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https://www.readbyqxmd.com/read/29668881/hyperactive-ryanodine-receptors-in-human-heart-failure-and-ischemic-cardiomyopathy-reside-outside-of-couplons
#1
Eef Dries, Demetrio J Santiago, Guillaume Gilbert, Ilse Lenaerts, Bert Vandenberk, Chandan K Nagaraju, Daniel M Johnson, Patricia Holemans, H Llewelyn Roderick, Niall Macquaide, Piet Claus, Karin R Sipido
Aims: In ventricular myocytes from humans and large mammals, the transverse and axial tubular system (TATS) network is less extensive than in rodents with consequently a greater proportion of ryanodine receptors (RyRs) not coupled to this membrane system. TATS remodeling in heart failure (HF) and after myocardial infarction (MI) increases the fraction of non-coupled RyR. Here we investigate whether this remodeling alters the activity of coupled and non-coupled RyR sub-populations through changes in local signaling...
April 14, 2018: Cardiovascular Research
https://www.readbyqxmd.com/read/29626474/canstatin-modulates-l-type-calcium-channel-activity-in-rat-ventricular-cardiomyocytes
#2
Keisuke Imoto, Masaki Hirakawa, Muneyoshi Okada, Hideyuki Yamawaki
Excessive increase of cytosolic Ca2+ through the activation of L-type Ca2+ channels (LTCCs) via β adrenergic receptor induces apoptosis of cardiomyocytes. Canstatin, a cleaved fragment of collagen type IV α2 chain, is abundantly expressed in normal heart tissue. We previously reported that canstatin inhibits β adrenergic receptor-stimulated apoptosis in cardiomyoblasts. Here, we tested the hyposeis that canstatin regulates LTCCs activity in ventricular cardiomyocytes. Collagen type IV α2 chain (COL4A2) small interfering (si) RNA (for canstatin suppression) or control siRNA was injected via jugular vein in Wistar rats...
April 4, 2018: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/29589390/high-brachial-ankle-pulse-wave-velocity-as-a-marker-for-predicting-coronary-artery-stenosis-in-patients-with-type-2-diabetes
#3
Bo Hyun Kim, Jae Sik Jang, Yong Seop Kwon, June Hyung Kim, In Joo Kim, Chang Won Lee
BACKGROUND: We evaluated the ability of brachial ankle pulse wave velocity (baPWV) to predict coronary artery stenosis (CAS) in patients with type 2 diabetes, and compared the predictive power of baPWV to that of well-known cardiovascular disease (CVD) risk calculators. METHODS: The study group included 83 consecutive patients over 30 years old with type 2 diabetes who complained of vague chest discomfort. An automatic pulse waveform analyzer was used to measure baPWV...
March 2018: Endocrinology and Metabolism
https://www.readbyqxmd.com/read/29531576/quantitative-assessment-of-the-physiological-parameters-influencing-qt-interval-response-to-medication-application-of-computational-intelligence-tools
#4
Sebastian Polak, Barbara Wiśniowska, Aleksander Mendyk, Adam Pacławski, Jakub Szlęk
Human heart electrophysiology is complex biological phenomenon, which is indirectly assessed by the measured ECG signal. ECG trace is further analyzed to derive interpretable surrogates including QT interval, QRS complex, PR interval, and T wave morphology. QT interval and its modification are the most commonly used surrogates of the drug triggered arrhythmia, but it is known that the QT interval itself is determined by other nondrug related parameters, physiological and pathological. In the current study, we used the computational intelligence algorithms to analyze correlations between various simulated physiological parameters and QT interval...
2018: Computational and Mathematical Methods in Medicine
https://www.readbyqxmd.com/read/29466325/electromechanical-vortex-filaments-during-cardiac-fibrillation
#5
J Christoph, M Chebbok, C Richter, J Schröder-Schetelig, P Bittihn, S Stein, I Uzelac, F H Fenton, G Hasenfuß, R F Gilmour, S Luther
Self-organized dynamics of vortex-like rotating waves or scroll waves underlie complex spatial-temporal pattern formation in many excitable chemical and biological systems1-4 . In the heart, filament-like phase singularities5,6 associated with three-dimensional scroll waves8 are considered to be the organizing centers of life-threatening cardiac arrhythmias7-13 . The mechanisms underlying the onset, perpetuation, and control14-16 of electromechanical turbulence in the heart are inherently three-dimensional phenomena...
February 21, 2018: Nature
https://www.readbyqxmd.com/read/29408955/high-androgens-in-postmenopausal-women-and-the-risk-for-atherosclerosis-and-cardiovascular-disease-the-rotterdam-study
#6
Cindy Meun, Oscar H Franco, Klodian Dhana, Loes Jaspers, Taulant Muka, Yvonne Louwers, M Arfan Ikram, Bart C J M Fauser, Maryam Kavousi, Joop S E Laven
Context: Polycystic ovary syndrome (PCOS) is closely linked to hyperandrogenism. In PCOS, hyperandrogenism has been associated with metabolic disturbances which increase the risk for cardiovascular disease (CVD). Objective: To assess the association of high serum androgen levels, as a postmenopausal remnant of PCOS, with the prevalence of atherosclerosis and incidence of CVD in postmenopausal women. Design: The Rotterdam Study, a prospective population-based cohort study...
February 1, 2018: Journal of Clinical Endocrinology and Metabolism
https://www.readbyqxmd.com/read/29344379/changes-in-contractile-protein-expression-are-linked-to-ventricular-stiffness-in-infants-with-pulmonary-hypertension-or-right-ventricular-hypertrophy-due-to-congenital-heart-disease
#7
Andrew R Bond, Dominga Iacobazzi, Safa Abdul-Ghani, Mohammed Ghorbel, Kate Heesom, Mariangela Wilson, Christopher Gillett, Sarah J George, Massimo Caputo, Saadeh Suleiman, Robert M R Tulloh
Background: The right ventricle (RV) is not designed to sustain high pressure leading to failure. There are no current medications to help RV contraction, so further information is required on adaption of the RV to such hypertension. Methods: The Right Ventricle in Children (RVENCH) study assessed infants with congenital heart disease undergoing cardiac surgery with hypertensive RV. Clinical and echocardiographic data were recorded, and samples of RV were taken from matched infants, analysed for proteomics and compared between pathologies and with clinical and echocardiographic outcome data...
2018: Open Heart
https://www.readbyqxmd.com/read/29325977/role-of-apamin-sensitive-small-conductance-calcium-activated-potassium-currents-in-long-term-cardiac-memory-in-rabbits
#8
Dechun Yin, Mu Chen, Na Yang, Adonis Z Wu, Dongzhu Xu, Wei-Chung Tsai, Yuan Yuan, Zhipeng Tian, Yi-Hsin Chan, Changyu Shen, Zhenhui Chen, Shien-Fong Lin, James N Weiss, Peng-Sheng Chen, Thomas H Everett
BACKGROUND: Apamin-sensitive small conductance calcium-activated K current (IKAS ) is up-regulated during ventricular pacing and masks short-term cardiac memory (CM). OBJECTIVE: The purpose of this study was to determine the role of IKAS in long-term CM. METHODS: CM was created with 3-5 weeks of ventricular pacing and defined by a flat or inverted T wave off pacing. Epicardial optical mapping was performed in both paced and normal ventricles...
January 8, 2018: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/29217881/reduced-baroreflex-sensitivity-decreased-heart-rate-variability-with-increased-arterial-stiffness-in-predialysis
#9
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
#10
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
#11
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
#12
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
#13
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/accentuated-vagal-antagonism-paradoxically-increases-ryanodine-receptor-calcium-leak-in-long-term-exercised-calsequestrin2-knockout-mice
#14
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) Ca2+ 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
#15
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
#16
Di Lang, Daisuke Sato, Yanyan Jiang, Kenneth S Ginsburg, Crystal M Ripplinger, Donald M Bers
RATIONALE: Intercellular uncoupling and Ca2+ (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] simultaneously...
December 8, 2017: Circulation Research
https://www.readbyqxmd.com/read/28942951/the-algorithmic-performance-of-j-tpeak-for-drug-safety-clinical-trial
#17
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
#18
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
#19
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
#20
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
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