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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
#1
Hsiang-Ting Ho, Senthil Thambidorai, Björn C Knollmann, George E Billman, Sandor Györke, Anuradha Kalyanasundaram
BACKGROUND: Long-term aerobic exercise (EX) alters autonomic balance which may not be favorable in heart rate (HR) dependent arrhythmic diseases including Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) due to preexisting bradycardia and increased sensitivity to parasympathetic stimulation. OBJECTIVE: The purpose of this study was to determine if 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 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
#2
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, J Andrew Wasserstrom
Aims: Abnormal intracellular Ca 2+ cycling contributes to triggered activity and arrhythmias in the heart. We investigated the properties and underlying mechanisms for systolic triggered Ca 2+ waves in left atria from normal and failing dog hearts. Methods and Results: Intracellular Ca 2+ 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), Ca 2+ waves developed during rapid pacing at rates ≥ 3...
August 29, 2017: Cardiovascular Research
https://www.readbyqxmd.com/read/28970285/calcium-dependent-arrhythmogenic-foci-created-by-weakly-coupled-myocytes-in-the-failing-heart
#3
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
#4
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
#5
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
#6
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
#7
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
#8
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...
July 27, 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
#9
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
#10
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
#11
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
#12
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 Ca(2+) transients were studied by optical mapping, and Ca(2+) 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
#13
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
#14
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
#15
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
https://www.readbyqxmd.com/read/28213506/role-of-apamin-sensitive-calcium-activated-small-conductance-potassium-currents-on-the-mechanisms-of-ventricular-fibrillation-in-pacing-induced-failing-rabbit-hearts
#16
Dechun Yin, Yu-Cheng Hsieh, Wei-Chung Tsai, Adonis Zhi-Yang Wu, Zhaolei Jiang, Yi-Hsin Chan, Dongzhu Xu, Na Yang, Changyu Shen, Zhenhui Chen, Shien-Fong Lin, Peng-Sheng Chen, Thomas H Everett
BACKGROUND: Ventricular fibrillation (VF) during heart failure is characterized by stable reentrant spiral waves (rotors). Apamin-sensitive small-conductance calcium-activated potassium currents (IKAS) are heterogeneously upregulated in failing hearts. We hypothesized that IKAS influences the location and stability of rotors during VF. METHODS AND RESULTS: Optical mapping was performed on 9 rabbit hearts with pacing-induced heart failure. The epicardial right ventricular and left ventricular surfaces were simultaneously mapped in a Langendorff preparation...
February 2017: Circulation. Arrhythmia and Electrophysiology
https://www.readbyqxmd.com/read/28209766/glycosylated-chromogranin-a-in-heart-failure-implications-for-processing-and-cardiomyocyte-calcium-homeostasis
#17
Anett Hellebø Ottesen, Cathrine R Carlson, William E Louch, Mai Britt Dahl, Ragnhild A Sandbu, Rune Forstrøm Johansen, Hilde Jarstadmarken, Magnar Bjørås, Arne Didrik Høiseth, Jon Brynildsen, Ivar Sjaastad, Mats Stridsberg, Torbjørn Omland, Geir Christensen, Helge Røsjø
BACKGROUND: Chromogranin A (CgA) levels have previously been found to predict mortality in heart failure (HF), but currently no information is available regarding CgA processing in HF and whether the CgA fragment catestatin (CST) may directly influence cardiomyocyte function. METHODS AND RESULTS: CgA processing was characterized in postinfarction HF mice and in patients with acute HF, and the functional role of CST was explored in experimental models. Myocardial biopsies from HF, but not sham-operated mice, demonstrated high molecular weight CgA bands...
February 2017: Circulation. Heart Failure
https://www.readbyqxmd.com/read/28169003/increased-calcium-leak-associated-with-reduced-calsequestrin-expression-in-hyperthyroid-cardiomyocytes
#18
David R de Alba-Aguayo, Natalia Pavón, Martha Mercado-Morales, Miyamin Miranda-Saturnino, Mavil López-Casamichana, Agustin Guerrero-Hernández, Angelica Rueda
INTRODUCTION: Calcium (Ca(2+)) leak during cardiac diastole is chiefly mediated by intracellular Ca(2+) channel/Ryanodine Receptors. Increased diastolic Ca(2+) leak has been proposed as the mechanism underlying the appearance of hereditary arrhythmias. However, little is known about alterations in diastolic Ca(2+) leak and the specific roles played by key intracellular Ca(2+)-handling proteins in hyperthyroidism, a known arrhythmogenic condition. AIM: We sought to determine whether there were modifications in diastolic Ca(2+) leak, based on the recording of Ca(2+) sparks and Ca(2+) waves; we also investigated changes in the expression and activity of key Ca(2+) handling proteins, including ryanodine receptors, Sarco-Endoplasmic Reticulum Ca(2+) ATPase pump and calsequestrin in isolated left-ventricular cardiomyocytes isolated from hyperthyroid rats...
January 23, 2017: Cell Calcium
https://www.readbyqxmd.com/read/28087911/-aortic-stiffness-and-its-influencing-factors-in-patients-with-chronic-kidney-disease
#19
Binxian Ye, Li Zhao, Wei Shen, Yan Ren, Bo Lin, Maosheng Chen, Junda Tang, Xinxin Jiang, Yiwen Li, Qiang He
Objective: To investigate the changes of aortic stiffness and its influencing factors in patients with chronic kidney diseases (CKD). Methods: Eightyfour patients with CKD from Department of Nephrology, Zhejiang Provincial People's Hospital were divided into the dialysis group (CKD stage 5, n=48) and non-dialysis group (CKD stage 3-5, n=36). Clinical data, biochemical parameters and echocardiography findings were collected. SphygmoCor pulse wave analysis system was used to obtain pulse wave analysis (PWA) parameters including central aortic systolic blood pressure (CSP), central pulse pressure (CPP), augmented pressure (AP), augmentation index (AIX), and heart rate 75-adjusted augmentation index (HR75AIX)...
May 25, 2016: Zhejiang da Xue Xue Bao. Yi Xue Ban, Journal of Zhejiang University. Medical Sciences
https://www.readbyqxmd.com/read/27773880/high-calcium-exposure-to-frog-heart-a-simple-model-representing-hypercalcemia-induced-ecg-abnormalities
#20
Itsuro Kazama
By simply adding a high concentration of calcium solution to the surface of the bullfrog heart, we reproduced electrocardiogram (ECG) abnormalities representing those observed in hypercalcemia, such as Osborn waves and shortening of the QT interval. The rise in extracellular calcium concentration may have activated the outward potassium currents during phase 3 of the action potential, and thus decreased its duration. In addition to the known decrease in the duration of phase 2, such changes in phase 3 were also likely to contribute to the shortening of the QT interval...
January 20, 2017: Journal of Veterinary Medical Science
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