Arrhythmogenic or dilated or desmoplakin cardiomyopathy? A challenging case managed by our multidisciplinary cardiogenetic team.

Arrhythmogenic cardiomyopathy (ACM), characterized by fibro or fibrofatty infiltration of the myocardium with a predominant arrhythmic presentation, is a genetically mediated cause of sudden cardiac death in the young and athletic individuals. We report a case of a severe form of biventricular ACM in a middle-aged man with a family history of cardiomyopathy-related young death. The proband was identified to harbor two novel mutations in the DES and DOLK genes and was managed comprehensively with a multidisciplinary team approach. This report reinforces the need for a dedicated cardiovascular genetics program as well as a population-specific genetic database in developing countries.

Results of comprehensive genetic testing in patients presenting to a multidisciplinary inherited heart disease clinic in India.

OBJECTIVES: This study aims to analyze the results of comprehensive genetic testing in patients presenting to a dedicated multidisciplinary inherited heart disease clinic in India. METHODS: All patients presenting to our clinic from August 2017 to October 2023 with a suspected inherited heart disease and consenting for genetic testing were included. The probands were grouped into familial cardiomyopathies namely hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), arrhythmogenic cardiomyopathy (ACM) and peripartum cardiomyopathy (PPCM), channelopathies namely congenital long QT syndrome (LQTS) and Brugada syndrome (BrS), and heritable connective tissue disorder namely Marfan Syndrome (MFS). Next generation sequencing (NGS) was used, and pre-test and post-test counseling were provided to probands and cascade screening offered to relatives. RESULTS: Mean age of the subjects (n=77; 48 probands, 29 relatives) was 43±18 years, 68% male and 44% symptomatic, with 36 HCM, 3 DCM, 3 ACM, 1 PPCM, 3 LQTS, 1 BrS and 1 MFS probands. The diagnostic yield of NGS-based genetic testing was 31%; variants of uncertain significance (VUS) were identified in 54%; and 15% were genotype-negative. Twenty-nine relatives from 18 families with HCM (n=12), DCM (n=3), ACM (n=2) and MFS (n=1) underwent genetic testing. The genotype positive probands / relatives and VUS carriers with strong disease phenotype and / or high risk variant were advised periodic follow-up; the remaining probands / relatives were discharged from further clinical surveillance. CONCLUSIONS: Genetic testing guides treatment and follow-up of patients with inherited heart diseases and should be carried out in dedicated multidisciplinary clinics with expertise for counseling and cascade screening of family members.

A robust multiplexed assay to quantify C1-inhibitor, C1q, and C4 proteins for in vitro diagnosis of hereditary angioedema from dried blood spot.

Hereditary angioedema (HAE) is a rare genetic disease caused by deficiency or dysfunction of C1 esterase inhibitor (C1-INH). Plasma C1-INH activity and concentrations of C1-INH and complement components 1q and 4 (C1q, C4) are critical to the HAE diagnosis. We describe a novel multiplexed assay to simultaneously measure C1-INH, C1q, and C4 levels in dried blood spot (DBS) of HAE patients. The blood proteins were extracted from 3 mm punches of DBS samples and were subsequently digested by trypsin. The signature peptide derived from each protein was quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Analyte-depleted blood was generated as a surrogate matrix for the preparation of calibration curves to overcome the interference of endogenous proteins, and the assay reproducibility was further monitored by assessing the signal of plasma transferrin as a house-keeping protein. The assay was fully validated following regulatory guideline, with a quantification range of 12.5-800 µg/mL for C1-INH and C4 and 3.13-200 µg/mL for C1q. The precision and accuracy ranged from 3.3%-9.8% and -8.2%-12.6%, respectively. All the patient samples exhibited C1-INH levels lower than normal range except the Type II patient and the C4 and C1q concentrations were as expected. Results from the DBS-based LC-MS assay were highly correlated with the ELISA data measured in plasma of the same subjects. The method described here offers unique advantages such as less invasive sampling, minimal blood processing, and easy transportation and sample storage, allowing, for the first time, C1-INH, C4, and C1q levels to be simultaneously determined in a drop of dried blood.

Prevalence of cardiovascular health risk behaviors in college-going women in a major metropolis in India.

There is an increasing incidence of cardiovascular disease (CVD) in Indian men and women of younger ages but research related to CVD risk behaviors in college-going women in India is limited. A cross-sectional questionnaire-based survey conducted among 554 students from two women's colleges in Chennai showed that there was an alarmingly high prevalence of unhealthy diet and inadequate exercise, a moderately high prevalence of psychosocial risk and a low prevalence of tobacco use and alcohol consumption. It is imperative to increase awareness and provide targeted interventions to help our young women adopt a heart-healthy lifestyle.

A first of its kind quantitative functional C1-esterase inhibitor lateral flow assay for hereditary angioedema point-of-care diagnostic testing.

Hereditary Angioedema (HAE) is a rare, autosomal dominant disease caused by mutations in SERPING1 gene leading to dysfunction/deficiency of C1-esterase inhibitor (C1-INH) protein and subsequent dysregulation of the contact system and bradykinin overproduction. As functional C1-INH (fC1-INH) levels are reduced in HAE types I and II (HAE-I/II), a specific, sensitive and accessible rapid diagnostic method to quantitate fC1-INH is crucial in diagnosing HAE-I/II. Previously, we developed/validated methods to detect fC1-INH levels in human plasma based on functional binding to C1s or FXIIa for C1-INH-based therapies. Quantitative fC1-INH immunoassay methods were converted to the Lateral flow assay (LFA) platform after identifying the best reagent/s pair. The assay was developed and optimized as a first of its kind LFA method for quantifying fC1-INH in human plasma to aid HAE point-of-care diagnosis. Receiver operating characteristic analysis was performed using normal control and HAE subject plasma samples to calculate area-under-curve and a cut-off point to distinguish normal versus HAE subject samples. LFA data was correlated with the conventional diagnostic assay for fC1-INH in HAE plasma samples and profiles matched for individual subjects. Here, we demonstrate a proof-of-concept for the quantitative fC1-INH LFA using normal and HAE plasma samples. We propose that the method could be used as a point-of-care test to diagnose HAE in a variety of settings, such as, a hospital or physician's office, at home or in an ambulance.

A multicentre retrospective study on quality and outcomes of cardiac rehabilitation programs in India.

Cardiac rehabilitation (CR) programs in India are comprehensive in nature, consist of multidisciplinary teams and demonstrate significant improvement in various clinical parameters. However, there is a disparity in patient evaluation, risk assessment, data collection and documentation. CR programs in India need to be streamlined to meet the quality indicators outlined by the international guideline recommendations.

Parallel comparison of three methodologies for measuring functional C1-inhibitor in Hereditary angioedema patients.

Hereditary angioedema (HAE) types I and II are characterized by functional C1 inhibitor (fC1-INH) deficiency which results in bradykinin overproduction. Sensitive, specific and robust methods to quantitate fC1-INH in human samples are required for diagnosing HAE and/or to measure pharmacodynamic activity of C1-INH drugs in clinical studies. To date, three methods have been reported in literature to measure fC1-INH: conventional chromogenic assay measuring residual C1-esterase activity, and immunoassays based on functional binding to either activated complement C1s or Factor XIIa/kallikrein. We used three qualified/validated fit-for purpose methods to quantitate fC1-INH in human plasma and to conduct a parallel comparison for diagnostic purposes and as a read-out for pharmacodynamic activity. Sensitivity and specificity were determined from the Receiver Operator Characteristics (ROC) curve analysis of the three fC1-INH methods through testing of fifty healthy control vs. HAE plasma samples. fC1-INH profile of fifteen HAE subjects, who underwent different treatment regimen in a cross-over Shire C1-INH clinical study, was analyzed in these three methods in parallel. A correlation analysis performed between these methods using data generated from clinical samples showed that profiles obtained from different fC1-INH methods matched for individual HAE subjects. Our findings suggest that functional binding immunoassay methods serve as reliable alternates for conventional chromogenic method to quantitate fC1-INH in human plasma samples with a better dynamic range of detection and ease of use. Of the two immunoassays used in this study, FXIIa-binding method gave better sensitivity, specificity, and correlation to the chromogenic method as a diagnostic method to distinguish HAE samples from healthy controls.

A novel functional C1 inhibitor activity assay in dried blood spot for diagnosis of Hereditary angioedema.

BACKGROUND: Hereditary angioedema (HAE) is a rare genetic disease caused by deficiency or dysfunction of C1 esterase inhibitor (C1-INH). Timely and accurate diagnosis is an ongoing challenge. Measurement of plasma C1-INH activity is currently the critical standard test. We describe a novel and highly robust point-of-care assay to quantify C1-INH activity in dried blood spot (DBS). METHODS: C1-INH was extracted from 3 mm punches of DBS samples and incubated with excess amount of C1 esterase (C1s). The mixture was subsequentially incubated with C1s substrate, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) quantitation of the enzyme reaction product. RESULTS: The assay was validated within a quantification range from 100 to 1500 mU/mL. The intra-day precision and accuracy ranged from 4.0% to 11.6% and -11.1% to -2.1%, and the inter-day precision and accuracy were 8.1-13.1% and -10.3% to 0.9%, respectively. Normal C1-INH activity (n = 103) ranged from 311 to 1090 mU/mL, whereas 23 out of 24 HAE patients exhibited C1-INH activity lower than 100 mU/mL. CONCLUSION: DBS specimen collection for measurement of functional C1-INH activity in a physician's office is straightforward and not limited by logistic considerations and therefore, appropriate for the diagnosis of HAE in high throughput diagnostic laboratories.

Outcomes of a multidisciplinary coronary heart disease prevention programme in southern India.

OBJECTIVE: Coronary heart disease (CHD) is a major cause for mortality and morbidity in India but the focus on lifestyle interventions is very low. This study aims to evaluate the role of a multidisciplinary CHD prevention programme in southern India. METHODS: All patients enrolled between May 2014 and March 2016 with CHD (disease group) or with risk factors but no CHD (risk group) were included. Participants attended one-two sessions per week for 6-12 weeks; each session lasted 90-120 min, including exercise and education, and was adapted to the participants' sociocultural requirements. Resting heart rate, systolic and diastolic blood pressure, body mass index (BMI), waist circumference (WC) and functional capacity (FC) were documented at start and end of programme. RESULTS: Disease group was older (61±10 vs 51±14  years, p<0.01), had lower BMI and WC (26±4 vs 30±7 kg/m2, p<0.01; 39±4 vs 42±5 inches, p<0.01), attended more sessions (12±7 vs 6±3, p<0.0001) and had higher completion rates (82% vs 53%, p=0.02) than the risk group. Programme-completers (n=45, 67%) showed significant improvement in health-related behaviour, angina threshold (in all 8 subjects with stable angina), BMI (p=0.03), WC (p<0.01) and FC (p<0.01). Follow-up for a period of 16±6 months showed continued adherence to the healthy behaviour (n=44, 1 lost to follow-up) and maintenance of anthropometric and FC parameters. CONCLUSIONS: A multidisciplinary approach to preventing CHD is lacking in India. This study shows that a comprehensive lifestyle intervention programme has significant benefits and can be incorporated in the routine management of all patients and at-risk individuals in the region.

Remarkable regression of coronary atherosclerosis: An interplay of pharmacotherapeutic and lifestyle factors.

Coronary heart disease is the leading cause of death in the world today. Regression of coronary atherosclerosis using a combination of drugs and lifestyle interventions has been reported. This letter describes three patients with remarkable reduction in angiographic stenosis of coronary arteries that is generally not considered feasible.

Soluble Fn14 Is Detected and Elevated in Mouse and Human Kidney Disease.

The cytokine TWEAK and its cognate receptor Fn14 are members of the TNF/TNFR superfamily and are upregulated in tissue injury to mediate local tissue responses including inflammation and tissue remodeling. We found that in various models of kidney disease, Fn14 expression (mRNA and protein) is upregulated in the kidney. These models include: lupus nephritis mouse models (Nephrotoxic serum Transfer Nephritis and MRL.Faslpr/lpr), acute kidney injury models (Ischemia reperfusion injury and Folic acid injury), and a ZSF-1 diabetic nephropathy rat model. Fn14 expression levels correlate with disease severity as measured by disease histology. We have also shown for the first time the detection of soluble Fn14 (sFn14) in the urine and serum of mice. Importantly, we found the sFn14 levels are markedly increased in the diseased mice and are correlated with disease biomarkers including proteinuria and MCP-1. We have also detected sFn14 in human plasma and urine. Moreover, sFn14 levels, in urine are significantly increased in DN patients and correlated with proteinuria and MCP-1 levels. Thus our data not only confirm the up-regulation of Fn14/TWEAK pathway in kidney diseases, but also suggest a novel mechanism for its regulation by the generation of sFn14. The correlation of sFn14 levels and disease severity suggest that sFn14 may serve as a potential biomarker for both acute and chronic kidney diseases.

Channelopathies - emerging trends in the management of inherited arrhythmias.

In spite of their relative rarity, inheritable arrhythmias have come to the forefront as a group of potentially fatal but preventable cause of sudden cardiac death in children and (young) adults. Comprehensive management of inherited arrhythmias includes diagnosing and treating the proband and identifying and protecting affected family members. This has been made possible by the vast advances in the field of molecular biology enabling better understanding of the genetic underpinnings of some of these disease groups, namely congenital long QT syndrome, catecholaminergic polymorphic ventricular tachycardia and Brugada syndrome. The ensuing knowledge of the genotype-phenotype correlations enables us to risk-stratify, prognosticate and treat based on the genetic test results. The various diagnostic modalities currently available to us, including clinical tools and genetic technologies, have to be applied judiciously in order to promptly identify those affected and to spare the emotional burden of a potentially lethal disease in the unaffected individuals. The therapeutic armamentarium of inherited arrhythmias includes pharmacological agents, device therapies and surgical interventions. A treatment strategy keeping in mind the risk profile of the patients, the local availability of drugs and the expertise of the treating personnel is proving effective. While opportunities for research are numerous in this expanding field of medicine, there is also tremendous scope for incorporating the emerging trends in managing patients and families with inherited arrhythmias in the Indian subcontinent.

Inherited arrhythmia syndromes leading to sudden cardiac death in the young: a global update and an Indian perspective.

Inherited primary arrhythmias, namely congenital long QT syndrome, Brugada syndrome and catecholaminergic polymorphic ventricular tachycardia, account for a significant proportion of sudden cardiac deaths in young and apparently healthy individuals. Genetic testing plays an integral role in the diagnosis, risk-stratification and treatment of probands and family members. It is increasingly obvious that collaborative efforts are required to understand and manage these relatively rare but potentially lethal diseases. This article aims to update readers on the recent developments in our knowledge of inherited arrhythmias and to lay the foundation for a national synergistic effort to characterize them in the Indian population.

Mutation location effect on severity of phenotype during exercise testing in type 1 long-QT syndrome: impact of transmembrane and C-loop location.

BACKGROUND: Targeted mutation site-specific differences have correlated C-loop missense mutations with worse outcomes and increased benefit of beta-blockers in LQT1. This observation has implicated the C-loop region as being mechanistically important in the altered response to sympathetic stimulation known to put patients with LQT1 at risk of syncope and sudden cardiac death. OBJECTIVE: The objective of this study was to determine if there is mutation site-specific response to sympathetic stimulation and beta-blockers using exercise testing. METHODS: This study is a retrospective review of LQT1 patients undergoing exercise testing at 3 academic referral centers. RESULTS: A total of 123 patients (age 28 ± 17 years, 59 male) were studied including 34 patients (28%) with C-loop mutations. There were no significant differences in supine, standing, peak exercise and 1-minute recovery QTc duration between patients with C-loop mutations and patients with alternate mutation sites. In 37 patients that underwent testing on and off beta-blockers, beta-blocker use was associated with a significant reduction in supine, standing and peak exercise QTc. This difference was not seen in the small group of patients (7/37) with C-loop mutations. There was no difference in QTc at 1 and 4 minutes into recovery. CONCLUSIONS: Genetically confirmed LQT1 patients in this study cohort with C-loop mutations did not demonstrate the expected increase in QTc in response to exercise, or resultant response to beta-blocker. The apparent increased risk of cardiac events associated with C-loop mutation sites and the marked benefit received from beta-blocker therapy are not reflected by exercise-mediated effects on QTc in this study population.