ms given a sensitivity of 0.82 and specificity of 0.94. In prediction of LQT1, the 1-minute recovery QTc yielded the highest AUC for both males and females, at 0.68 and 0.80, respectively. Males had a cut off of 428ms with a sensitivity of 0.75 and specificity of 0.47, while females had a cut off of 451ms given a sensitivity of 0.76 and specificity of 0.75.

Conclusion

The current study demonstrates that exercise testing is a valid approach to diagnosing LQTS, with a differential optimal best measurement in males vs. females. Test performance measured by AUC was generally better at all time points in females compared to males. The algorithm is a reliable and simple method for the identification and prediction of genotype for probands and FDR carriers. The algorithm should be sex-stratified at the second step, with the 4-minute recovery QTc used for males and the 1-minute recovery QTc for females.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Canadian Institute of Health Research

619 Is the Subdivision of Thy3 Nodules Needed? An Audit Reviewing the Management of Thy3 Nodules, and the Associated Malignancy Rates

Introduction

Following the 2014 update to the BAETS thyroid nodule cytology guidance, the management of Thy3 lesions was modified by subdivision into Thy3a and Thy3f categories. Both lesions remain indeterminate but are proposed to have differing risks of malignancy when counselling patents: these risks have been called into question by subsequent data.

Aim

This Audit aimed to review the management of Thy3 (Thy3a and Thy3f) cytological diagnoses, within an NHS Trust, and compare this to the BAET Guidance 2014. Further, malignancy rates for Thy3a and Thy3f cytology were made over the calculated over the time period.

Method

A retrospective Audit looking at 118 patients with a Thy3 cytology identified between 2014 and 2019. Data separated into data pre-2015 and 2015 onwards.

Results

In 2014, 29% of Thy3a nodules were managed in line with 2014 BAETS guidance. This improved to 34% from 2015. Meanwhile, Thy3f diagnoses were managed mostly in favour of the BAETS guidelines – 83% in 2014 and 92% 2015 onwards. The malignancy rates found, amongst all 118 patients, were 17.2% and 14.8% for Thy3f and Thy3a nodules respectively.

Conclusions

At this institution, Thy3 cytological diagnoses, regardless of classification into Thy3a or Thy3f, were largely treated in the same way (by a diagnostic hemi-thyroidectomy). The management of the nodules may reflect a variety of factors, including how comfortable patients and surgeons are when handling uncertainty. With malignancy rates for both Thy3a and Thy3f nodules being much the same, it is not surprising that they are managed in a similar way.

1671 The Effect Of COVID-19 On the Management and Outcome of Neck of Femur Fractures in A District General Hospital - A Comparative Study

Aim

We wanted to see how the virus has impacted the management and outcome of our neck of femur fracture patients during Spring 2020.

Method

We performed a retrospective study of all neck of femur fracture patients presenting to our hospital from 23rd March 2020 (start of official lockdown in UK) until the end of May 2020 and compared them to patients presenting in the same time period in 2019. We recorded patient demographics, COVID-19 swab results, time to surgery, length of stay, transfers between wards, and 30-day mortality rates.

Results

We identified 75 patients in 2020 compared to 88 in 2019. Average length of stay was 11.4 days compared to 14.3 a year earlier. Mean time to surgery was 32.3 hours compared to 31.6 in 2019. The 30-day mortality increased significantly from 5.7% (5/88) in 2019 to 16% (12/75) in 2020 (p &lt; 0.05) From 73 patients tested for COVID-19, 3 had a positive swab. Of these, 2 died. During their admission, 14 patients were transferred to 3 or more wards; in this group, 30-day mortality was 42.9% (6/14).

Conclusions

There has been a significant increase in 30-day mortality during COVID-19. Despite maintaining our time to surgery and reducing overall length of stay, we saw an increase in mortality, associated with multiple ward transfers rather than a high number of COVID-19 positive swab cases. Changes in pathways and wards configurations led to some patients requiring multiple transfers. This can cause difficulties in coordinated, multidisciplinary care for patients with NOF Fractures.

1085 Equestrian Related Pelvic and Acetabular Fractures – Experience from a Major Trauma Centre in England

Introduction

Equestrianism is enjoyed by three million people in the UK; however, there is a lack of literature on pelvic and acetabular (P&A) injuries incurred through the sport. We aim to describe P&A injuries sustained in equestrian accidents, discuss management, and establish their outcomes.

Method

Data was extracted from a prospectively collected database of referrals to the P&A Service of a Major Trauma Centre (MTC) from 01/01/2016 to 31/12/2020 and cross-referenced with medical records.

Results

60 of the 1,218 P&A referrals were secondary to horse-riding accidents. Mean age 45 (SD 16.59); 46 female; 33 managed non-operatively and 27 managed operatively at the MTC. There was sufficient information for 59 cases to be classified; 46 of the injuries were pelvic fractures (10 anterior-posterior compression; 29 lateral compression; 4 sacral and 3 pubic rami fractures) and 13 were acetabular (2 anterior column; 1 anterior wall; 2 associated both columns; 1 posterior column and posterior wall; 1 posterior wall; 2 T-shaped and 4 transverse fractures). The operative group were managed by examination under anaesthesia (n = 3), open reduction internal fixation (n = 22) or percutaneous fixation (n = 2). Mean hospitalisation was 9.2 days (SD 5.44). 81% were non-weight-bearing post-operatively and mean time to independent mobilisation was 12.6 weeks (SD 7.09). Return-to-riding information was available for 8 patients with a mean of 29.5 weeks (SD 11.55).

Conclusions

Equestrianism can result in significant P&A injuries. Patients should be counselled that they may have a long recovery, a protracted return-to-riding time and some may never return to the sport.

1514 Higher Mortality in Pelvic Acetabular Fractures Is Associated with Lower Body Mass Index

Aim

Fractures of the pelvis and acetabulum can be life-threatening or life changing injuries. Multiple factors can contribute to outcome including age, frailty, and baseline nutritional status. The aim of this study was to identify if low BMI (&lt;18.5) was a predictor of outcome for patients with such injuries in terms of morbidity and mortality.

Method

We retrospectively analysed 1033 patients with pelvic or acetabular fractures referred to a single level 1 major trauma centre over a 4.5-year period (August 2015 - January 2020). Of these patients, 569 were admitted to the centre and included in our analysis. Data was collected on demographics, injury pattern, operative intervention, and complications. Comparison was made between patients that were underweight (BMI&lt;18.5) and patients that were not, for in-hospital and post discharge complications including pulmonary embolus (PE), deep venous thrombosis (DVT), ileus, infection, loss of reduction and mortality at 6 months.

Results

Underweight patients had a statistically significant increase in mortality both in-hospital (p = 0.019) and at 6 months post injury (p = 0.039) when compared to other BMI groups. No statistical significance was found between these BMI groups comparing morbidity: DVT (p = 0.712), PE (p = 0.736) nor ileus (p = 0.149). Covariate analysis showed that a low BMI was associated with 3 times increased in-hospital mortality after correction for age and energy of injury (adjusted OR 3.028, 95% CI 1.059-8.659).

Conclusions

This study suggests increased mortality in patients with pelvic or acetabular fractures who are underweight. Surgeons should consider these findings in initiating appropriate peri-operative optimisation for these patients.

Short-coupled ventricular fibrillation represents a distinct phenotype among latent causes of unexplained cardiac arrest: a report from the CASPER registry

AIMS

The term idiopathic ventricular fibrillation (IVF) describes survivors of unexplained cardiac arrest (UCA) without a specific diagnosis after clinical and genetic testing. Previous reports have described a subset of IVF individuals with ventricular arrhythmia initiated by short-coupled trigger premature ventricular contractions (PVCs) for which the term short-coupled ventricular fibrillation (SCVF) has been proposed. The aim of this article is to establish the phenotype and frequency of SCVF in a large cohort of UCA survivors.

METHODS AND RESULTS

We performed a multicentre study including consecutive UCA survivors from the CASPER registry. Short-coupled ventricular fibrillation was defined as otherwise unexplained ventricular fibrillation initiated by a trigger PVC with a coupling interval of <350 ms. Among 364 UCA survivors, 24/364 (6.6%) met diagnostic criteria for SCVF. The diagnosis of SCVF was obtained in 19/24 (79%) individuals by documented ventricular fibrillation during follow-up. Ventricular arrhythmia was initiated by a mean PVC coupling interval of 274 ± 32 ms. Electrical storm occurred in 21% of SCVF probands but not in any UCA proband (P < 0.001). The median time to recurrent ventricular arrhythmia in SCVF was 31 months. Recurrent ventricular fibrillation resulted in quinidine administration in 12/24 SCVF (50%) with excellent arrhythmia control.

CONCLUSION

Short-coupled ventricular fibrillation is a distinct primary arrhythmia syndrome accounting for at least 6.6% of UCA. As documentation of ventricular fibrillation onset is necessary for the diagnosis, most cases are diagnosed at the time of recurrent arrhythmia, thus the true prevalence of SCVF remains still unknown. Quinidine is effective in SCVF and should be considered as first-line treatment for patients with recurrent episodes.

Variant Reinterpretation in Survivors of Cardiac Arrest With Preserved Ejection Fraction (the Cardiac Arrest Survivors With Preserved Ejection Fraction Registry) by Clinicians and Clinical Commercial Laboratories

BACKGROUND

Following an unexplained cardiac arrest, clinical genetic testing is increasingly becoming standard of care. Periodic review of variant classification is required, as reinterpretation can change the diagnosis, prognosis, and management of patients and their relatives.

METHODS

This study aimed to develop and validate a standardized algorithm to facilitate clinical application of the 2015 American College of Medical Genetics and Association for Molecular Pathology guidelines for the interpretation of genetic variants. The algorithm was applied to genetic results in the Cardiac Arrest Survivors With Preserved Ejection Fraction Registry, to assess the rate of variant reclassification over time. Variant classifications were then compared with the classifications of 2 commercial laboratories to determine the rate and identify sources of variant interpretation discordance.

RESULTS

Thirty-one percent of participants (40 of 131) had at least 1 genetic variant with a clinically significant reclassification over time. Variants of uncertain significance were more likely to be downgraded (73%) to benign than upgraded to pathogenic (27%; P=0.03). For the second part of the study, 50% (70 of 139) of variants had discrepant interpretations (excluding benign variants), provided by at least 1 team.

CONCLUSIONS

Periodic review of genetic variant classification is a key component of follow-up care given rapidly changing information in the field. There is potential for clinical care gaps with discrepant variant interpretations, based on the interpretation and application of current guidelines. The development of gene- and disease-specific guidelines and algorithms may provide an opportunity to further standardize variant interpretation reporting in the future. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT00292032.

Patch monitors for arrhythmia monitoring in patients for suspected inherited arrhythmia syndrome

INTRODUCTION

Patients undergoing evaluation for an inherited arrhythmia syndrome undertake a series of ambulatory investigations including 24-h Holter monitor, exercise treadmill testing (ETT), and others. Patch monitors may simplify the evaluation, providing accurate arrhythmia evaluation and QT assessment.

METHODS AND RESULTS

Patients referred for evaluation of an inherited arrhythmia syndrome underwent standard investigations, including 12-lead electrocardiography (ECG), 24-h Holter monitoring, ETT, along with supplemental monitoring using a 7-day ECG patch monitor. Heart rates (HR), corrected QT intervals (QTc), and ectopic burden were compared across monitoring modalities. Among 35 patients that wore the patch monitor, the median age was 39 years (54% male). There was intermediate correlation between resting HR across modalities (r = .58-.66) and poor correlation of peak HR (r = .27-.39). There was intermediate correlation between resting QTc intervals across modalities (r = .72-.77) but negligible correlation between QTc intervals at peak HR across modalities (r = -.01 to -.06). There was good correlation in PAC and PVC ectopic burden across the Holter and patch monitor.

CONCLUSION

Patch monitors may simplify the evaluation of patients for an inherited arrhythmia syndrome and provide resting QT assessment over time. However, QTc interval comparison at peak HRs remains variable, and may be limited by the single-lead ECG vector when using the patch monitor. Apart from QTc intervals at peak HR, patch monitors demonstrated good correlation with the ECG and Holter monitor for other parameters.

Transethnic Genome-Wide Association Study Provides Insights in the Genetic Architecture and Heritability of Long QT Syndrome

Supplemental Digital Content is available in the text.

Long QT syndrome (LQTS) is a rare genetic disorder and a major preventable cause of sudden cardiac death in the young. A causal rare genetic variant with large effect size is identified in up to 80% of probands (genotype positive) and cascade family screening shows incomplete penetrance of genetic variants. Furthermore, a proportion of cases meeting diagnostic criteria for LQTS remain genetically elusive despite genetic testing of established genes (genotype negative). These observations raise the possibility that common genetic variants with small effect size contribute to the clinical picture of LQTS. This study aimed to characterize and quantify the contribution of common genetic variation to LQTS disease susceptibility.

Genetic Testing in Inherited Arrhythmias: Approach, Limitations, and Challenges

Genetic testing is playing an ever-expanding role in cardiovascular care and is becoming part of the "toolkit" for the cardiovascular clinician. In patients with inherited arrhythmias, genetic testing can confirm a suspected diagnosis, establish a diagnosis in unexplained cases, and help facilitate cascade family screening. Many inherited arrhythmia syndromes are monogenic diseases arising from a single pathogenic variant involved in the structure and function of cardiac ion channels or structural proteins. As such, "arrhythmia gene panels" will often cast a wide net for such heritable diseases. However, challenges may arise when genetic testing results are ambiguous, or when genetic testing results (genotype) and clinical phenotypes do not match. In cases of "genotype-phenotype matching," genetic results complement the clinical phenotype and genetic testing can be used in diagnosis, family screening, and occasionally prognostication. It becomes more challenging when genetic results are negative or noncontributory and "contradict" the clinical phenotype. "Genotype mismatches" can also occur when genotype-positive patients have no clinical phenotype, or when genetic testing results point towards a completely different disease than the clinical phenotype. We discuss an approach to genetic testing and review the challenges that may arise when interpreting genetic testing results. Genetic testing has opened a wealth of opportunities in the diagnosis, management, and cascade screening of inherited arrhythmia syndromes, but has also opened a "Pandora's box" of challenges. Genetic results should be interpreted with caution and in a multidisciplinary clinic, with support from genetic counsellors and an expert with a focused interest in cardiovascular genetics.

Pus Samples in Complicated Appendicitis: An Important Investigation or a Waste of Resources: A Prospective Cohort Study

BACKGROUND AND AIMS:

Appendicitis is a common presentation to hospital with appendectomy being the treatment of choice. Pre-operative administration of broad-spectrum antibiotics is common, but obtaining intra-abdominal pus samples is not. After an initial 6-month retrospective audit and departmental teaching on the importance of intra-peritoneal pus sampling, we aimed to determine whether intra-operative pus samples changed antibiotic management.

MATERIALS AND METHODS:

Following the initial audit cycle, a 6-month prospective cohort study was conducted. Clinical data were collected on a predetermined proforma to assess the effectiveness of the intervention and antibiotic prescribing practice. The data collected during the whole 1-year period was analyzed.

RESULTS:

During the 1-year period, 440 patients were identified as undergoing a laparoscopic procedure. After exclusion, 261 patients were identified as undergoing laparoscopic appendectomies, of which 141 (54%) were classified as complicated laparoscopic appendectomies. A total of 35 out of 141 (25%) pus samples were sent of which 24 (17%) resulted in positive cultures, with only nine of these positive cultures reported prior to the patient being discharged. No patient had their antibiotic regimen changed as a result of the culture results. There were three cases of cultures resistant to local antibiotics, but without significant clinical outcome. One of these patients developed a post-operative complication, but the antibiotic regimen was changed to broad spectrum rather than a specific antibiotic based on culture sensitivity. Of the 141 patients with complicated laparoscopic appendectomies, five (3.5%) developed post-operative complications: one readmission requiring a laparoscopic washout for pelvic collection, three (2%) cases of pelvic collections managed conservatively, and one case of prolonged paralytic ileus managed non-operatively.

CONCLUSION:

Overall, none of the patients with positive cultures had a change in prescribed antibiotics based on culture results. Hence, the routine practice of intra-peritoneal pus sampling following complicated appendicitis remains of little clinical value.

P90 A systematic review of spinal cord serum and cerebrospinal fluid biomarkers for use in degenerative cervical myelopathy

Objectives

Whilst radiological evidence of compression is the hallmark of degenerative cervical myelopathy [DCM], it is unable to stage or prognosticate. Moreover, asymptomatic spinal cord compression is common and therefore new methods of assessing spinal cord function are required. We aimed to: 1) Evaluate the evidence-base for serum and CSF biomarkers of spinal cord damage in diagnosis, prognosis or predicting response to treatment in DCM 2) Identify serum and CSF biomarkers of spinal cord damage studied in other conditions, which may have relevance to DCM.

Design

Scoping review.

Subjects

Human only.

Methods

A search of MEDLINE and EMBASE was performed. Studies involving DCM patients or biomarkers relevant to spinal cord pathobiology were included.

Results

852 results were screened, of which 83 were included. 9 studies explored 12 biomarkers in DCM. NFH (n=3), S100b and NSE (n=2) received most study. 74 studies explored a further 118 biomarkers in other conditions; S100b (n=13), NFH (n=11) and GFAP (n=10) received most study. Overall, 72 studies used targeted approaches, in which candidate biomarkers were chosen in advance. 11 used unbiased approaches, in which high throughput analyses identified candidate biomarkers during the study.

Conclusions

The evidence-base for use of biomarkers in DCM is limited. Whilst targeted approaches have identified a number of candidate spinal cord markers, few have shown clinical utility. There is a shift towards investigating panels of multiple markers and unbiased, high-throughput approaches.

Evaluating the Validity of a Bayesian Program for Predicting Stage in Hodgkin’s Disease

A Bayesian model that provides probabilistic information about the spread of malignancy in a Hodgkin’s disease patient has been developed at the Tufts New England Medical Center. In assessing the model’s reliability, it seemed important to use it to make predictions about patients other than those relevant to its construction. The accuracy of these predictions could then be tested statistically. This paper describes such a test, based on 243 Hodgkin’s disease patients of known pathologic stage. The results obtained were supportive of the model, and the test procedure might interest those wishing to determine whether the imperfections that attend any attempt to make probabilistic forecasts have gravely damaged their accuracy.

Relationship Between Sarcopenia and Frailty in the Toledo Study of Healthy Aging: A Population Based Cross-Sectional Study

INTRODUCTION

Frailty and sarcopenia are correlates of musculoskeletal aging that represent a state of vulnerability increasing the risk of negative health outcomes. Standardized definitions are lacking for both, and sometimes both concepts are used interchangeably. However, no large study has assessed the coexistence of these 2 entities in a cohort of older community-dwelling people.

METHODS

Data were taken from the Toledo Study of Healthy Aging (TSHA), a study of community-dwelling elderly (≥65 years). The study population consists of 1611 participants with frailty and sarcopenia assessments. For sarcopenia, we used 3 criteria: European Working Group on Sarcopenia in Older People (EWGSOP), the Foundation for the National Institutes of Health (FNIH), and the FNIH fitted to the cut-off points of our population [standardized FNIH (sFNIH)]. Frailty was assessed according to the Fried criteria with cut-off points adjusted to our population. We used logistic regression to assess the relationship between sarcopenia and frailty and measures of diagnostic accuracy to evaluate the potential use of sarcopenia as a diagnostic marker for frailty.

RESULTS

The mean age of the population was 75.42 years (±5.86). Overall, 72 (4.5%) were frail. In addition, 352 (21.8%), 332 (20.6%), and 453 (28.1%) participants were considered sarcopenic according to the EWGSOP, FNIH, and sFNIH criteria, respectively. The prevalence of frailty among those with sarcopenia was 8.2% (29/352), 15.7% (52/332), and 10.4% (47/453). Moreover, among frail people, the prevalence of sarcopenia was 40.27%, 72.2%, and 65.3% according to the used criteria. Sarcopenia showed a low sensitivity (<10%) but high specificity (>97%) for the diagnosis of frailty, with a low intercorrelation (Cramer V = 0.16, 0.40, and 0.30) between the 3 criteria and frailty. Using multivariate logistic regression, frailty was associated with sarcopenia according to EWGSOP [odds ratio (OR) = 1.67, 95% confidence interval (CI) = 0.95, 2.96], FNIH (OR = 10.61, 95% CI = 5.8, 19.4), and sFNIH (OR = 6.63, 95% CI =3.5, 12.53).

CONCLUSION

Frailty and sarcopenia are distinct but related conditions. Sarcopenia is not a useful clinical biomarker of frailty, but its absence might be useful to exclude frailty.