Browsing by Author "Om Shankar"

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A comprehensive review on CFD simulations of left ventricle hemodynamics: numerical methods, experimental validation techniques, and emerging trends
(Springer Science and Business Media Deutschland GmbH, 2024) Priyanshu Soni; Sumit Kumar; B. V. Rathish Kumar; Sanjay Kumar Rai; Ashish Verma; Om Shankar
Globally, high death rates due to heart failure are an essential topic in medical research. Cardiovascular disease is the leading cause of cardiac dysfunction and collapse, with high mortality and morbidity rates. Early diagnosis and prognosis of CVD will reduce the risk of cardiovascular conditions. It is essential to develop various tools that provide accurate, real-time insight into the heart's physiology, functionality, and cardiac events. Due to the dispersed nature of the information and the reported results, a comprehensive literature review is required because there is a shortage of data about the hemodynamics analysis of blood flow in the ventricular region. Therefore, reviewing the status of hemodynamics analysis of ventricle blood flow is the prime importance of this review article. This article reviews the numerous investigations conducted over the past 15 years to simulate ventricular blood flow using experimental and computational techniques on patient-specific models or idealized models with or without specific medical conditions. This article discusses the fundamentals of hemodynamic analysis, such as the geometry types of a particular cardiac phase, medical conditions, and medical imaging methods. Recent developments in hemodynamic analysis, such as AI, HPC, and digital twins, were also mentioned in this comprehensive review study. This review article concluded that improvements in medical image processing and data acquisition techniques are needed to obtain accurate information regarding the functioning of the heart. Our review of previous studies shows that blood flow simulation is developing into a proper medical tool for instant heart function diagnosis. © The Author(s), under exclusive licence to The Brazilian Society of Mechanical Sciences and Engineering 2024.
An open loop 0D-3D modeling of pulsatile hemodynamics for the diagnosis of a suspected coronary arterial disease with patient data
(American Institute of Physics Inc., 2023) Sumit Kumar; B. V. Rathish Kumar; Sanjay Kumar Rai; Om Shankar
Due to the high degree of curvature of the coronary arteries, normal blood flow patterns are disrupted, making them susceptible sites for stenosis and atherosclerosis, leading to decrease in flow. Myocardial ischemia and infarction are the results of this reduced myocardial flow perfusion. Therefore, we conducted an extensive hemodynamic analysis on a patient suspected to have chest pain because of coronary artery disease in order to recognize the processes behind behaviors instigated by intricate geometry of the coronary artery. First, using coronary computed tomography angiography data, which were obtained from an ethically approved data provider, a patient-specific model was reconstructed. Open-circuit resemblance lumped parameter network coupled with zero-three dimensional (0D-3D) model was built to mimic coronary pressure and flow. Hemodynamic parameters such as the flow streamlines, time-average wall shear stress, oscillatory shear index, flow rate, and relative resilience time were investigated using computational fluid dynamics. It is critical for cardiac specialists to adequately care for their patients and provide corrective therapies at early onset of coronary problems caused by myocardial infarctions and demand coronary bypass surgery and stenting. The open loop modeling approach with lumped parameter-based physiologically and geometrically realistic outflow pressures will assist cardiologists in analyzing blood dynamics using the medically imaged coronary arteries of their patients and computing the magnitude of the hemodynamic parameters to provide them with a reliable assessment of the risk of coronary arterial disease for their patients. © 2023 Author(s).
Cardiac arrhythmia beat classification using DOST and PSO tuned SVM
(Elsevier Ireland Ltd, 2016) Sandeep Raj; Kailash Chandra Ray; Om Shankar
Background and objective The increase in the number of deaths due to cardiovascular diseases (CVDs) has gained significant attention from the study of electrocardiogram (ECG) signals. These ECG signals are studied by the experienced cardiologist for accurate and proper diagnosis, but it becomes difficult and time-consuming for long-term recordings. Various signal processing techniques are studied to analyze the ECG signal, but they bear limitations due to the non-stationary behavior of ECG signals. Hence, this study aims to improve the classification accuracy rate and provide an automated diagnostic solution for the detection of cardiac arrhythmias. Methods The proposed methodology consists of four stages, i.e. filtering, R-peak detection, feature extraction and classification stages. In this study, Wavelet based approach is used to filter the raw ECG signal, whereas Pan–Tompkins algorithm is used for detecting the R-peak inside the ECG signal. In the feature extraction stage, discrete orthogonal Stockwell transform (DOST) approach is presented for an efficient time-frequency representation (i.e. morphological descriptors) of a time domain signal and retains the absolute phase information to distinguish the various non-stationary behavior ECG signals. Moreover, these morphological descriptors are further reduced in lower dimensional space by using principal component analysis and combined with the dynamic features (i.e based on RR-interval of the ECG signals) of the input signal. This combination of two different kinds of descriptors represents each feature set of an input signal that is utilized for classification into subsequent categories by employing PSO tuned support vector machines (SVM). Results The proposed methodology is validated on the baseline MIT-BIH arrhythmia database and evaluated under two assessment schemes, yielding an improved overall accuracy of 99.18% for sixteen classes in the category-based and 89.10% for five classes (mapped according to AAMI standard) in the patient-based assessment scheme respectively to the state-of-art diagnosis. The results reported are further compared to the existing methodologies in literature. Conclusions The proposed feature representation of cardiac signals based on symmetrical features along with PSO based optimization technique for the SVM classifier reported an improved classification accuracy in both the assessment schemes evaluated on the benchmark MIT-BIH arrhythmia database and hence can be utilized for automated computer-aided diagnosis of cardiac arrhythmia beats. © 2016 Elsevier Ireland Ltd
Cardiovocal syndrome - A rare presentation of primary pulmonary hypertension
(Elsevier, 2014) Om Shankar; Balaji Vijaykumar Lohiya
Primary pulmonary hypertension is a well known entity with characteristic features more common in females presenting commonly with dyspnea. However primary pulmonary hypertension presenting as hoarseness of voice is rare occurring most likely due to compression of left recurrent laryngeal nerve between normal aorta and dilated tense pulmonary artery. Here we are presenting a case of 19 year old boy with primary pulmonary hypertension who presented with hoarseness of voice as predominant symptom. © 2014, Cardiological Society of India. All rights reserved.
Development of robust, fast and efficient QRS complex detector: a methodological review
(Springer Netherlands, 2018) Sandeep Raj; Kailash Chandra Ray; Om Shankar
The basis and reliability for timely diagnosis of cardiovascular diseases depend on the robust and accurate detection of QRS complexes along with the fiducial points in the electrocardiogram (ECG) signal. Despite, the several QRS detection algorithms reported in the literature, the development of an efficient QRS detector remains a challenge in the clinical environment. Therefore, this article summarizes the performance analysis of various QRS detection techniques depending upon three assessment factors which include robustness to noise, computational load, and sensitivity validated on the benchmark MIT-BIH arrhythmia database. Moreover, the limitations of these algorithms are discussed and compared with the standard signal processing algorithms, followed by the future suggestions to develop a reliable and efficient QRS methodology. Further, the suggested method can be implemented on suitable hardware platforms to develop smart health monitoring systems for continuous and long-term ECG assessment for real-time applications. © 2018, Australasian College of Physical Scientists and Engineers in Medicine.
Effect of rheological models on pulsatile hemodynamics in a multiply afflicted descending human aortic network
(Taylor and Francis Ltd., 2024) Sumit Kumar; B.V. Rathish Kumar; S.K. Rai; Om Shankar
In the cardiovascular diseased (CVD) conditions, it is essential to choose a suitable rheological model for capturing the correct physics behind the hemodynamic in the multiply afflicted diseased arterial network. This study investigates the effect of blood rheology on hemodynamics in a blood vessel with abdominal aortic aneurysm (AAA) and right internal iliac stenosis (RIIAS). A model with AAA and RIIAS is reconstructed from a human subject’s computed tomography (CT) data. Localized mesh generation and pulsatile inflow condition are considered. Non-Newtonian models such as the Power-law, Carreau, Cross, and Herschel Berkley models are used in simulations. The outcome from a validated computational model is compared with the Newtonian model to identify the suitable model for dealing with pathological complications under consideration. The capabilities and significance of various rheological models are also examined via Wall Pressure (WP), Wall Shear Stress (WSS), velocity, Global non-Newtonian importance factor (IG), Vorticity Streamlines, and Swirling Strength. It is noted that during the entire cardiac cycle, the IG factor of the cross model is found to be relatively more significant. Power Law depicts larger IG factor during peak systole and early diastole. Also, the cross model depicts larger WSS, WPS, swirling strength distribution and vorticity during the peak systolic and diastolic phases It is noted that IG ∼0.02 is an appropriate non-Newtonian blood activity cut-off value in the descending abdominal artery having AAA and RIIAS. The critical important WSS values are in the range of 0–9 Pa which is stated in WSS contour plot. © 2023 Informa UK Limited, trading as Taylor & Francis Group.
Histological changes of myocardium in dilated cardiomyopathy
(Reed Elsevier India Pvt. Ltd., 2017) Prasenjit Bose; Om Shankar; Barkha Singh; Rubi Bhola; Royana Singh
Introduction For patients with acute dilated cardiomyopathy, definition of prognosis and of clinical features predictive of outcome is particularly important due to the availability of cardiac transplantation and other innovative treatment strategies. Exact prevalence of DCM in India is not known. The disease is reported to be more prevalent and aggressive in Blacks and in females, while a few other reports had shown a preponderance of males. Methods The present study was undertaken on 60 heart samples, out of which 10 heart samples were enlarged and dilated compared to the control samples. The heart muscle samples were dissected and stained for microscopic evaluation. Result The heart tissue affected with dilated cardiomyopathy showed variation in myocyte size, transmural scars, fibrofatty change, fibrosis and deposition of collagen fibres, as compared to the normal heart tissue, Discussion Dilated cardiomyopathy leads to heart failure which can cause death. So, it is important to know the changes occurring in a heart due to dilated cardiomyopathy for the prognosis and further treatment for the disease. The finding ranges from minimal change to many other variation in the myocytes which is discussed further. © 2017
In-silico study of transcription factor binding elements of human PAX gene family members
(2013) Rashmi; V.K. Singh; A.N. Gangopadhyay; G.L. Shah; A. Khanna; T.M. Mohapatra; Om Shankar; Royana Singh
PAX gene family members, tissue specific transcription factors mainly involved, in the formation of tissues and. organs during embryonic development and has important role in transcriptional regulation. The presence of consensus paired domain play significant role in DNA-binding transcription regulation with PAX domain. Regulatory behavior of PAX family members were determined using cis-acting elements study and repeat identification. The study helped in investigating the potential conserved motifs in the paired domain. Further, investigation of cis-acting elements was done to elucidate the function for each PAX members and then repeat analyses and their correlation with functional elements were done. The study illustrates that the cis-acting elements are involved in tissue specific developmental expression and transcription al regulation of PAX family members. Further, based on physiochemical property study of these PAX gene family members it was found that they are mainly Ser, Pro, Gly and Ala rich amino acids. It was found that repeats containing functional DNA motifs interact with signature motifs of paired domain. The mam six signature motifs NQLGG, NGRPLP, RPC, SR, GCVSKIL and PGAIGGSKP are involved in interaction. Altogether, this study provides new insights into the regulatory behavior of upstream region of each PAX members and its effect in trans criptional regulation and developmental expression of these PAX members with involvement in disease management. © 2013 Asian Network for Scientific Information.
Percutaneous transcatheter occlusion of large pulmonary arteriovenous fistula with Amplatzer Septal Occluder in a young cyanotic girl
(Wolters Kluwer Medknow Publications, 2024) K. Arun Kumar; Soumik Ghosh; Neeraj Awasthy; Om Shankar
For most instances, percutaneous transcatheter intervention has replaced surgical procedure as the preferred treatment for pulmonary arteriovenous fistulas (PAVFs). Despite its efficacy in interventional occlusions of small- to medium-sized PAVFs, 'classic' devices such as detachable balloons and intravascular coils are not recommended for bigger fistulas due to the potential risk of embolization to the systemic circulation. This case report is a unique case of a 17-year-old cyanotic girl who had a large symptomatic solitary PAVF that was effectively closed with a 26 mm Amplatzer Septal Occlude (ASO) device. The PAVF was located in the lower right lobe of the lung. The position of the device in situ occluding the feeding channel was verified by computed tomography pulmonary angiography and postprocedure echocardiography, which also revealed the obliteration of the right-to-left shunt. © 2024 Heart India.
Piezoelectric catalyst BaTiO3 and K0.5Na0.5NbO3 induced cellular and antibacterial response in poly (vinylidene fluoride) for self-powered implants for orthopedic applications
(Elsevier B.V., 2025) Kuntal Kumar das; Urvashi Kesarwani; Ravi Prakash; Pralay Maiti; Om Shankar; Ashutosh Kumar Dubey
Despite of excellent biocompatibility of piezoelectric poly(vinylidene fluoride) (PVDF), lower resistance towards bacteria and piezoelectric coefficient restricts it's widespread application as self-powered implant. Towards this end, this study investigates the effect of incorporation of piezo-catalysts BaTiO3 (BT) and K0.5Na0.5NbO3 (KNN) into PVDF on piezo-catalytic characteristics, cellular and antibacterial response. Thin films of PVDF and its composites were prepared using the solvent casting method and hot compression molding. The piezo-catalytic response is observed to be notably higher in the composites than that of pure PVDF. The measured values of voltage, and power for PVDF, PVDF-10 wt% BT (PVDF-10BT) and PVDF-10 wt% KNN (PVDF-10KNN) are (24 V, ∼4.4 µW/cm2), (92 V, ∼15.8 µW/cm2) and (103 V, ∼19.4 µW/cm2), respectively. The presence of piezo-catalyst BT and KNN significantly enhance the cell proliferation, osteogenic differentiation (ALP) of MG-63 osteoblast-like cells and hemocompatibility. Incorporation of piezo-catalysts is observed to improve significantly the antibacterial response against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) due to a higher production of reactive oxygen species. These results suggest that PVDF modified with BaTiO3 and K0.5Na0.5NbO3 piezo-catalysts are promising candidates as self-powered implants for orthopedic applications. © 2025 Elsevier B.V.
Religious beliefs, patient–doctor interaction and resilience as predictors for treatment decisions and health outcomes of heart patients
(Routledge, 2019) Sanjay Kumar; Purnima Awasthi; Om Shankar
Treatment decision-making in chronic illness poses long-lasting effects on the health status of patients. In Western individualistic cultures, they are independently taken by the individual in collaboration with doctors contrary to the collectivistic Indian context, where it’s decided by families with little or no involvement of patients. Religious beliefs, patient–doctor interaction, and resilience measures of 100 CAD patients were used to assess their religious beliefs, patient–doctor interaction, and resilience (predictors). Hierarchical Regression Analysis was conducted to test for the significance of the proposed model. Religious beliefs, patient–doctor interaction, and resilience collectively predicted the significant change in decision-making styles, somatic symptoms, anxiety, social dysfunctions, depression, and general health total of the participants. While the treatment decision-making is heavily contingent upon the social factors namely–religious beliefs, patient–doctor interaction, and resilience, there may yet be some underlying psychological factors that have not been explored in the present study. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.
Survival and Clinical Outcomes After Single-vessel Percutaneous Coronary Intervention Using Drug-eluting Stent: An Observational and Follow-up Study in a Tertiary Care Center in the Gangetic Plains of North India
(Journal of Association of Physicians of India, 2025) Soumik Ghosh; Rajpal Prajapati; Arjun Tandon; Amit K. Gauraw; Kumar Amit; Om Shankar
Introduction: Percutaneous coronary intervention (PCI) with drug-eluting stents (DES) has transformed the management of coronary artery disease (CAD), particularly for single-vessel disease (SVD), by reducing restenosis rates. However, long-term survival data following PCI in North Indian populations are limited. This study aimed to evaluate survival and clinical outcomes after PCI with DES and identify factors associated with mortality and adverse events, such as chest pain, dyspnea, and bleeding. Materials and methods: This observational cohort study at Sir Sunder Lal Hospital, Banaras Hindu University, included 1,112 adult patients undergoing single-vessel PCI with DES. Patients were followed for 18 months via outpatient assessments and telephonic interviews to assess survival, chest pain, dyspnea, and bleeding. Data were analyzed using IBM SPSS Statistics (Version 25.0). Continuous variables were reported as mean ± SD, and categorical data as frequencies and percentages. Chi-square and independent t-tests were used, with a 5% significance level. Results: Of the 782 patients who were successfully followed up after 18 months, 740 (94.62%) were alive, and 42 (5.38%) had died. Significant factors associated with mortality included older age (p = 0.013), history of hospitalization (p < 0.001), chest pain (p < 0.001), dyspnea (p < 0.001), and bleeding (p < 0.001). Acute coronary syndrome (ACS) was the leading cause of death (52.3%), followed by post-PCI complications. Conclusion: PCI with DES demonstrated a high survival rate in North Indian patients with SVD. Key predictors of mortality were age, history of hospitalization, and post-PCI symptoms, emphasizing the need for long-term follow-up and aggressive management of symptoms to improve outcomes. ©The Author(s).
Tetralogy of Fallot with Holt-Oram syndrome
(Elsevier B.V., 2012) Vikas Kumar; Vikas Agrawal; Dharmendra Jain; Om Shankar
Holt-Oram syndrome (HOS) is characterised by mild to severe congenital cardiac defects and skeletal abnormalities of the upper limb. This syndrome is also referred to as Hand-Heart syndrome. The most common cardiac disorder is an ostium secundum detected an atrial septal defect (ASD), followed by ventricular septal defect (VSD) and ostium primum ASD. We report a case of HOS with tetralogy of Fallot (TOF). This association is very rare and is hardly reported in the literature. © 2012. Cardiological Society of India. All rights reserved.
The pulsatile 3D-Hemodynamics in a doubly afflicted human descending abdominal artery with iliac branching
(Taylor and Francis Ltd., 2023) Sumit Kumar; S.K. Rai; B.V. Rathish Kumar; Om Shankar
The study of patient-specific human arterial flow dynamics is well known to face challenges like a) apt geometric modelling, b) bifurcation zone meshing, and c) capturing the hemodynamic prone to variations with multiple disease complications. Due to aneurysms and stenosis in the same arterial network, the blood flow dynamics get affected, which needs to be explored. This study develops a new protocol for accurate geometric modelling, bifurcation zone meshing and numerically investigates the arterial network with abdominal aortic aneurysms (AAA) and right internal iliac stenosis (RIIAS). A realistic arterial model is reconstructed from the computed tomography (CT) data of a human subject. To understand the combined effect of the aneurysm and aortoiliac occlusive diseases in a patient, an arterial network with AAA, RIIAS, multiple branches tapering, and curvature has been considered. Clinically significant pulsatile blood flow simulations have been carried out to trace the alteration in the flow dynamics with multiple pathological complications under consideration. The transient blood flow dynamics are investigated via wall shear stress, wall pressure, velocity contour, streamlines, vorticity, and swirling strength. During the systolic deceleration phase, the rhythmic nested rapid secondary oscillatory WSS, adverse pressure gradients, high WSS, and high WP bands are noticed. Also, the above studies will help researchers, clinicians, and doctors understand the influence of morphological changes on hemodynamics in cardiovascular studies. © 2022 Informa UK Limited, trading as Taylor & Francis Group.
Tissue-engineered vascular grafts for cardiovascular disease management: Current strategies, challenges, and future perspectives
(John Wiley and Sons Inc, 2024) Kuntal Kumar Das; Ruchi Mishra Tiwari; Om Shankar; Pralay Maiti; Ashutosh Kumar Dubey
Cardiovascular diseases are the leading cause of mortality which primarily occurs due to the blood vessel obstruction or narrowing. Surgical procedures such as, coronary artery and peripheral artery bypass grafting frequently require vascular grafts for long-term revascularization. However, using autogenous vessels, such as the internal thoracic artery and saphenous vein, especially for vessels with diameters less than 6 mm, are associated with number of concerns due to limited availability, invasive retrieval procedures, and aptness. To overcome these limitations, the development of tissue-engineered vascular grafts (TEVGs) is in continuous thrust. This review comprehensively provides the potentiality of a range of artificial and naturally occurring biopolymers and their fabrication techniques, cell sources and seeding techniques to realize the state-of-the-art TEVGs. Moreover, this review article presents a synopsis of insights obtained from a variety of in vitro and in vivo studies, including human clinical trials. It underscores the need for further exploration into key areas such as optimal cell sources, seeding techniques, mechanical properties, hemodynamics, graft integration, the impact of patient conditions, optimum burst pressure, sufficient suture strength, hydrophilicity, biodegradability, and related factors. In summary, the review offers insights into the current strategies, challenges, and future perspectives of TEVG. © 2024 The Author(s). MedComm – Biomaterials and Applications published by John Wiley & Sons Australia, Ltd on behalf of Sichuan International Medical Exchange & Promotion Association (SCIMEA).