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https://www.readbyqxmd.com/read/27878490/cardiac-body-surface-potentials-in-rats-with-experimental-pulmonary-hypertension-during-ventricular-depolarization
#1
O V Suslonova, S L Smirnova, I M Roshchevskaya
The spatial and the amplitude-temporal parameters of cardiac body surface potentials were examined in female Wistar rats with experimental pulmonary hypertension during ventricular depolarization. The cardiac body surface potentials have been led from 64 subcutaneous electrodes evenly distributed across the chest surface prior to and 4 weeks after subcutaneous injection of a single dose of monocrotaline (60 mg/kg). Right ventricular hypertrophy and electrophysiological remodeling of the heart developed in rats with experimental pulmonary hypertension in 4 weeks after monocrotaline injection; these changes led to a significant increase in amplitude and temporal characteristics of the cardioelectric field on the body surface in comparison with the initial state...
November 22, 2016: Bulletin of Experimental Biology and Medicine
https://www.readbyqxmd.com/read/27833567/myofibroblasts-electrotonically-coupled-to-cardiomyocytes-alter-conduction-insights-at-the-cellular-level-from-a-detailed-in-silico-tissue-structure-model
#2
Florian Jousset, Ange Maguy, Stephan Rohr, Jan P Kucera
Fibrotic myocardial remodeling is typically accompanied by the appearance of myofibroblasts (MFBs). In vitro, MFBs were shown to slow conduction and precipitate ectopic activity following gap junctional coupling to cardiomyocytes (CMCs). To gain further mechanistic insights into this arrhythmogenic MFB-CMC crosstalk, we performed numerical simulations in cell-based high-resolution two-dimensional tissue models that replicated experimental conditions. Cell dimensions were determined using confocal microscopy of single and co-cultured neonatal rat ventricular CMCs and MFBs...
2016: Frontiers in Physiology
https://www.readbyqxmd.com/read/27815365/xanthohumol-modulates-calcium-signaling-in-rat-ventricular-myocytes-possible-antiarrhythmic-properties
#3
Juan Jose Arnaiz-Cot, Lars Cleemann, Martin Morad
Cardiac arrhythmia is a major cause of mortality in cardiovascular pathologies. A host of drugs targeted to sarcolemmal Na(+), Ca(2+), and K(+) channels have had limited success clinically. Recently, Ca(2+) signaling has been target of pharmacotherapy based on finding that leaky ryanodine receptors elevate local Ca(2+) concentrations causing membrane depolarizations that trigger arrhythmias. Here we report that xanthohumol, an antioxidant extracted from hops and showing therapeutic effects in other pathologies, may have antiarrhythmic properties by stabilizing ryanodine receptor's activity...
November 4, 2016: Journal of Pharmacology and Experimental Therapeutics
https://www.readbyqxmd.com/read/27815173/stable-gastric-pentadecapeptide-bpc-157-and-bupivacaine
#4
Gordana Zivanovic-Posilovic, Diana Balenovic, Ivan Barisic, Dean Strinic, Vasilije Stambolija, Mario Udovicic, Sandra Uzun, Domagoj Drmic, Josipa Vlainic, Martina Lovric Bencic, Aleksandra Sindic, Sven Seiwerth, Predrag Sikiric
Bupivacaine toxicity following accidental overdose still lacks therapeutic solution. However, there are major arguments for testing BPC 157 against bupivacaine toxicity in vivo in rats, in particular, and then finally, in vitro. These are: the lack of any known BPC 157 toxicity, a lifesaving effect via the mitigation of arrhythmias in rats underwent hyperkalemia or digitalis toxicity, the elimination of hyperkalemia and arrhythmias in rats underwent succinylcholine toxicity and finally, the reduction of potassium-induced depolarization in vitro (in HEK293 cells) in severe hyperkalemia...
December 15, 2016: European Journal of Pharmacology
https://www.readbyqxmd.com/read/27803673/electrophysiological-mechanisms-of-brugada-syndrome-insights-from-pre-clinical-and-clinical-studies
#5
REVIEW
Gary Tse, Tong Liu, Ka H C Li, Victoria Laxton, Yin W F Chan, Wendy Keung, Ronald A Li, Bryan P Yan
Brugada syndrome (BrS), is a primary electrical disorder predisposing affected individuals to sudden cardiac death via the development of ventricular tachycardia and fibrillation (VT/VF). Originally, BrS was linked to mutations in the SCN5A, which encodes for the cardiac Na(+) channel. To date, variants in 19 genes have been implicated in this condition, with 11, 5, 3, and 1 genes affecting the Na(+), K(+), Ca(2+), and funny currents, respectively. Diagnosis of BrS is based on ECG criteria of coved- or saddle-shaped ST segment elevation and/or T-wave inversion with or without drug challenge...
2016: Frontiers in Physiology
https://www.readbyqxmd.com/read/27793852/acute-exposure-to-progesterone-attenuates-cardiac-contraction-by-modifying-myofilament-calcium-sensitivity-in-the-female-mouse-heart
#6
Hirad A Feridooni, Jennifer K MacDonald, Anjali Ghimire, W Glen Pyle, Susan E Howlett
Acute application of progesterone attenuates cardiac contraction, although the underlying mechanisms are unclear. We investigated whether progesterone modified contraction in isolated ventricular myocytes and identified the Ca(2+) handling mechanisms involved in female C57BL/6 mice (6-9 mos; sodium pentobarbital anesthesia). Cells were field-stimulated (4 Hz; 37°C) and exposed to progesterone (0.001-10.0 μM) or vehicle (35 mins). Ca(2+) transients (fura-2) and cell shortening were recorded simultaneously...
October 28, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27771553/correction-of-impaired-calmodulin-binding-to-ryr2-as-a-novel-therapy-for-lethal-arrhythmia-in-the-pressure-overloaded-heart-failure
#7
Takayoshi Kato, Takeshi Yamamoto, Yoshihide Nakamura, Takuma Nanno, Go Fukui, Yoko Sufu, Yoriomi Hamada, Takako Maeda, Shigehiko Nishimura, Hironori Ishiguchi, Wakako Murakami, Masakazu Fukuda, Xiaojuan Xu, Akihiro Hino, Makoto Ono, Tetsuro Oda, Shinichi Okuda, Shigeki Kobayashi, Noritaka Koseki, Hiroyuki Kyushiki, Masafumi Yano
BACKGROUND: Calmodulin (CaM) is a key modulator of the channel gating function of the ryanodine receptor (RyR). OBJECTIVE: The purpose of this study was to investigate the pathogenic role of RyR-bound CaM in diastolic Ca(2+) leakage from the sarcoplasmic reticulum and arrhythmogenesis in pressure-overloaded heart failure. METHODS: Pressure overload was induced in 12-week-old mice by transverse aortic constriction (TAC) using a 27-gauge needle...
October 19, 2016: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/27764178/multi-country-evaluation-of-safety-of-dihydroartemisinin-piperaquine-post-licensure-in-african-public-hospitals-with-electrocardiograms
#8
Abdunoor M Kabanywanyi, Rita Baiden, Ali M Ali, Muhidin K Mahende, Bernhards R Ogutu, Abraham Oduro, Halidou Tinto, Margaret Gyapong, Ali Sie, Esperanca Sevene, Eusebio Macete, Seth Owusu-Agyei, Alex Adjei, Guillaume Compaoré, Innocent Valea, Isaac Osei, Abena Yawson, Martin Adjuik, Raymond Akparibo, Mwaka A Kakolwa, Salim Abdulla, Fred Binka
The antimalarial drug piperaquine is associated with delayed ventricular depolarization, causing prolonged QT interval (time taken for ventricular de-polarisation and re-polarisation). There is a lack of safety data regarding dihydroartemisinin/piperaquine (DHA/PPQ) for the treatment of uncomplicated malaria, which has limited its use. We created a platform where electrocardiograms (ECG) were performed in public hospitals for the safety assessment of DHA/PPQ, at baseline before the use of dihydroartemisinin/piperaquine (Eurartesim®), and on day 3 (before and after administration of the final dose) and day 7 post-administration...
2016: PloS One
https://www.readbyqxmd.com/read/27762288/the-effects-of-puerarin-on-rat-ventricular-myocytes-and-the-potential-mechanism
#9
Hao Xu, Manxi Zhao, Shenghui Liang, Quanshu Huang, Yunchuan Xiao, Liang Ye, Qinyi Wang, Longmei He, Lanxiang Ma, Hua Zhang, Li Zhang, Hui Jiang, Xiao Ke, Yuchun Gu
Puerarin, a known isoflavone, is commonly found as a Chinese herb medicine. It is widely used in China to treat cardiac diseases such as angina, cardiac infarction and arrhythmia. However, its cardioprotective mechanism remains unclear. In this study, puerarin significantly prolonged ventricular action potential duration (APD) with a dosage dependent manner in the micromolar range on isolated rat ventricular myocytes. However, submicromolar puerarin had no effect on resting membrane potential (RMP), action potential amplitude (APA) and maximal velocity of depolarization (Vmax) of action potential...
October 20, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27761157/current-topics-in-catecholaminergic-polymorphic-ventricular-tachycardia
#10
Naokata Sumitomo
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is induced by emotions or exercise in patients without organic heart disease and may be polymorphic or bidirectional in nature. The prognosis of CPVT is not good, and therefore prevention of sudden death is of utmost importance. Genetic variants of CPVT include RyR2, CASQ2, CALM2, TRD, and possibly KCNJ2 and ANK2 gene mutations. Hypotheses that suggest the causes of CPVT include weakened binding of FKBP12.6 and RyR2, a store overload-induced Ca(2+) release (SOICR), unzipping of intramolecular domain interactions in RyR2, and molecular and functional abnormalities caused by mutations in the CASQ2 gene...
October 2016: Journal of Arrhythmia
https://www.readbyqxmd.com/read/27753830/sy-03-3-overview-of-somatic-mutations-and-epigenetic-regulation-of-aldosterone-producing-adenoma-apa
#11
Satoshi Umemura
Primary aldosteronism (PA) is a heterogeneous group of disorders including both sporadic and familial forms (familial hyperaldosteronism type I, II and III). PA is the most frequent endocrine cause of secondary hypertension and associated with a higher rate of cardiovascular complications, compared with essential hypertension.Here I review the recent progress in understanding of the genetic and molecular mechanisms leading to autonomous aldosterone production in PA.Systematic screening detects primary aldosteronism in 5 to 10% of all patients with hypertension and in approximately 20% of patients with resistant hypertension...
September 2016: Journal of Hypertension
https://www.readbyqxmd.com/read/27753447/high-left-ventricular-lead-sensing-delay-predicts-qrs-narrowing-and-good-response-to-cardiac-resynchronization-therapy
#12
Onur Kaypakli, Mevlüt Koç, Gökhan Gözübüyük, Durmuş Yildiray Şahin
BACKGROUND: Cardiac resynchronization therapy (CRT) was shown to improve heart failure (HF) prognosis. But many patients do not benefit from CRT. Optimization of left ventricular (LV) lead position to the latest activated LV area is important to increase CRT response. We aimed to detect the relationship between LV lead sensing delay and echocardiographic and electrocardiographic response to CRT treatment. METHODS: We prospectively included 156 consecutive patients with HF diagnosis, QRS ≥ 120 ms, left bundle branch block, New York Heart Association II-IV, LV ejection fraction (LVEF) < 35%, and scheduled for CRT (100 male, 56 female; mean age 65...
October 18, 2016: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/27726057/recovery-of-renal-dysfunction-after-catheter-ablation-of-outflow-tract-ventricular-arrhythmias-in-patients-with-ventricular-premature-depolarization-mediated-cardiomyopathy
#13
Shingo Maeda, William W Chik, Jackson J Liang, Iosif Kelesidis, Ruben Casado Arroyo, Benjamin D'Souza, Mouhannad M Sadek, Daniele Muser, Fabien Squara, Deviprasad Venugopal, Pasquale Santangeli, David S Frankel, Erica S Zado, Francis E Marchlinski, David J Callans
PURPOSE: Frequent ventricular premature depolarizations (VPDs) may cause cardiomyopathy (VPDCM), which often improves after VPD suppression. This study aimed to evaluate whether ablation of outflow tract ventricular arrhythmias (OT VAs) in patients with VPDCM improves renal in addition to left ventricular (LV) function. METHODS: We retrospectively evaluated 153 patients with OT VAs and examined VPD burden and LV ejection fraction (LVEF), as well as estimated glomerular filtration rate (eGFR) pre- and post-ablation...
October 10, 2016: Journal of Interventional Cardiac Electrophysiology: An International Journal of Arrhythmias and Pacing
https://www.readbyqxmd.com/read/27723506/self-organizing-visualization-and-pattern-matching-of-vectorcardiographic-qrs-waveforms
#14
Hui Yang, Fabio Leonelli
QRS morphology is commonly used in the electrocardiographic diagnosis of ventricular depolarization such as left bundle branch block (LBBB) and ventricular septal infarction. We investigated whether pattern matching of QRS loops in the 3-dimensional vectorcardiogram (VCG) will improve the grouping of patients whose space-time electrical activity akin to each other, thereby assisting in clinical decision making. First, pattern dissimilarity of VCG QRS loops is qualitatively measured and characterized among patients, resulting in a 93×93 distance matrix of patient-to-patient dissimilarity...
September 28, 2016: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/27694214/dyssynchronous-calcium-removal-in-heart-failure-induced-atrial-remodeling
#15
F Hohendanner, J DeSantiago, F R Heinzel, L A Blatter
We tested the hypothesis that in atrial myocytes from a rabbit left ventricular heart failure (HF) model, spatial inhomogeneity and temporal dyssynchrony of Ca removal during excitation-contraction coupling together with increased Na/Ca exchange (NCX) activity generate a substrate for proarrhythmic Ca release. Ca removal occurs via Ca reuptake into the sarcoplasmic reticulum and extrusion via NCX exclusively in the cell periphery since rabbit atrial myocytes lack transverse tubules. Ca removal kinetics were assessed by the time constant τ of decay of local peripheral subsarcolemmal (SS) and central (CT) action potential (AP)-induced Ca transients (CaTs) recorded in confocal line scan mode (using Fluo-4)...
December 1, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27642883/sy-03-3-overview-of-somatic-mutations-and-epigenetic-regulation-of-aldosterone-producing-adenoma-apa
#16
Satoshi Umemura
Primary aldosteronism (PA) is a heterogeneous group of disorders including both sporadic and familial forms (familial hyperaldosteronism type I, II and III). PA is the most frequent endocrine cause of secondary hypertension and associated with a higher rate of cardiovascular complications, compared with essential hypertension.Here I review the recent progress in understanding of the genetic and molecular mechanisms leading to autonomous aldosterone production in PA.Systematic screening detects primary aldosteronism in 5 to 10% of all patients with hypertension and in approximately 20% of patients with resistant hypertension...
September 2016: Journal of Hypertension
https://www.readbyqxmd.com/read/27629507/pathogenesis-and-management-of-brugada-syndrome
#17
Juan Sieira, Gregory Dendramis, Pedro Brugada
Brugada syndrome is an inherited disease characterized by an increased risk of sudden cardiac death owing to ventricular arrhythmias in the absence of structural heart disease. Since the first description of the syndrome >20 years ago, considerable advances have been made in our understanding of the underlying mechanisms involved and the strategies to stratify at-risk patients. The development of repolarization-depolarization abnormalities in patients with Brugada syndrome can involve genetic alterations, abnormal neural crest cell migration, improper gap junctional communication, or connexome abnormalities...
September 15, 2016: Nature Reviews. Cardiology
https://www.readbyqxmd.com/read/27617859/optogenetic-defibrillation-terminates-ventricular-arrhythmia-in-mouse-hearts-and-human-simulations
#18
Tobias Bruegmann, Patrick M Boyle, Christoph C Vogt, Thomas V Karathanos, Hermenegild J Arevalo, Bernd K Fleischmann, Natalia A Trayanova, Philipp Sasse
Ventricular arrhythmias are among the most severe complications of heart disease and can result in sudden cardiac death. Patients at risk currently receive implantable defibrillators that deliver electrical shocks to terminate arrhythmias on demand. However, strong electrical shocks can damage the heart and cause severe pain. Therefore, we have tested optogenetic defibrillation using expression of the light-sensitive channel channelrhodopsin-2 (ChR2) in cardiac tissue. Epicardial illumination effectively terminated ventricular arrhythmias in hearts from transgenic mice and from WT mice after adeno-associated virus-based gene transfer of ChR2...
October 3, 2016: Journal of Clinical Investigation
https://www.readbyqxmd.com/read/27616994/reduced-sodium-current-in-the-lateral-ventricular-wall-induces-inferolateral-j-waves
#19
Veronique M F Meijborg, Mark Potse, Chantal E Conrath, Charly N W Belterman, Jacques M T De Bakker, Ruben Coronel
BACKGROUND: J-waves in inferolateral leads are associated with a higher risk for idiopathic ventricular fibrillation. We aimed to test potential mechanisms (depolarization or repolarization dependent) responsible for inferolateral J-waves. We hypothesized that inferolateral J-waves can be caused by regional delayed activation of myocardium that is activated late during normal conditions. METHODS: Computer simulations were performed to evaluate how J-point elevation is influenced by reducing sodium current conductivity (GNa), increasing transient outward current conductivity (Gto), or cellular uncoupling in three predefined ventricular regions (lateral, anterior, or septal)...
2016: Frontiers in Physiology
https://www.readbyqxmd.com/read/27616550/the-novel-h2s-donor-4-carboxyphenyl-isothiocyanate-promotes-cardioprotective-effects-against-ischemia-reperfusion-injury-through-activation-of-mitokatp-channels-and-reduction-of-oxidative-stress
#20
Lara Testai, Alice Marino, Ilaria Piano, Vincenzo Brancaleone, Kengo Tomita, Lorenzo Di Cesare Mannelli, Alma Martelli, Valentina Citi, Maria C Breschi, Roberto Levi, Claudia Gargini, Mariarosaria Bucci, Giuseppe Cirino, Carla Ghelardini, Vincenzo Calderone
The endogenous gasotransmitter hydrogen sulphide (H2S) is an important regulator of the cardiovascular system, particularly of myocardial function. Moreover, H2S exhibits cardioprotective activity against ischemia/reperfusion (I/R) or hypoxic injury, and is considered an important mediator of "ischemic preconditioning", through activation of mitochondrial potassium channels, reduction of oxidative stress, activation of the endogenous "anti-oxidant machinery" and limitation of inflammatory responses. Accordingly, H2S-donors, i...
September 9, 2016: Pharmacological Research: the Official Journal of the Italian Pharmacological Society
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