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Sinus bradycardia

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https://www.readbyqxmd.com/read/28917552/crispr-correction-of-the-prkag2-gene-mutation-in-the-patient-s-ipsc-derived-cardiomyocytes-eliminates-the-electrophysiological-and-structural-abnormalities
#1
Ronen Ben Jehuda, Binyamin Eisen, Yuval Shemer, Lucy N Mekies, Agnes Szantai, Irina Reiter, Huanhuan Cui, Kaomei Guan, Shiraz Haron-Khun, Dov Freimark, Silke R Sperling, Mihaela Gherghiceanu, Michael Arad, Ofer Binah
BACKGROUND: Mutations in the PRKAG2 gene encoding the γ-subunit of adenosine monophosphate-kinase (AMPK) cause hypertrophic cardiomyopathy (HCM) and familial-Wolff-Parkinson-White syndrome (WPW). Patients carrying the R302Q mutation in PRKAG2 present sinus bradycardia, escape rhythms, ventricular pre-excitation, supraventricular tachycardia and atrioventricular block. This mutation affects AMPK activity and increases glycogen storage in cardiomyocytes. The link between glycogen storage, WPW, HCM and arrhythmias remains unknown...
September 13, 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/28905113/influence-of-increased-heart-rate-and-aortic-pressure-on-resting-indices-of-functional-coronary-stenosis-severity
#2
Lorena Casadonte, Bart-Jan Verhoeff, Jan J Piek, Ed VanBavel, Jos A E Spaan, Maria Siebes
Baseline assessment of functional stenosis severity has been proposed as a practical alternative to hyperemic indices. However, intact autoregulation mechanisms may affect intracoronary hemodynamics. The aim of this study was to investigate the effect of changes in aortic pressure (Pa) and heart rate (HR) on baseline coronary hemodynamics and functional stenosis assessment. In 15 patients (55 ± 3% diameter stenosis) Pa, intracoronary pressure (Pd) and flow velocity were obtained at control, and during atrial pacing at 120 bpm, increased Pa (+30 mmHg) with intravenous phenylephrine (PE), and elevated Pa while pacing at sinus heart rate (PE + sHR)...
September 13, 2017: Basic Research in Cardiology
https://www.readbyqxmd.com/read/28900547/chagas-cardiomyopathy-presenting-as-symptomatic-bradycardia-an-underappreciated-emerging-public-health-problem-in-the-united-states
#3
Richard Jesse Durrance, Tofura Ullah, Zulekha Atif, William Frumkin, Kaushik Doshi
Chagas cardiomyopathy (CCM) is traditionally considered a disease restricted to areas of endemicity. However, an estimated 300,000 people living in the United States today have CCM, of which its majority is undiagnosed. We present a case of CCM acquired in an endemic area and detected in its early stage. A 42-year-old El Salvadoran woman presented with recurrent chest pain and syncopal episodes. Significant family history includes a sister in El Salvador who also began suffering similar episodes. Physical exam and ancillary studies were only remarkable for sinus bradycardia...
2017: Case Reports in Cardiology
https://www.readbyqxmd.com/read/28899000/rhoa-rock-signalling-is-necessary-for-lateralization-and-differentiation-of-the-developing-sinoatrial-node
#4
Rebecca Vicente-Steijn, Tim P Kelder, Leon G Tertoolen, Lambertus J Wisse, Daniël A Pijnappels, Robert E Poelmann, Martin J Schalij, Marco C deRuiter, Adriana C Gittenberger-de Groot, Monique R M Jongbloed
Aims: RHOA-ROCK signalling regulates cell migration, proliferation, differentiation, and transcription. RHOA is expressed in the developing cardiac conduction system in chicken and mice. In early development, the entire sinus venosus myocardium, including both the transient left-sided and the definitive sinoatrial node (SAN), has pacemaker potential. Later, pacemaker potential is restricted to the right-sided SAN. Disruption of RHOA expression in adult mice causes arrhythmias including bradycardia and atrial fibrillation, the mechanism of which is unknown but presumed to affect the SAN...
August 1, 2017: Cardiovascular Research
https://www.readbyqxmd.com/read/28891553/hyperthyroidism-and-sick-sinus-syndrome-a-rare-but-challenging-association-a-study-of-three-cases
#5
M Tudoran, C Tudoran
Hyperthyroidism is usually associated with sinus tachycardia or supraventricular tachyarrhythmias, but rarely with dysfunction of the sinus node or other conduction disturbances. Evidence of bradyarrhythmia in patients with hyperthyroidism is clinically relevant, but the fact that several drugs with negative chronotropic effects (beta-blockers and calcium channel antagonists) are frequently used in the management of these patients must be taken into account. In the presence of sick sinus syndrome (SSS) or other conductance disturbances, therapy with agents that delay the activity of sinus node or atrioventricular conduction can lead to extreme bradycardia with syncope...
August 2017: Nigerian Journal of Clinical Practice
https://www.readbyqxmd.com/read/28866703/clinical-judgement-perplexed-by-initially-undisclosed-use-of-herbal-medicine-and-unexpected-cross-reactivity-of-immunoassay
#6
K T Liu, C W Lee
We report a case of symptomatic bradycardia caused by consumption of a Chinese herbal medicine which was initially undisclosed to the attending emergency physician. The scientific name of the herb is Panax japonicus. Electrocardiogram revealed sinus bradycardia. Laboratory tests were normal except for the detection of a high serum digoxin level. Further interrogation of the patient eventually disclosed ingestion of the herb which, however, did not contain any digoxin. Other active ingredients in the herb include various types of ginsenoside...
August 2017: Malaysian Journal of Pathology
https://www.readbyqxmd.com/read/28845312/symptomatic-long-pauses-and-bradycardia-due-to-massive-multinodular-goiter
#7
Amrish Deshmukh, Cevher Ozcan
Sinus node dysfunction with symptomatic bradycardia or chronotropic incompetence is generally an indication for pacemaker implantation. However, in patients with symptomatic sinus bradycardia, the identification and treatment of underlying pathologies may avoid the need for permanent pacemaker implantation. We present a case of carotid sinus syndrome and severe obstructive sleep apnea due to a massive multinodular goiter in a patient who presented with recurrent sinus pauses and syncope. The patient was managed without pacemaker implantation but instead with thyroidectomy resulting in decompression of the carotid sinus and airway and resolution of bradycardic episodes...
2017: Case Reports in Cardiology
https://www.readbyqxmd.com/read/28830271/the-acute-toxic-effects-of-silver-nanoparticles-on-myocardial-transmembrane-potential-ina-and-ik1-channels-and-heart-rhythm-in-mice
#8
Cai-Xia Lin, Su-Yu Yang, Jing-Li Gu, Jie Meng, Hai-Yan Xu, Ji-Min Cao
This study focused on the potential toxicity of silver nanoparticles (AgNPs) on cardiac electrophysiology which is rarely investigated. We found that AgNPs (10(-9)-10(-6 )g/ml) concentration-dependently depolarized the resting potential, diminished the action potential, and finally led to loss of excitability in mice cardiac papillary muscle cells in vitro. In cultured neonatal mice cardiomyocytes, AgNPs (10(-9)-10(-7 )g/ml) concentration-dependently decreased the Na(+) currents (INa), accelerated the activation, and delayed the inactivation and recovery of Na(+) channels from inactivation within 5 min...
August 23, 2017: Nanotoxicology
https://www.readbyqxmd.com/read/28821541/targeting-mir-423-5p-reverses-exercise-training-induced-hcn4-channel-remodeling-and-sinus-bradycardia
#9
Alicia D'Souza, Charles M Pearman, Yanwen Wang, Shu Nakao, Sunil Jit R Logantha, Charlotte Cox, Hayley J Bennett, Yu Zhang, Anne Berit Johnsen, Nora Linscheid, Pi C Poulsen, Jonathan Elliott, Jessica Coulson, Jamie S McPhee, Abigail C Robertson, Paula A da Costa Martins, Ashraf Kitmitto, Ulrik Wisloff, Elizabeth J Cartwright, Oliver Monfredi, Alicia Lundby, Halina Dobrzynski, Delvac Oceandy, Gwilym M Morris, Mark R Boyett
Rationale: Downregulation of the pacemaking ion channel, HCN4, and the corresponding ionic current, If, underlies exercise training-induced sinus bradycardia in rodents. If this occurs in humans, it could explain the increased incidence of bradyarrhythmias in veteran athletes and it will be important to understand the underlying processes. Objective: To test the role of HCN4 in the training-induced bradycardia in human athletes and investigate the role of micro-RNAs (miRs) in the repression of HCN4. Methods and Results: As in rodents, the intrinsic heart rate was significantly lower in human athletes than non-athletes and in all subjects the rate-lowering effect of the HCN selective blocker, ivabradine, was significantly correlated with the intrinsic heart rate, consistent with HCN repression in athletes...
August 17, 2017: Circulation Research
https://www.readbyqxmd.com/read/28807352/unusual-digoxin-toxicity-with-myocardial-injury
#10
Mohamad Jihad Mansour, Maher Kalaoui, Elie Chammas, Omar Hamoui, Tarek Fawaz, Wael A AlJaroudi
A 38-year-old healthy male presented with vomiting and profuse diarrhea, associated with blurry and yellow coloration of the vision (xanthopsia). Laboratory workup was unremarkable, except for hyperkalemia (K 5.2 mEq/L) and mildly elevated troponin level 0.11 ng/mL (cut-off value 0.08). An electrocardiogram showed sinus bradycardia with deep scooping of the T waves. Although the patient denied intake of any drugs, herbs, consumption of plants, a digoxin level was drawn and was significantly elevated >5ng/mL (therapeutic range 0...
July 12, 2017: Journal of Electrocardiology
https://www.readbyqxmd.com/read/28803741/the-cardiovascular-toxicity-of-triadimefon-in-early-life-stage-of-zebrafish-and-potential-implications-to-human-health
#11
Hong-Cui Liu, Tian-Yi Chu, Li-Li Chen, Wen-Jun Gui, Guo-Nian Zhu
The health risk of triadimefon (TF) to cardiovascular system of human is still unclear, especially to pesticide suicides population, occupational population (farmers, retailers and pharmaceutical workers), and special population (young children and infants, pregnant women, older people, and those with compromised immune systems) who are at a greater risk. Therefore, firstly we explored the toxic effects and possible mechanism of cardiovascular toxicity induced by TF using zebrafish model. Zebrafish at stage of 48 h post fertilization (hpf) exposed to TF for 24 h exhibited morphological malformations which were further confirmed by histopathologic examination, including pericardial edema, circulation abnormalities, serious venous thrombosis and increased distance between the sinus venosus (SV) and bulbus arteriosus (BA) regions of the heart...
August 10, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28803248/a-functional-assay-for-sick-sinus-syndrome-genetic-variants
#12
Chuanchau J Jou, Cammon B Arrington, Spencer Barnett, Jiaxiang Shen, Scott Cho, Xiaoming Sheng, Patrick C McCullagh, Neil E Bowles, Chase M Pribble, Elizabeth V Saarel, Thomas A Pilcher, Susan P Etheridge, Martin Tristani-Firouzi
BACKGROUND/AIMS: Congenital Sick Sinus Syndrome (SSS) is a disorder associated with sudden cardiac death due to severe bradycardia and prolonged pauses. Mutations in HCN4, the gene encoding inward Na+/K+ current (If), have been described as a cause of congenital SSS. The objective of this study is to develop an SSS model in embryonic zebrafish, and use zebrafish as a moderate-throughput assay to functionally characterize HCN4 variants. METHODS: To determine the function of hcn4 in zebrafish, embryos were either bathed in the If -specific blocker (ZD-7288), or endogenous hcn4 expression was knocked down using splice-blocking morpholinos...
August 11, 2017: Cellular Physiology and Biochemistry
https://www.readbyqxmd.com/read/28802598/effect-of-parecoxib-sodium-pretreatment-combined-with-dexmedetomidine-on-early-postoperative-cognitive-dysfunction-in-elderly-patients-after-shoulder-arthroscopy-a-randomized-double-blinded-controlled-trial
#13
Jian Lu, Gang Chen, Hongmei Zhou, Qinghe Zhou, Zhipeng Zhu, Cheng Wu
STUDY OBJECTIVE: To evaluate effect of parecoxib sodium pretreatment combined with dexmedetomidine on early postoperative cognitive dysfunction in elderly patients after shoulder arthroscopy. DESIGN: Randomized, double-blind study. SETTING: University-affiliated teaching hospital. PATIENTS: One hundred and fifty-two elderly patients scheduled for shoulder arthroscopy. INTERVENTIONS: At 15min before the induction of anesthesia, 152 patients received intravenously parecoxib sodium 40mg and dexmedetomidine at a dose of 0...
September 2017: Journal of Clinical Anesthesia
https://www.readbyqxmd.com/read/28748840/cardiovascular-involvement-in-severe-malaria-a-prospective-study-in-ranchi-jharkhand
#14
Hemant Narayan Ray, Darshit Doshi, Appu Rajan, Amit K Singh, S B Singh, M K Das
BACKGROUND & OBJECTIVES: Malaria is considered as the most important parasitic disease of humans, causing seri- ous illness that can be fatal, if not diagnosed and treated immediately. It is a multisystem disorder affecting nearly every system of the body. The aim of the present study was to evaluate the involvement of cardiovascular system in severe malaria using non-invasive methods. METHODS: This prospective study was conducted on patients of severe malaria who were admitted between June and November 2015 in the Department of Medicine, Rajendra Institute of Medical Sciences and Hospital, Ranchi, Jharkhand, India...
April 2017: Journal of Vector Borne Diseases
https://www.readbyqxmd.com/read/28713431/an-unexpected-cause-of-bradycardia-in-a-patient-with-bacterial-meningitis
#15
Petros Ioannou, Magdalini Velegraki, Stella Soundoulounaki, Achilleas Gikas, Diamantis P Kofteridis
Sinus bradycardia which is a sinus rhythm with a resting heart rate of less than 60 bpm is caused by intrinsic cardiac disorders like sick sinus syndrome or inferior myocardial infarction, metabolic and environmental causes (such as hypothyroidism and electrolyte disorders), medications (such as beta-blockers and amiodarone), infection (such as myocarditis), increased intracranial pressure, and toxic exposure, while it can sometimes be a normal phenomenon, especially during sleep, in athletes, and during pregnancy...
2017: Case Reports in Medicine
https://www.readbyqxmd.com/read/28690945/pacemaker-placement-in-persistent-left-superior-vena-cava
#16
Murtaza Sundhu, Mubbasher Syed, Sajjad Gul, Bilal Saqi, Robert Mosteller
Persistent left superior vena cava (PLSVC) is a rare disorder which is asymptomatic and hence is usually discovered while performing interventions through the left subclavian vein. We present a case of a 78-year-old male who was undergoing elective placement of a permanent pacemaker for tachycardia - bradycardia syndrome with post-conversion pauses of up to nine seconds. After achieving access through the left subclavian vein the wire kept on going on the left side of the chest instead of crossing the midline to the right side...
June 5, 2017: Curēus
https://www.readbyqxmd.com/read/28684593/point-exercise-training-induced-bradycardia-is-caused-by-changes-in-intrinsic-sinus-node-function
#17
Mark R Boyett, Yanwen Wang, Shu Nakao, Jonathan Ariyaratnam, George Hart, Oliver Monfredi, Alicia D'Souza
N/A.
July 6, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28674041/transient-notch-activation-induces-long-term-gene-expression-changes-leading-to-sick-sinus-syndrome-in-mice
#18
Yun Qiao, Catherine Lipovsky, Stephanie Hicks, Somya Bhatnagar, Gang Li, Aditi Khandekar, Robert Guzy, Kel Vin Woo, Colin G Nichols, Igor R Efimov, Stacey Rentschler
RATIONALE: Notch signaling programs cardiac conduction during development, and in the adult ventricle, injury-induced Notch reactivation initiates global transcriptional and epigenetic changes. OBJECTIVE: To determine whether Notch reactivation may stably alter atrial ion channel gene expression and arrhythmia inducibility. METHODS AND RESULTS: To model an injury response and determine the effects of Notch signaling on atrial electrophysiology, we transiently activate Notch signaling within adult myocardium using a doxycycline-inducible genetic system (inducible Notch intracellular domain [iNICD])...
August 18, 2017: Circulation Research
https://www.readbyqxmd.com/read/28668627/vigabatrin-lacks-proarrhythmic-potential-results-from-a-thorough-qt-qtc-study-in-healthy-volunteers
#19
Dwain Tolbert, Susan Reid, Stuart Harris, Ihor Bekersky
PURPOSE: A thorough QT study was performed to assess the proarrhythmic potential of vigabatrin, an antiepileptic drug approved in the United States for the treatment of infantile spasms and refractory complex partial seizures. METHODS: In this Phase I, randomized, double-blind, placebo- and active-controlled (moxifloxacin), 4-sequence, crossover study conducted at a single center, healthy participants received 1 of 4 randomly assigned treatments: 3.0g vigabatrin solution (therapeutic dose) and 1 moxifloxacin placebo tablet; 6...
June 28, 2017: Clinical Therapeutics
https://www.readbyqxmd.com/read/28666317/right-ventricular-and-tricuspid-valve-function-in-patients-chronically-implanted-with-leadless-pacemakers
#20
Erwan Salaun, Lilith Tovmassian, Blandine Simonnet, Roch Giorgi, Frédéric Franceschi, Linda Koutbi-Franceschi, Jérôme Hourdain, Gilbert Habib, Jean-Claude Deharo
Aims: Leadless cardiac pacing has recently been proposed as alternative to conventional right ventricular (RV) pacing. With this approach, devices are directly screwed or fixed with tines in the RV wall, but the possible consequences on RV and tricuspid valve (TV) structure and function remain unknown. We thus conducted a study to evaluate this potential impact in chronically implanted patients. Methods and results: Repeated echocardiographic studies were performed prior to implantation, at discharge, and 2 months thereafter on all consecutive patients implanted with a leadless pacemaker at our centre between October 2014 and end-December 2015...
June 28, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
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