Category Archives: What’s New

Book Chapter – Advances in Cardiovascular Technology

Advances in Cardiovascular Technology – New Devices and Concepts

Chapter 36 – Innovation in Cardiovascular Bioelectronics

Rose T. Yin, Yeon Sik Choi, Kedar K. Aras, Helen S. Knight, Alana N. Miniovich, and Igor R. Efimov

Abstract

Advances in materials science have enabled new bioelectronics platforms for novel approaches to medicine. Bioelectronics for disease diagnosis and treatment that were once bulky have become miniaturized and lightweight. The rigid geometries that were previously incompatible with tissues and organs are now flexible and stretchable to conform to organ curvatures. Energy sources dependent on batteries can now harvest energy from mechanical motion, static electricity, light, ultrasound, and electromagnetic fields.

Materials at the tissue – bioelectronics interface inducing significant foreign body responses have been replaced by materials such as hydrogels and graphene that are much more biocompatible. These innovations have enabled the development of bioelectronics for the treatment of cardiovascular diseases, such as monitors, ablation, pacemaker, and implantable cardioverter defibrillator (ICD) therapy.

This portfolio of bioelectronic devices collects high-resolution data across multiple parameters and can deliver the pertinent electrotherapy. The bioelectronic conformal devices serve as the foundation of the medical internet-of-things, which will ultimately improve the accessibility of medicine, the efficiency of the healthcare system, and enhance human health.

A transient, closed-loop network of wireless, body-integrated devices for autonomous electrotherapy

Transient closed-loop system for temporary cardiac pacing

WHAT IS KNOWN?

  1. Cardiovascular implantable electronic devices (CIEDs) introduce risk of infections as well as limitations on patient quality of life.
  2. There is a need for minimally invasive devices that provide autonomous electrotherapy over a time frame that matches post-operative needs.

WHAT THIS STUDY ADDS

  1. We propose a transient, closed-loop system for temporary cardiac pacing that incorporates a wireless network of components including:
    • Temporary, bioresorbable, stretchable epicardial pacemaker,
    • Bioresorbable steroid-eluting interface that minimizes local inflammation and fibrosis
    • Subcutaneous, bioresorbable power harvesting unit
    • Set of soft, skin-interfaced sensors that capture ECG, HR etc., to track patient physiology.
    • Wireless RF module that transfers power to the harvesting unit
    • Soft skin-interfaced haptic actuator that communicates via mechanical vibrations
    • Handheld device with software module for real time data visualization and automated adaptive control
  2. The bioresorbable module for cardiac pacing undergoes complete dissolution by natural biological processes after a defined operating time frame. Moreover, the wireless battery recharge through the skin eliminates the need for transcutaneous wires.

LINK TO THE ARTICLE

Choi YS, Jeong H, Yin RT, Avila R, Pfenniger A, Yoo J, Lee JY, Tzavelis A, Lee YJ, Chen SW, Knight HS, Kim S, Ahn HY, Wickerson G, Vázquez-Guardado A, Higbee-Dempsey E, Russo BA, Napolitano MA, Holleran TJ, Razzak LA, Miniovich AN, Lee G, Geist B, Kim B, Han S, Brennan JA, Aras K, Kwak SS, Kim J, Waters EA, Yang X, Burrell A, San Chun K, Liu C, Wu C, Rwei AY, Spann AN, Banks A, Johnson D, Zhang ZJ, Haney CR, Jin SH, Sahakian AV, Huang Y, Trachiotis GD, Knight BP, Arora RK, Efimov IR, Rogers JA. A transient, closed-loop network of wireless, body-integrated devices for autonomous electrotherapy. Science. 2022 May 27;376(6596):1006-1012. doi: 10.1126/science.abm1703. Epub 2022 May 26. PMID: 35617386.

Hardware-Mappable Cellular Neural Networks for Distributed Wavefront Detection in Next-Generation Cardiac Implants

WHAT IS KNOWN?

  1. Organ conformal bioelectronics platform have enabled high-definition ventricular arrhythmia sensing, coupled with electrotherapy.
  2. However, current conformal electronics platforms do not have the ability to perform real time computing to detect arrhythmia rotors and and subsequently deliver appropriate therapy.

WHAT THIS STUDY ADDS?

  1. We propose the use of distributed computing algorithm based on cellular neural networks to provide high classification sensitivity, specificity, accuracy, and precision in detecting arrhythmia rotors and wavefronts.
  2. The compact and efficient computing solution is readily mappable to a memristor based hardware circuitry and could enable a closed-loop solution for smart arrhythmia detection and real-time therapy.

LINK TO THE ARTICLE

Yang Z, Zhang L, Aras K, Efimov IR, Adam GC. Hardware-Mappable Cellular Neural Networks for Distributed Wavefront Detection in Next-Generation Cardiac Implants. Adv. Intell. Syst., 2022.

The Secretome of Atrial Epicardial Adipose Tissue Facilitates Reentrant Arrhythmias by Myocardial Remodeling

Atrial EAT promotes arrhythmias
Atrial EAT promotes arrhythmias

WHAT IS KNOWN?

  1. Obesity is an independent risk factor for sudden cardiac death and atrial fibrillation.
  2. The molecular mechanisms underlying how atrial epicardial adipose tissue (EAT) can induce arrhythmias is not well understood.

WHAT THIS STUDY ADDS

  1. Atrial EAT induces electrophysiological remodeling of myocardium by decreasing electrical coupling, reducing IK1 and depolarizing the maximum diastolic potential.
  2. This results in slowed conduction and increased conduction heterogeneity, depolarized resting potential, which in turn, can facilitate reentrant arrhythmias.

LINK TO THE ARTICLE

Ernault AC, Verkerk AO, Bayer JD, Aras K, Agudo PM, Mohan RA, Veldkamp M, Kawasaki M, van Amersfoorth SCM, Driessen AHG, Efimov IR, de Groot J, Coronel R. The Secretome of Epicardial Adipose Tissue Facilitates Reentrant Arrhythmias by Myocardial RemodelingHeart Rhythm, 2022.

Maria Inês Francisco Gândara

Maria Inês Francisco Gândarra

Maria Inês Francisco Gândara.

Inês joined our lab as an international graduate student from NOVA school of science & technology, Lisbon, Portugal to pursue her M.S. thesis. I had the good fortune of being her thesis advisor. I am excited and happy to report that Inês successfully defended her dissertation and is now a proud graduate of NOVA University.

THESIS TITLE

Effects of spatial resolution on arrhythmia driver detection and localization

ABSTRACT

Arrhythmia is a cardiac rhythm disorder that can be fatal. Its treatment includes ab- lation of the cardiac tissue and/or defibrillation. Advances are being made for both treatment options to localize the culprit region and apply therapy directly where it is needed. However, success rates have been inconsistent, with frequent arrhythmia recurrence. A likely reason is the limited current resolution of mapping devices, that averages 4 mm. Higher resolution may improve localization of arrhythmia drivers, termed rotors, and consequently improve efficacy of treatment.

This study evaluates the effects of spa- tial resolution on arrhythmia dynamics, rotor tracking, and rotor localization. Optical data from ex vivo human hearts was used, being clinically relevant and with ultra-high spatial resolution. To simulate different resolutions, original data was downsampled by multiple factors and upsampled back to full resolution. Rotors were tracked for each sub-resolution and compared to the rotors in the original data. Further comparisons were made according to arrhythmia type, sex, anatomical region, and mapped surface. Accuracy profiles were created for both rotor detection and localization, describing how accuracy changed with spatial resolution and spatial accuracy.

Rotor detection accuracy for currently used mapping devices was found to be 57±4%. Localization accuracy is 61±7%. Detection accuracy was above 80% only for a resolution of 1.4 mm. Moreover, the detection and localization accuracies were affected by arrhythmia type, and rotor incidence was found to be higher in the endocardium. Therefore, current clinical rotor detection and localization accuracies can be expected to fall within a confidence interl,gttval of 47-67% and 46-75%, respectively. This means that a higher spatial resolution is needed in cardiac mapping devices than what is currently available.

For high accuracy, a resolution of at least 1.4 mm is required. The accuracy profiles provided in this thesis may serve as a guideline for future mapping device development.