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https://www.readbyqxmd.com/read/29217881/reduced-baroreflex-sensitivity-decreased-heart-rate-variability-with-increased-arterial-stiffness-in-predialysis
#1
C Lal, M Kaur, A K Jaryal, K K Deepak, D Bhowmik, S K Agarwal
High cardiovascular morbidity and mortality is observed in predialytic chronic kidney disease (CKD) patients. The underlying mechanism of cardiovascular dysfunction often remains unclear. The present study was designed to perform multiparametric assessment of baroreflex sensitivity (BRS), arterial stiffness indices, and cardiovascular variabilities (heart rate variability [HRV] and blood pressure variability [BPV]) together in predialytic CKD patients; compare it with normal healthy controls; and determine their relationships in predialytic nondiabetic CKD patients...
November 2017: Indian Journal of Nephrology
https://www.readbyqxmd.com/read/29216239/effects-of-early-afterdepolarizations-on-excitation-patterns-in-an-accurate-model-of-the-human-ventricles
#2
Enid Van Nieuwenhuyse, Gunnar Seemann, Alexander V Panfilov, Nele Vandersickel
Early Afterdepolarizations, EADs, are defined as the reversal of the action potential before completion of the repolarization phase, which can result in ectopic beats. However, the series of mechanisms of EADs leading to these ectopic beats and related cardiac arrhythmias are not well understood. Therefore, we aimed to investigate the influence of this single cell behavior on the whole heart level. For this study we used a modified version of the Ten Tusscher-Panfilov model of human ventricular cells (TP06) which we implemented in a 3D ventricle model including realistic fiber orientations...
2017: PloS One
https://www.readbyqxmd.com/read/29148067/should-theophylline-be-added-to-the-j-wave-syndrome-therapeutic-armamentarium
#3
EDITORIAL
Charles Antzelevitch, Sami Viskin
The substrate for both early repolarization syndrome (ERS) and Brugada syndrome (BrS), the so-called J wave syndromes, has been shown to develop as a consequence of genetic variants causing a loss of function of inward currents such sodium (INa ) and calcium (ICa ) channel currents or a gain of function in outward currents such as the transient outward current (Ito ). These changes in ion channel function result in an outward shift of the balance of currents active during the early phases of the epicardial action potential in the right ventricular outflow tract (RVOT) of the heart in the case BrS and in the inferior left ventricle in the case of ERS...
November 16, 2017: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/29121655/experimental-blunt-chest-trauma-induced-myocardial-inflammation-and-alteration-of-gap-junction-protein-connexin-43
#4
Miriam Kalbitz, Elisa Maria Amann, Belinda Bosch, Annette Palmer, Anke Schultze, Jochen Pressmar, Birte Weber, Martin Wepler, Florian Gebhard, Hubert Schrezenmeier, Rolf Brenner, Markus Huber-Lang
OBJECTIVE: Severe blunt chest trauma in humans is associated with high mortality rates. Whereas lung tissue damage and lung inflammation after blunt chest trauma have extensively been investigated, the traumatic and posttraumatic effects on the heart remain poorly understood. Therefore, the purpose of this study was to define cardiac injury patterns in an experimental blunt chest trauma model in rats. METHODS: Experimental blunt chest trauma was induced by a blast wave in rats, with subsequent analysis of its effects on the heart...
2017: PloS One
https://www.readbyqxmd.com/read/29104543/simultaneous-quantification-of-spatially-discordant-alternans-in-voltage-and-intracellular-calcium-in-langendorff-perfused-rabbit-hearts-and-inconsistencies-with-models-of-cardiac-action-potentials-and-ca-transients
#5
Ilija Uzelac, Yanyan C Ji, Daniel Hornung, Johannes Schröder-Scheteling, Stefan Luther, Richard A Gray, Elizabeth M Cherry, Flavio H Fenton
Rationale: Discordant alternans, a phenomenon in which the action potential duration (APDs) and/or intracellular calcium transient durations (CaDs) in different spatial regions of cardiac tissue are out of phase, present a dynamical instability for complex spatial dispersion that can be associated with long-QT syndrome (LQTS) and the initiation of reentrant arrhythmias. Because the use of numerical simulations to investigate arrhythmic effects, such as acquired LQTS by drugs is beginning to be studied by the FDA, it is crucial to validate mathematical models that may be used during this process...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/29030236/long-term-aerobic-exercise-in-calsequestrin2-knockout-mice-accentuates-vagal-antagonism-during-%C3%AE-adrenergic-stimulation-which-restricts-heart-rate-acceleration-and-paradoxically-increases-abnormal-ryanodine-receptor-calcium-leak-in-ventricular-myocytes
#6
Hsiang-Ting Ho, Senthil Thambidorai, Björn C Knollmann, George E Billman, Sandor Györke, Anuradha Kalyanasundaram
BACKGROUND: Long-term aerobic exercise alters autonomic balance, which may not be favorable in heart rate (HR)-dependent arrhythmic diseases including catecholaminergic polymorphic ventricular tachycardia (CPVT) because of preexisting bradycardia and increased sensitivity to parasympathetic stimulation. OBJECTIVE: The purpose of this study was to determine whether long-term exercise-induced autonomic adaptations modify CPVT susceptibility. METHODS: We determined exercise-induced parasympathetic effects on HR, arrhythmia incidence, and intracellular sarcoplasmic reticulum (SR) Ca(2+) leak in atrial (ACM) and ventricular (VCM) cardiomyocytes, in exercised (EX) calsequestrin knockout (CASQ2(-/-)) mice, a model of CPVT...
October 10, 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/29016724/triggered-intracellular-calcium-waves-in-dog-and-human-left-atrial-myocytes-from-normal-and-failing-hearts
#7
Gary L Aistrup, Rishi Arora, Søren Grubb, Shin Yoo, Benjamin Toren, Manvinder Kumar, Aaron Kunamalla, William Marszalec, Tej Motiwala, Shannon Tai, Sean Yamakawa, Satya Yerrabolu, Francisco J Alvarado, Hector H Valdivia, Jonathan M Cordeiro, Yohannes Shiferaw, John Andrew Wasserstrom
Aims: Abnormal intracellular Ca2+ cycling contributes to triggered activity and arrhythmias in the heart. We investigated the properties and underlying mechanisms for systolic triggered Ca2+ waves in left atria from normal and failing dog hearts. Methods and results: Intracellular Ca2+ cycling was studied using confocal microscopy during rapid pacing of atrial myocytes (36 °C) isolated from normal and failing canine hearts (ventricular tachypacing model). In normal atrial myocytes (NAMs), Ca2+ waves developed during rapid pacing at rates ≥ 3...
November 1, 2017: Cardiovascular Research
https://www.readbyqxmd.com/read/28970285/calcium-dependent-arrhythmogenic-foci-created-by-weakly-coupled-myocytes-in-the-failing-heart
#8
Di Lang, Daisuke Sato, Yan Jiang, Kenneth S Ginsburg, Crystal M Ripplinger, Donald M Bers
Rationale: Intercellular uncoupling and Ca mishandling can initiate triggered ventricular arrhythmias. Spontaneous Ca release activates inward current which depolarizes membrane potential (Vm) and can trigger action potentials in isolated myocytes. However, cell-cell coupling in intact hearts limits local depolarization and may protect hearts from this arrhythmogenic mechanism. Traditional optical mapping lacks the spatial resolution to assess coupling of individual myocytes. Objective: We investigate local intercellular coupling in Ca-induced depolarization in intact hearts, using confocal microscopy to measure local Vm and intracellular [Ca(2+)] ([Ca]i) simultaneously...
October 2, 2017: Circulation Research
https://www.readbyqxmd.com/read/28942951/the-algorithmic-performance-of-j-tpeak-for-drug-safety-clinical-trial
#9
Simon C Chien, Richard E Gregg
INTRODUCTION: The interval from J-point to T-wave peak (JTp) in ECG is a new biomarker able to identify drugs that prolong the QT interval but have different ion channel effects. If JTp is not prolonged, the prolonged QT may be associated with multi ion channel block that may have low torsade de pointes risk. From the automatic ECG measurement perspective, accurate and repeatable measurement of JTp involves different challenges than QT. We evaluated algorithm performance and JTp challenges using the Philips DXL diagnostic 12/16/18-lead algorithm...
August 15, 2017: Journal of Electrocardiology
https://www.readbyqxmd.com/read/28879040/comparison-of-effects-between-calcium-channel-blocker-and-diuretics-in-combination-with-angiotensin-ii-receptor-blocker-on-24-h-central-blood-pressure-and-vascular-hemodynamic-parameters-in-hypertensive-patients-study-design-for-a-multicenter-double-blinded
#10
Gyu Chul Oh, Hae-Young Lee, Wook Jin Chung, Ho-Joong Youn, Eun-Joo Cho, Ki-Chul Sung, Shung Chull Chae, Byung-Su Yoo, Chang Gyu Park, Soon Jun Hong, Young Kwon Kim, Taek-Jong Hong, Dong-Ju Choi, Min Su Hyun, Jong Won Ha, Young Jo Kim, Youngkeun Ahn, Myeong Chan Cho, Soon-Gil Kim, Jinho Shin, Sungha Park, Il-Suk Sohn, Chong-Jin Kim
BACKGROUND: Hypertension is a risk factor for coronary heart disease and stroke, and is one of the leading causes of death. Although over a billion people are affected worldwide, only half of them receive adequate treatment. Current guidelines on antihypertensive treatment recommend combination therapy for patients not responding to monotherapy, but as the number of pills increase, patient compliance tends to decrease. As a result, fixed-dose combination drugs with different antihypertensive agents have been developed and widely used in recent years...
2017: Clinical Hypertension
https://www.readbyqxmd.com/read/28864150/standard-and-strain-measurements-by-echocardiography-detect-early-overloaded-right-ventricular-dysfunction-validation-against-hemodynamic-and-myocyte-contractility-changes-in-a-large-animal-model
#11
Amir Hodzic, Pierre Bobin, Delphine Mika, Mohamed Ly, Florence Lefebvre, Patrick Lechêne, Emmanuel Le Bret, Elodie Gouadon, Mathieu Coblence, Grégoire Vandecasteele, André Capderou, Jérôme Leroy, Catherine Rucker-Martin, Virginie Lambert
BACKGROUND: Early detection of right ventricular (RV) failure is required to improve the management of patients with congenital heart diseases. The aim of this study was to validate echocardiography for the early detection of overloaded RV dysfunction, compared with hemodynamic and myocyte contractility assessment. METHODS: Using a porcine model reproducing repaired tetralogy of Fallot, RV function was evaluated over 4 months using standard echocardiography and speckle-tracking compared with hemodynamic parameters (conductance catheter)...
August 29, 2017: Journal of the American Society of Echocardiography
https://www.readbyqxmd.com/read/28823052/sensitivity-analysis-of-ventricular-activation-and-electrocardiogram-in-tailored-models-of-heart-failure-patients
#12
C Sánchez, G D'Ambrosio, F Maffessanti, E G Caiani, F W Prinzen, R Krause, A Auricchio, M Potse
Cardiac resynchronization therapy is not effective in a variable proportion of heart failure patients. An accurate knowledge of each patient's electroanatomical features could be helpful to determine the most appropriate treatment. The goal of this study was to analyze and quantify the sensitivity of left ventricular (LV) activation and the electrocardiogram (ECG) to changes in 39 parameters used to tune realistic anatomical-electrophysiological models of the heart. Electrical activity in the ventricles was simulated using a reaction-diffusion equation...
August 19, 2017: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/28757442/endothelin-receptor-mediated-ca-2-signaling-in-coronary-arteries-after-experimentally-induced-ischemia-reperfusion-injury-in-rat
#13
Sarah Brøgger Kristiansen, Kristian A Haanes, Majid Sheykhzade, Lars Edvinsson
BACKGROUND: Acute myocardial infarction is one of the leading causes of death. It is caused by a blockage of a coronary artery leading to reduced blood flow to the myocardium and hence ischemic damage. In addition, a second wave of damage after the flow has been restored, named reperfusion injury greatly exacerbate the damage. For the latter, no medical treatment exist. In this study the aim was to characterize Ca(2+) sensitivity in coronary arteries following experimental ischemia/reperfusion injury...
October 2017: Journal of Molecular and Cellular Cardiology
https://www.readbyqxmd.com/read/28670363/verapamil-suppresses-cardiac-alternans-and-ventricular-arrhythmias-in-acute-myocardial-ischemia-via-ryanodine-receptor-inhibition
#14
Yu-Lei Deng, Jun-Yan Zhao, Ji-Hua Yao, Qiang Tang, Le Zhang, Hong-Lian Zhou, Cun-Tai Zhang, Jia-Gao Lv, Xiao-Qing Quan
T-wave alternans (TWA) is a potent arrhythmia substrate under the conditions of acute myocardial ischemia. Abnormal intracellular calcium cycling contributes to the genesis of cardiac alternans. Ryanodine receptor (RyR) is a pivotal Ca(2+) cycling protein central to Ca(2+) signaling in the heart. Here, we investigated the potential role of RyR in cardiac alternans and ventricular arrhythmias in acute myocardial ischemia. Transmembrane action potentials were simultaneously recorded from epicardium and endocardium together with a transmural ECG and isometric contraction force in the arterially perfused left ventricular wedge preparations...
2017: American Journal of Translational Research
https://www.readbyqxmd.com/read/28611919/markers-of-arterial-stiffness-in-a-sample-of-lebanese-subjects-with-grade-i-essential-hypertension
#15
Samir Mallat, Abdo Jurjus, Tarek Bou Assi, Alice Jurjus, Ali Shams, Skye El Sayegh, Adel Berbari
OBJECTIVES: Arterial stiffness is becoming a major global condition associated with an increased risk of cardiovascular problems and death. Several markers have been linked to arterial stiffness. METHODS: To determine and evaluate these relations, anthropometric parameters (weight, height, and pulse rate), biochemical profile, and central and peripheral indices of arterial function were measured in 114 Lebanese subjects with Grade I essential hypertension. RESULTS: Age was associated with a higher pulse wave velocity (p = ...
2017: SAGE Open Medicine
https://www.readbyqxmd.com/read/28586374/nocturnal-leg-cramps-prevalence-and-associations-with-demographics-sleep-disturbance-symptoms-medical-conditions-and-cardiometabolic-risk-factors
#16
Michael A Grandner, John W Winkelman
BACKGROUND: Nocturnal leg cramps (NLC) are common and poorly understood. OBJECTIVE: To determine the prevalence of NLC and associations with cardiometabolic, sleep, and behavioral risk factors in the US population. DESIGN: Cross-sectional epidemiology. PARTICIPANTS: National Health and Nutrition Examination Survey, 2005-2006 and 2007-2008 waves. MAIN OUTCOME(S) AND MEASURE(S): NLC were assessed with, "In the past month, how often did you have leg cramps while trying to sleep?" Responses were categorized as None, Mild, or Moderate-Severe...
2017: PloS One
https://www.readbyqxmd.com/read/28522367/qrs-t-wave-and-calcium-alternans-in-a-type-i-diabetic-mouse-model-for-spontaneous-postmyocardial-infarction-ventricular-tachycardia-a-mechanism-for-the-antiarrhythmic-effect-of-statins
#17
Hongwei Jin, Charles M Welzig, Mark Aronovitz, Farzad Noubary, Robert Blanton, Bo Wang, Mohammad Rajab, Alfred Albano, Mark S Link, Sami F Noujaim, Ho-Jin Park, Jonas B Galper
BACKGROUND: The incidence of sudden arrhythmic death is markedly increased in diabetics. OBJECTIVE: The purpose of this study was to develop a mouse model for postmyocardial infarction (post-MI) ventricular tachycardia (VT) in the diabetic heart and determine the mechanism of an antiarrhythmic effect of statins. METHODS: ECG transmitters were implanted in wild-type (WT), placebo, and pravastatin-treated type I diabetic Akita mice. MIs were induced by coronary ligation, and Ca2+ transients were studied by optical mapping, and Ca2+ transients and sparks in left ventricular myocytes (VM) by the Ionoptix system and confocal microscopy...
September 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/28456163/varieties-of-reentrant-dynamics
#18
Lucas Campanari, Min Ju You, Peter Langfield, Leon Glass, Alvin Shrier
Experiments were carried out in monolayer tissue cultures of embryonic chick heart cells imaged using a calcium sensitive fluorescent dye. The cells were grown in annular geometries and in annular geometries with an isthmus connecting antipodal region of the annulus. We observed a large number of spatially different patterns of propagation consisting of one or more circulating waves. As well, we also observed rhythms in which rotors embedded in the annuli generated propagating pulses. These results demonstrate that many different patterns of excitation can be present in cardiac tissue with simple geometries...
April 2017: Chaos
https://www.readbyqxmd.com/read/28443950/chronic-kidney-disease-determinants-of-progression-and-cardiovascular-risk-progredir-cohort-study-design-and-methods
#19
Maria Alice Muniz Domingos, Alessandra Carvalho Goulart, Paulo Andrade Lotufo, Isabela Judith Martins Benseñor, Silvia Maria de Oliveira Titan
CONTEXT AND OBJECTIVE: Chronic kidney disease (CKD) has become an important public health issue. The socioeconomic burden of renal replacement therapy (RRT) is very high, as is CKD-related cardiovascular mortality and morbidity. Preventive and therapeutic measures only have modest impact and more research is needed. Few cohort studies have been conducted on populations with CKD. Our aim was to establish a cohort that would include more advanced forms of CKD (stages 3 and 4). Data collection was focused on renal and cardiovascular parameters...
March 2017: São Paulo Medical Journal, Revista Paulista de Medicina
https://www.readbyqxmd.com/read/28423119/importance-of-serca2a-on-early-isolated-diastolic-dysfunction-induced-by-supravalvular-aortic-stenosis-in-rats
#20
C F S M P Silveira, D H S Campos, P P Freire, A F Deus, K Okoshi, C R Padovani, A C Cicogna
Cardiac remodeling is defined as changes in shape and function of the heart in response to aggression (pressure overload). The sarcoplasmic reticulum calcium ATPase cardiac isoform 2a (SERCA2a) is a known factor that influences function. A wide spectrum of studies report a decrease in SERCA2a in heart failure, but none evaluate it's the role in early isolated diastolic dysfunction in supravalvular aortic stenosis (AoS). Our hypothesis was that SERCA2a participates in such dysfunction. Thirty-day-old male Wistar rats (60-80 g) were divided into AoS and Sham groups, which were submitted to surgery with or without aorta clipping, respectively...
April 13, 2017: Brazilian Journal of Medical and Biological Research, Revista Brasileira de Pesquisas Médicas e Biológicas
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