Up-regulated small-conductance calcium-activated potassium currents contribute to atrial arrhythmogenesis in high-fat feeding mice.

Aims: Metabolic syndrome (MetS) is associated with arrhythmias and cardiovascular mortality. Arrhythmogenesis in MetS results from atrial structural and electrical remodelling. The small-conductance Ca2+-activated K+ (SK) currents modulate atrial repolarization and may influence atrial arrhythmogenicity.

A Common East Asian aldehyde dehydrogenase 2*2 variant promotes ventricular arrhythmia with chronic light-to-moderate alcohol use in mice.

Chronic heavy alcohol use is associated with lethal arrhythmias. Whether common East Asian-specific aldehyde dehydrogenase deficiency (ALDH2*2) contributes to arrhythmogenesis caused by low level alcohol use remains unclear. Here we show 59 habitual alcohol users carrying ALDH2 rs671 have longer QT interval (corrected) and higher ventricular tachyarrhythmia events compared with 137 ALDH2 wild-type (Wt) habitual alcohol users and 57 alcohol non-users.

Levosimendan attenuates electrical alternans and prevents ventricular arrhythmia during therapeutic hypothermia in isolated rabbit hearts.

Background: Therapeutic hypothermia (TH) increases the susceptibility to ventricular arrhythmias (VAs) by prolonging action potential duration (APD) and facilitating arrhythmogenic spatially discordant alternans (SDA). Levosimendan, a calcium sensitizer, has been reported to shorten APD by enhancing the adenosine triphosphate (ATP)-sensitive K current.

Objective: The purpose of this study was to test the hypothesis that, during TH, levosimendan shortens the already prolonged APD, attenuates SDA, and prevents VA.

Skin sympathetic nerve activity and ventricular arrhythmias in acute coronary syndrome.

Background: Acute coronary syndrome (ACS) is major cause of ventricular arrhythmias (VAs) and sudden death. neuECG is a noninvasive method to simultaneously record skin sympathetic nerve activity (SKNA) and electrocardiogram.

Objective: The purpose of this study was to test the hypotheses that (1) ACS increases average SKNA (aSKNA), (2) the magnitude of aSKNA elevation is associated with VAs during ACS, and (3) there is a gender difference in aSKNA between patients without and with ACS.

Intelligent Bio-Impedance System for Personalized Continuous Blood Pressure Measurement.

Continuous blood pressure (BP) measurement is crucial for long-term cardiovascular monitoring, especially for prompt hypertension detection. However, most of the continuous BP measurements rely on the pulse transit time (PTT) from multiple-channel physiological acquisition systems that impede wearable applications. Recently, wearable and smart health electronics have become significant for next-generation personalized healthcare progress.

Temporal Clustering of Skin Sympathetic Nerve Activity Bursts in Acute Myocardial Infarction Patients.

Acute myocardial infarction (AMI) affects the autonomic nervous system (ANS) function. The aim of our study is to detect the particular patterns of ANS regulation in AMI. We hypothesize that altered ANS regulation in AMI patients causes synchronized neural discharge (clustering phenomenon) detected by non-invasive skin sympathetic nerve activity (SKNA).

Biomaterial-induced conversion of quiescent cardiomyocytes into pacemaker cells in rats.

Pacemaker cells can be differentiated from stem cells or transdifferentiated from quiescent mature cardiac cells via genetic manipulation. Here we show that the exposure of rat quiescent ventricular cardiomyocytes to a silk-fibroin hydrogel activates the direct conversion of the quiescent cardiomyocytes to pacemaker cardiomyocytes by inducing the ectopic expression of the vascular endothelial cell-adhesion glycoprotein cadherin. The silk-fibroin-induced pacemaker cells exhibited functional and morphological features of genuine sinoatrial-node cardiomyocytes in vitro, and pacemaker cells generated via the injection of silk fibroin in the left ventricles of rats functioned as a surrogate in situ sinoatrial node.

Paroxysmal atrial fibrillation prediction based on morphological variant P-wave analysis with wideband ECG and deep learning.

Background And Objective: Atrial fibrillation (AF) is one of the most frequent asymptomatic arrhythmias associated with significant morbidity and mortality. Identifying the susceptibility to AF based on routine or continuous ECG recording is of considerable interest. Despite several P-wave characteristics and skin sympathetic nerve activity (SKNA) linked to AF onset, neither factor has offered accurate predictability.

AI-Assisted Echocardiographic Prescreening of Heart Failure With Preserved Ejection Fraction on the Basis of Intrabeat Dynamics.

Objectives: The aim of this study was to establish a rapid prescreening tool for heart failure with preserved ejection fraction (HFpEF) by using artificial intelligence (AI) techniques to detect abnormal echocardiographic patterns in structure and function on the basis of intrabeat dynamic changes in the left ventricle and the left atrium.

Background: Although diagnostic criteria for HFpEF have been established, rapid and accurate assessment of HFpEF using echocardiography remains challenging and highly desirable.

Methods: In total, 1,041 patients with HFpEF and 1,263 asymptomatic individuals were included in the study.

Proinflammatory Cytokine Modulates Intracellular Calcium Handling and Enhances Ventricular Arrhythmia Susceptibility.

The mechanism of Interleukin-17 (IL-17) induced ventricular arrhythmia (VA) remains unclear. This study aimed to investigate the effect of intracellular calcium (Ca) handling and VA susceptibility by IL-17. The electrophysiological properties of isolated perfused rabbit hearts under IL-17 (20 ng/ml, = 6) and the IL-17 with neutralizer (0.

Bio-Impedance Measurement Optimization for High-Resolution Carotid Pulse Sensing.

Continuous hemodynamic monitoring is important for long-term cardiovascular healthcare, especially in hypertension. The impedance plethysmography (IPG) based carotid pulse sensing is a non-invasive diagnosis technique for measuring pulse signals and further evaluating the arterial conditions of the patient such as continuous blood pressure (BP) monitoring. To reach the high-resolution IPG-based carotid pulse detection for cardiovascular applications, this study provides an optimized measurement parameter in response to obvious pulsation from the carotid artery.

IPG-based field potential measurement of cultured cardiomyocytes for optogenetic applications.

Background: Electrophysiological sensing of cardiomyocytes (CMs) in optogenetic preparations applies various techniques, such as patch-clamp, microelectrode array, and optical mapping. However, challenges remain in decreasing the cost, system dimensions, and operating skills required for these technologies.

Objective: This study developed a low-cost, portable impedance plethysmography (IPG)-based electrophysiological measurement of cultured CMs for optogenetic applications.

Electrocardiogram lead selection for intelligent screening of patients with systolic heart failure.

Electrocardiogram (ECG)-based intelligent screening for systolic heart failure (HF) is an emerging method that could become a low-cost and rapid screening tool for early diagnosis of the disease before the comprehensive echocardiographic procedure. We collected 12-lead ECG signals from 900 systolic HF patients (ejection fraction, EF < 50%) and 900 individuals with normal EF in the absence of HF symptoms. The 12-lead ECG signals were converted by continuous wavelet transform (CWT) to 2D spectra and classified using a 2D convolutional neural network (CNN).

The frequency spectrum of sympathetic nerve activity and arrhythmogenicity in ambulatory dogs.

Background: Sympathetic nerve activity, heart rate (HR), and blood pressure (BP) all have very low frequency (VLF), low frequency (LF), and high frequency (HF) oscillations.

Objective: The purpose of this study was to test the hypothesis that the frequency spectra of subcutaneous nerve activity (ScNA), stellate ganglion nerve activity (SGNA), HR, and BP are important to cardiac arrhythmogenesis.

Methods: We used radiotransmitters to record SGNA, ScNA, HR, and BP in 6 ambulatory dogs and determined the dominant frequency and paroxysmal atrial tachyarrhythmias (PATs) episodes in 3-minute windows over a 24-hour period.

Non-invasive Recording of Parasympathetic Nervous System Activity on Auricular Vagal Nerve Branch.

The function of the autonomic nervous system (ANS) influences most of the physiological mechanisms. The popular non-invasive method to estimate the activities of the autonomic nervous system (ANS) is the heart rate variability (HRV). However, the HRV cannot provide real-time information of the ANS function.

Design and Construction of High-Frequency Cardiac Defibrillator for Small Animals.

The main goal of this research is to evaluate the defibrillation efficacy with the high-frequency waveform on ventricular fibrillation in small animals. A biphasic defibrillator with adjustable frequency was designed for this study. This custom-designed defibrillator can be adjusted to generate four different frequencies of 125, 250, 500, and 1000 Hz.

Reverse electromechanical modelling of diastolic dysfunction in spontaneous hypertensive rat after sacubitril/valsartan therapy.

Aims: Hypertension is a significant risk for the development of left ventricular hypertrophy, diastolic dysfunction, followed by heart failure and sudden cardiac death. While therapy with sacubitril/valsartan (SV) reduces the risk of sudden cardiac death in patients with heart failure and systolic dysfunction, the effect on those with diastolic dysfunction remains unclear. We hypothesized that, in the animal model of hypertensive heart disease, treatment with SV reduces the susceptibility to ventricular arrhythmia.

Rhodiola crenulata reduces ventricular arrhythmia through mitigating the activation of IL-17 and inhibiting the MAPK signaling pathway.

Purpose: Ventricular arrhythmia (VA) is related to inflammatory activity. Rhodiola crenulate (RC) and its main active component, salidroside, have been reported as anti-inflammatory agents. The aim of this study was to demonstrate the effect of RC and salidroside in preventing VA via the inhibition of IL-17 in an ischemic heart failure (HF) model.

Anti-Inflammatory and Antiarrhythmic Effects of Beta Blocker in a Rat Model of Rheumatoid Arthritis.

Background Patients with rheumatoid arthritis are at twice the risk of ventricular arrhythmia and sudden cardiac death as the general population. We hypothesize that β-blocker treatment of rheumatoid arthritis is antiarrhythmic by producing synergistic anticatecholaminergic and anti-inflammatory effects. Methods and Results Collagen-induced arthritis (CIA) was induced in Lewis rats by immunization with type II collagen in Freund's incomplete adjuvant.

Complex dynamics of skin sympathetic nerve activities as a prognostic predictor for critically ill patients.

Background: The skin sympathetic nerve activity (SKNA) is a new method to measure sympathetic nerve activity by using conventional ECG electrodes. We developed a novel approach to analyze the complexity of SKNA time series under different time scales and showed its prognostic significance in patients receiving critical care.

Methods: This study measured SKNA in patients admitted to an intensive care unit (ICU).

Early lactate changes improve the outcome prediction for extracorporeal membrane oxygenation.

Objectives: Serial lactate (clearance) data are commonly used for risk stratification in patients receiving veno-arterial extracorporeal life support (ECLS).

Methods: We retrospectively analysed 855 patients who had undergone ECLS due to cardiac (n = 578) and non-cardiac (n = 277) aetiologies between 2002 and 2013 at National Taiwan University Hospital. Serial lactate (clearance) data were collected before ECLS and at 8, 16, 24, 48 and 72 h after ECLS.

Organ-on-a-Chip: Opportunities for Assessing the Toxicity of Particulate Matter.

Recent developments in epidemiology have confirmed that airborne particulates are directly associated with respiratory pathology and mortality. Although clinical studies have yielded evidence of the effects of many types of fine particulates on human health, it still does not have a complete understanding of how physiological reactions are caused nor to the changes and damages associated with cellular and molecular mechanisms. Currently, most health assessment studies of particulate matter (PM) are conducted through cell culture or animal experiments.

Effects of high-frequency biphasic shocks on ventricular vulnerability and defibrillation outcomes through synchronized virtual electrode responses.

Electrical defibrillation is a well-established treatment for cardiac dysrhythmias. Studies have suggested that shock-induced spatial sawtooth patterns and virtual electrodes are responsible for defibrillation efficacy. We hypothesize that high-frequency shocks enhance defibrillation efficacy by generating temporal sawtooth patterns and using rapid virtual electrodes synchronized with shock frequency.

Graphene Oxide-Based Nanomaterials: An Insight into Retinal Prosthesis.

Retinal prosthesis has recently emerged as a treatment strategy for retinopathies, providing excellent assistance in the treatment of age-related macular degeneration (AMD) and retinitis pigmentosa. The potential application of graphene oxide (GO), a highly biocompatible nanomaterial with superior physicochemical properties, in the fabrication of electrodes for retinal prosthesis, is reviewed in this article. This review integrates insights from biological medicine and nanotechnology, with electronic and electrical engineering technological breakthroughs, and aims to highlight innovative objectives in developing biomedical applications of retinal prosthesis.