Kedar Aras

University at Buffalo, The State University of New York | SUNY Buffalo · Department of Physiology and Biophysics

Introduction: Myocardial ischemia is a pathological condition initiated by supply and demand imbalance of the blood to the heart. Previous studies suggest that ischemia originates in the subendocardium, i.e., that nontransmural ischemia is limited to the subendocardium. By contrast, we hypothesized that acute myocardial ischemia is not limited to...

Fluorescence optical imaging techniques have revolutionized the field of cardiac electrophysiology and advanced our understanding of complex electrical activities such as arrhythmias. However, traditional monocular optical mapping systems, despite having high spatial resolution, are restricted to a twodimensional (2D) field of view. Consequently, t...

Background: Abnormal QT intervals, long QT or short QT, have been epidemiologically linked with sudden cardiac death because of ventricular fibrillation (VF). Consequently, Food and Drug Administration recommends testing all pharmacological agents for QT toxicity as a risk factor for cardiac toxicity. Such tests assess QT/QTc interval, which repre...

The rigidity and relatively primitive modes of operation of catheters equipped with sensing or actuation elements impede their conformal contact with soft-tissue surfaces, limit the scope of their uses, lengthen surgical times and increase the need for advanced surgical skills. Here, we report materials, device designs and fabrication approaches fo...

Cellular Neural Networks In article number 2200032, Gina C. Adam and co‐workers present a closed‐loop distributed solution based on cellular neural network algorithms to detect abnormal wavefronts in cardiac signals recorded in human tissue. A chiplet‐based hardware implementation using memristors could support future low energy and painless cardia...

Temporary postoperative cardiac pacing requires devices with percutaneous leads and external wired power and control systems. This hardware introduces risks for infection, limitations on patient mobility, and requirements for surgical extraction procedures. Bioresorbable pacemakers mitigate some of these disadvantages, but they demand pairing with...

Artificial intelligence algorithms are being adopted to analyze medical data, promising faster interpretation to support doctors’ diagnostics. The next frontier is to bring these powerful algorithms to implantable medical devices. Herein, a closed‐loop solution is proposed, where a cellular neural network is used to detect abnormal wavefronts and w...

Background Epicardial Adipose Tissue (EAT) accumulation is associated with cardiac arrhythmias. The effect of EAT secretome (EATs) on cardiac electrophysiology remains largely unknown. Objective This study investigated the arrhythmogenicity of EATs and its underlying molecular and electrophysiological mechanisms. Methods We collected atrial EAT a...

Background Right ventricular outflow tract (RVOT) is a common source of ventricular tachycardia, which often requires ablation. However, the mechanisms underlying the RVOT’s unique arrhythmia susceptibility remain poorly understood due to lack of detailed electrophysiological and molecular studies of the human RVOT. Methods We conducted optical ma...

Miniature wireless conformal bioelectronics represent the next generation of devices for medical diagnosis and therapy. Advances in materials science enable these new bioelectronics platforms for novel approaches to medicine. New features of the next generation of cardiac implantable electronic devices feature high flexibility and they conform to t...

Flexible electronic/optoelectronic systems that can intimately integrate onto the surfaces of vital organ systems have the potential to offer revolutionary diagnostic and therapeutic capabilities relevant to a wide spectrum of diseases and disorders. The critical interfaces between such technologies and living tissues must provide soft mechanical c...

Defibrillation remains the only effective therapy against sudden cardiac death. However, the current coil-based lead ICD devices are limited by high defibrillation threshold (DFT) and low arrhythmia sensing resolution, which can result in inappropriate and painful shocks adversely affecting the quality of life. Emerging classes of materials and mec...

Rationale: Mitral valve prolapse (MVP) is a common valvopathy that leads to mitral insufficiency, heart failure and sudden death. Functional genomic studies in mitral valves are needed to better characterize MVP associated variants and target genes. Objective: To establish the chromatin accessibility profiles and assess functionality of variants an...

[This corrects the article DOI: 10.1371/journal.pone.0231695.].

We present a novel modification of genetic algorithm (GA) which determines personalized parameters of cardiomyocyte electrophysiology model based on set of experimental human action potential (AP) recorded at different heart rates. In order to find the steady state solution, the optimized algorithm performs simultaneous search in the parametric and...

Background - The mechanisms sustaining myocardial fibrillation remain disputed, partly due to a lack of mapping tools that can accurately identify the mechanism with low spatial resolution clinical recordings. Granger causality (GC) analysis, an econometric tool for quantifying causal relationships between complex time-series, was developed as a no...

Conformal electronics are stretchable, flexible electronic devices that can diagnose and treat tissue functions with high spatiotemporal resolution. These devices are comprised of a network of sensors and actuators, which include electrodes, photodiodes, thermocouples, LEDs, pressure transducers, and photovoltaic devices. Conformal electronics can...

Background: We previously developed a computational model to aid clinicians in positioning implantable cardioverter defibrillators (ICDs), especially in the case of abnormal anatomies that commonly arise in pediatric cases. We have validated the model clinically on the body surface; however, validation within the volume of the heart is required to...

We present a novel genetic algorithm-based solution to determine the set of cardiomyocyte model parameters based on experimental human action potential (AP) recordings. The novel approach is based on AP waveform dependence on the heart rate. In order to find the steady-state solution, optimized parameters include conductivities of ionic channels an...

This chapter summarizes the current understanding of fibrillation and defibrillation mechanisms, and also explores one of the leading hypotheses of defibrillation, the virtual electrode polarization (VEP) hypothesis. The VEP hypothesis of defibrillation presents the most comprehensive explanation of defibrillation. It is based on solid experimental...

Background: Computational models of myocardial ischemia often use oversimplified ischemic source representations to simulate epicardial potentials. The purpose of this study was to explore the influence of biophysically justified, subject-specific ischemic zone representations on epicardial potentials. Methods: We developed and implemented an im...

The biophysical basis for electrocardiographic evaluation of myocardial ischemia stems from the notion that ischemic tissues develop, with relative uniformity, along the endocardial aspects of the heart. These injured regions of subendocardial tissue give rise to intramural currents that lead to ST segment deflections within electrocardiogram (ECG)...

Myocardial ischemia is the response of the heart to reduced coronary blood flow, leading to changes in ST segment potentials. ST segment depression is regarded as an indicator of nontransmural myocardial ischemia; however, not all nontransmural ischemia results in ST depression. This apparent discrepancy may be the result of many complex factors in...

Heart failure (HF) is a major cause of morbidity and mortality worldwide. The global burden of HF continues to rise, with prevalence rates estimated at 1-2% and incidence approaching 5-10 per 1000 persons annually. The complex pathophysiology of HF impacts virtually all aspects of normal cardiac function - from structure and mechanics to metabolism...

We have developed a computer simulation to evaluate the success of Implantable Cardioverter Defibrillators (ICDs) in a patient specific manner. Though we have verified the simulations by means of surface recordings of shock potentials in humans, recordings of potentials within the heart and torso are needed to further verify the model for use in a...

The "Experimental Data and Geometric Analysis Repository", or EDGAR is an Internet-based archive of curated data that are freely distributed to the international research community for the application and validation of electrocardiographic imaging (ECGI) techniques. The EDGAR project is a collaborative effort by the Consortium for ECG Imaging (CEI,...

Current computational models of acute ischemia are deficient because of their inability to be validated against experimental data and their lack of geometric realism. Past models of ischemia have been based on geometric primitives or hearts for which no electrical measurements exist. One consequence is that it is necessary to make modeling assumpti...

Like any measurement involving discrete spatial sampling, mapping of the electrical activity in the heart requires interpolation to estimate the values of electric potential between and around measured values. Interpolation is never perfect but can often perform better using application specific approaches than with general purpose methods and card...

Electrocardiographic (ECG) ST segment shifts are often used as markers for detecting myocardial ischemia. Literature suggests that the progression of ischemia, occurs from the endocardium and spreads towards the epicardium, eventually becoming transmural. Our study with animal models has found the progression of ischemia, characterized by ST elevat...

Electrocardiographic (ECG) ST segment shifts are often used as markers for detecting myocardial ischemia. Literature suggests that the progression of ischemia, occurs from the endocardium and spreads towards the epicardium, eventually becoming transmural. Our study with animal models has found the progression of ischemia, characterized by ST elevat...

To gain performance, developers often build scientific applications in procedural languages, such as C or Fortran, which unfortunately reduces flexibility. To address this imbalance, the authors present CompuCell3D, a multitiered, flexible, and scalable problem-solving environment for morphogenesis simulations that's written in C++ using object-ori...

Morphogenesis governs the formation of pat-terns in embryonic cell development, which eventually dif-ferentiate into bone and organs. Patterning instabilities that occur during morphogenesis can be described by compu-tational models, such as the Cellular Potts Model (CPM). Multiscale, experimentally-motivated simulations have suc-cessfully used the...

Design patterns have been widely adopted for building flexible and extensible applications. This can come at a cost of reduced performance which may not be acceptable for computationally intensive scientific applications. We claim that there are certain design patterns that when used properly can enhance both system performance and flexibility and...