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Atrial- Ventricular block

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https://www.readbyqxmd.com/read/28892643/comparison-of-the-effects-of-i-sub-k-ach-sub-i-sub-kr-sub-and-i-sub-na-sub-block-in-conscious-dogs-with-atrial-fibrillation-and-on-action-potentials-in-remodeled-atrial-trabeculae
#1
Viktor Juhász, Tibor Hornyik, Attila Benák, Norbert Nagy, Zoltan Husti, Robert Pap, László Sághy, László Virág, András Varró, István Baczkó
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and a major cause of morbidity and mortality. Traditional antiarrhythmic agents used for restoration of sinus rhythm have limited efficacy in long-term AF and they may possess ventricular proarrhythmic adverse effects, especially in patients with structural heart disease. The acetylcholin receptor-activated potassium channel (I<sub>K,ACh</sub>) represents an atrial-selective target for future AF management. We investigated the effects of the I<sub>K,ACh</sub> blocker tertiapin-Q (TQ), a derivative of the honeybee toxin tertiapin, on chronic atrial tachypacing induced AF in conscious dogs, without the influence of anesthetics that modulate a number of cardiac ion channels...
September 11, 2017: Canadian Journal of Physiology and Pharmacology
https://www.readbyqxmd.com/read/28877886/pulmonary-right-ventricular-resynchronization-in-congenital-heart-disease-acute-improvement-in-right-ventricular-mechanics-and-contraction-efficiency
#2
Jan Janoušek, Jan Kovanda, Miroslav Ložek, Viktor Tomek, Pavel Vojtovič, Roman Gebauer, Peter Kubuš, Miroslav Krejčíř, Joost Lumens, Tammo Delhaas, Frits Prinzen
BACKGROUND: Electromechanical discoordination may contribute to long-term pulmonary right ventricular (RV) dysfunction in patients after surgery for congenital heart disease. We sought to evaluate changes in RV function after temporary RV cardiac resynchronization therapy. METHODS AND RESULTS: Twenty-five patients aged median 12.0 years after repair of tetralogy of Fallot and similar lesions were studied echocardiographically (n=23) and by cardiac catheterization (n=5) after primary repair (n=4) or after surgical RV revalvulation for significant pulmonary regurgitation (n=21)...
September 2017: Circulation. Cardiovascular Imaging
https://www.readbyqxmd.com/read/28871329/transforming-growth-factor-%C3%AE-mediated-cd44-stat3-signaling-contributes-to-the-development-of-atrial-fibrosis-and-fibrillation
#3
Shang-Hung Chang, Yung-Hsin Yeh, Jia-Lin Lee, Yu-Juei Hsu, Chi-Tai Kuo, Wei-Jan Chen
Atrial fibrillation (AF) is associated with atrial fibrosis. Inhibition of atrial fibrosis might be a plausible approach for AF prevention and therapy. This study is designed to evaluate the potential role of CD44, a membrane receptor known to regulate fibrosis, and its related signaling in the pathogenesis of atrial fibrosis and AF. Treatment of cultured rat atrial fibroblasts with transforming growth factor-β (TGF-β, a key mediator of atrial fibrosis) led to a higher expression of hyaluronan (HA), CD44, STAT3, and collagen (a principal marker of fibrosis) than that of ventricular fibroblasts...
September 4, 2017: Basic Research in Cardiology
https://www.readbyqxmd.com/read/28857929/episodes-of-second-degree-ventriculo-atrial-block-during-ventricular-tachycardia
#4
Carmelo Buttà, Antonino Tuttolomondo, Domenico Di Raimondo, Lucia Giarrusso, Giuseppe Miceli, Giuseppe Brunori, Antonio Pinto
No abstract text is available yet for this article.
October 2017: Journal of Cardiovascular Medicine
https://www.readbyqxmd.com/read/28855177/small-functional-if-current-in-sinoatrial-pacemaker-cells-of-the-brown-trout-salmo-trutta-fario-heart-despite-strong-expression-of-hcn-channel-transcripts
#5
Minna Hassinen, Jaakko Haverinen, Matti Vornanen
Funny current (If), formed by hyperpolarization-activated HCN channels, is supposed to be crucial for membrane clock regulating the cardiac pacemaker mechanism. We examined the presence and activity of HCN channels in the brown trout (Salmo trutta fario) sinoatrial (SA) pacemaker cells, and their putative role in heart rate (fH) regulation. Six HCN transcripts (HCN1, HCN2a, HCN2ba, HCN2bb, HCN3 and HCN4) were expressed in the brown trout heart. The total HCN transcript abundance was 4.0 and 4.9 times higher in SA pacemaker tissue than in atrium and ventricle, respectively...
August 30, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/28846146/paroxysmal-atrioventricular-block-electrophysiological-mechanism-of-phase-4-conduction-block-in-the-his-purkinje-system-a-comparison-with-phase-3-block
#6
Mohammad Shenasa, Mark E Josephson, Andrew L Wit
BACKGROUND: Paroxysmal atrioventricular (A-V) block is relatively rare, and due to its transient nature, it is often under recognized. It is often triggered by atrial, junctional or ventricular premature beats, and occurs in the presence of a diseased His-Purkinje system (HPS). Here we present a 45-year-old white male who was admitted for observation due to recurrent syncope and near-syncope, who had paroxysmal A-V block. The likely cellular electrophysiological mechanisms(s) of paroxysmal A-V block and its differential diagnosis and management are discussed...
August 28, 2017: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/28821328/atrioventricular-block-masked-by-posteroseptal-bypass-tract-located-in-coronary-sinus-aneurysm
#7
Michael C Y Nam, Matthew Wilkins, Alana Harris, Naresh Dayananda
Atrial fibrillation with concurrent ventricular preexcitation identifies a high-risk arrhythmic substrate and usually results in catheter ablation of the atrioventricular bypass tract. Electrocardiography can only approximate the anatomical location of an accessory pathway. Here we report a case where a bypass tract was localised to a coronary sinus aneurysm and antegrade atrioventricular conduction masked underlying atrioventricular nodal block.
July 12, 2017: Journal of Electrocardiology
https://www.readbyqxmd.com/read/28774377/association-of-estimated-sodium%C3%A2-intake%C3%A2-with-adverse-cardiac-structure-and%C3%A2-function-from-the-hypergen-study
#8
MULTICENTER STUDY
Senthil Selvaraj, Luc Djoussé, Frank G Aguilar, Eva E Martinez, Vincenzo B Polsinelli, Marguerite R Irvin, Donna K Arnett, Sanjiv J Shah
BACKGROUND: The optimal level of sodium intake remains controversial. OBJECTIVES: This study sought to determine whether examination of left ventricular longitudinal strain (LS), circumferential strain, and e' velocity can provide insight into thresholds for the detrimental effects of estimated sodium intake (ESI) on subclinical cardiovascular disease. METHODS: We performed speckle-tracking analysis on HyperGEN (Hypertension Genetic Epidemiology Network) study echocardiograms with available urinary sodium data (N = 2,996)...
August 8, 2017: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/28765763/elongated-ascending-aorta-predicts-a-short-distance-between-his-bundle-potential-recording-site-and-coronary-sinus-ostium
#9
Yuichi Momose, Kyoko Soejima, Akiko Ueda, Takahiro Arai, Masamichi Koyanagi, Yo Hagiwara, Ikuko Togashi, Yosuke Miwa, Kyoko Hoshida, Mutsumi Miyakoshi, Noriko Matsushita, Mika Nagaoka, Toshiaki Sato, Toshiaki Nitatori, Hideaki Yoshino
BACKGROUND: When performing catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT), it can be difficult to maintain a safe distance from the His recording site to avoid AV block in patients with a short distance between this recording site to the coronary sinus (CS) ostium (small triangle of Koch [TOK]). In this study, we sought to identify parameters predicting small TOK and test these parameters in patients undergoing AVNRT catheter ablation. METHODS: Twenty-eight patients who underwent catheter ablation of atrial fibrillation using a three-dimensional (3D) electroanatomical mapping system (EAM) with computed tomography (CT) merge (23 males; mean age, 65...
August 2017: Journal of Arrhythmia
https://www.readbyqxmd.com/read/28765761/simulation-of-ventricular-rate-control-during-atrial-fibrillation-using-ionic-channel-blockers
#10
Shin Inada, Nitaro Shibata Md PhD, Michiaki Iwata PhD, Ryo Haraguchi PhD, Takashi Ashihara Md PhD, Takanori Ikeda Md PhD, Kazuyuki Mitsui PhD, Halina Dobrzynski PhD, Mark R Boyett PhD, Kazuo Nakazawa PhD
BACKGROUND: The atrioventricular (AV) node is the only compartment that conducts an electrical impulse between the atria and the ventricles. The main role of the AV node is to facilitate efficient pumping by conducting excitation slowly between the two chambers as well as reduce the ventricular rate during atrial fibrillation (AF). METHODS: Using computer simulations, we investigated excitation conduction from the right atrium to the bundle of His during high-rate atrial excitation with or without partial blocking of the calcium or potassium ionic current...
August 2017: Journal of Arrhythmia
https://www.readbyqxmd.com/read/28765737/local-atrial-ventricular-ratio-as-an-adjuvant-marker-for-catheter-ablation-of-atrioventricular-accessory-pathways
#11
Ki-Hun Kim, Dae-Kyeong Kim, Hyun-Ji Im, Jeong-Sook Seo, Han-Young Jin, Jae-Sik Jang, Tae-Hyun Yang, Dong-Soo Kim, So-Young Jeong, Yun Seok Song, Dong-Kie Kim, Pil-Sang Song, Sang-Hoon Seol, Doo-Il Kim
BACKGROUND AND OBJECTIVES: The earliest atrial (A)/ventricular (V) activation potential, or accessory pathway (AP) potential are commonly used as ablation targets for atrioventricular (AV) APs. However, these targets are sometimes ambiguous. SUBJECTS AND METHODS: We reviewed 119 catheter ablation cases in 112 patients diagnosed with orthodromic atrioventricular reentrant tachycardia (AVRT) or Wolff-Parkinson-White (WPW) syndrome. Local A/V amplitude potentials with the earliest activation or AP potential were measured shortly before achieving antegrade AP conduction block, ventriculoatrial block during right ventricle (RV) pacing, or AVRT termination with no AP conduction...
July 2017: Korean Circulation Journal
https://www.readbyqxmd.com/read/28765088/the-evolving-role-of-ankyrin-b-in-cardiovascular-disease
#12
Sara N Koenig, Peter J Mohler
Over the past decade, ankyrin-B has been identified as a prominent player in cardiac physiology. Ankyrin-B has a multitude of functions, with roles in expression, localization, and regulation of proteins critical for cardiac excitability, cytoskeletal integrity, and signaling. Furthermore, human ANK2 variants that result in ankyrin-B loss of function are associated with "ankyrin-B syndrome," a complex cardiac phenotype that may include bradycardia and heart rate variability, conduction block, atrial fibrillation, QT interval prolongation, and potentially fatal catecholaminergic polymorphic ventricular tachycardia...
July 29, 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/28760211/implantable-cardiac-monitors-in-high-risk-post-infarction-patients-with-cardiac-autonomic-dysfunction-and-moderately-reduced-left-ventricular-ejection-fraction-design-and-rationale-of-the-smart-mi-trial
#13
RANDOMIZED CONTROLLED TRIAL
Wolfgang Hamm, Konstantinos D Rizas, Lukas von Stülpnagel, Nikolay Vdovin, Steffen Massberg, Stefan Kääb, Axel Bauer
BACKGROUND: Most deaths after myocardial infarction (MI) occur in patients with left ventricular ejection fraction (LVEF) >35%, for whom no specific prophylactic strategies exist. Deceleration capacity (DC) of heart rate and periodic repolarization dynamics (PRD) are noninvasive electrophysiological markers depending on the vagal and sympathetic tone. The combination of abnormal DC and/or PRD identifies a new high-risk group among postinfarction patients with LVEF 36%-50%. This new high-risk group has similar characteristics with respect to prognosis and patient numbers to those of the established high-risk group identified by LVEF ≤ 35%...
August 2017: American Heart Journal
https://www.readbyqxmd.com/read/28760133/surface-ecg-interatrial-block-guided-treatment-for-stroke-prevention-rationale-for-an-attractive-hypothesis
#14
Antoni Bayés de Luna, Manuel Martínez-Sellés, Antoni Bayés-Genís, Roberto Elosua, Adrian Baranchuk
Atrial fibrillation (AF) is the most common sustained arrhythmia and is associated with stroke, cognitive impairment, and cardiovascular death. Some predisposing factors - as aging, diabetes, hypertension - induce and maintain electrophysiological and ultrastructural remodeling that usually includes fibrosis. Interatrial conduction disturbances play a crucial role in the initiation of atrial fibrosis and in its associated complications. The diagnosis of interatrial blocks (IABs) is easy to perform using the surface ECG...
July 31, 2017: BMC Cardiovascular Disorders
https://www.readbyqxmd.com/read/28736019/endomyocardial-biopsy-via-the-femoral-vein-using-a-long-curved-sheath
#15
N Naderi, S Taghavi, A Amin, G Houshmand, K Mozaffari, M Maleki
BACKGROUND: Endomyocardial biopsy (EMB) has been defined as the gold standard method for surveillance of rejection after heart transplantation, and it has also been used in the diagnosis of myocarditis and the unknown causes of cardiomyopathies. The procedure, however, is not free from complications. Access through the jugular vein or the femoral vein is the standard approach. In this study, we performed biopsies by using a long, curved sheath and evaluated the rate of complications with this technique...
July 2017: Transplantation Proceedings
https://www.readbyqxmd.com/read/28728742/a-clinical-score-model-to-predict-lethal-events-in-young-patients-%C3%A2-19-years-with-the-brugada-syndrome
#16
M Cecilia Gonzalez Corcia, Juan Sieira, Gudrun Pappaert, Carlo de Asmundis, Gian Battista Chierchia, Andrea Sarkozy, Pedro Brugada
Risk stratification in Brugada syndrome in young patients remains challenging. We investigated the clinical characteristics, prognosis, and risk in young patients with the Brugada syndrome. We studied 95 patients with the Brugada syndrome aged ≤19 years. The median age at diagnosis was 12.9 years. The clinical presentation was sudden cardiac death in 7% and syncope in 21%. The remaining 72% were asymptomatic at diagnosis. Electrical abnormalities were present in 36%, including spontaneous type I electrocardiogram (12%), sinus node dysfunction (9%), atrioventricular block (17%), intraventricular conduction delay (16%), and atrial arrhythmias (8%)...
September 1, 2017: American Journal of Cardiology
https://www.readbyqxmd.com/read/28728260/-clinical-analysis-of-pacing-therapy-and-treatment-of-complications-during-follow-up-in-children
#17
P J Zhao, Y W Chen, F Li, Y Li, J P Yang, J J Wu
Objective: To analyze characteristics of permanent pacemaker implantation in children as well as treatment and prognosis of complications. Method: Clinical data of children who underwent endocardial or epicardial permanent pacemaker implantation between April 2000 and June 2016 in Shanghai Xinhua Hospital and Shanghai Children's Medical Center were analyzed retrospectively. These patients were discharged 5 days after implantation. Electrocardiogram, chest X ray, echocardiography and pacemaker programming were performed during follow-up...
July 2, 2017: Zhonghua Er Ke za Zhi. Chinese Journal of Pediatrics
https://www.readbyqxmd.com/read/28708290/rationale-and-design-of-the-adaptresponse-trial-a-prospective-randomized-study-of-cardiac-resynchronization-therapy-with-preferential-adaptive-left-ventricular-only-pacing
#18
Gerasimos Filippatos, David Birnie, Michael R Gold, Bart Gerritse, Ahmad Hersi, Sandra Jacobs, Kengo Kusano, Christophe Leclercq, Wilfried Mullens, Bruce L Wilkoff
The AdaptResponse trial is designed to test the hypothesis that preferential adaptive left ventricular-only pacing with the AdaptivCRT(®) algorithm reduces the incidence of the combined endpoint of all-cause mortality and intervention for heart failure (HF) decompensation, compared with conventional cardiac resynchronization therapy (CRT), among patients with a CRT indication, left bundle branch block (LBBB) and normal atrioventricular (AV) conduction. The AdaptResponse study is a prospective, randomized, controlled, single-blinded, multicentre, clinical trial (ClinicalTrials...
July 2017: European Journal of Heart Failure
https://www.readbyqxmd.com/read/28706272/modeling-atrial-fibrillation-using-human-embryonic-stem-cell-derived-atrial-tissue
#19
Zachary Laksman, Marianne Wauchop, Eric Lin, Stephanie Protze, Jeehoon Lee, Wallace Yang, Farzad Izaddoustdar, Sanam Shafaattalab, Lior Gepstein, Glen F Tibbits, Gordon Keller, Peter H Backx
Since current experimental models of Atrial Fibrillation (AF) have significant limitations, we used human embryonic stem cells (hESCs) to generate an atrial-specific tissue model of AF for pharmacologic testing. We generated atrial-like cardiomyocytes (CMs) from hESCs which preferentially expressed atrial-specific genes, and had shorter action potential (AP) durations compared to ventricular-like CMs. We then generated confluent atrial-like CM sheets and interrogated them using optical mapping techniques. Atrial-like CM sheets (~1 cm in diameter) showed uniform AP propagation, and rapid re-entrant rotor patterns, as seen in AF could be induced...
July 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28705318/progressive-atrial-conduction-defects-associated-with-bone-malformation-caused-by-a-connexin-45-mutation
#20
Akiko Seki, Taisuke Ishikawa, Xavier Daumy, Hiroyuki Mishima, Julien Barc, Ryo Sasaki, Kiyomasa Nishii, Kayoko Saito, Mari Urano, Seiko Ohno, Saki Otsuki, Hiroki Kimoto, Alban-Elouen Baruteau, Aurelie Thollet, Swanny Fouchard, Stéphanie Bonnaud, Philippe Parent, Yosaburo Shibata, Jean-Philippe Perrin, Hervé Le Marec, Nobuhisa Hagiwara, Sandra Mercier, Minoru Horie, Vincent Probst, Koh-Ichiro Yoshiura, Richard Redon, Jean-Jacques Schott, Naomasa Makita
BACKGROUND: Inherited cardiac conduction disease is a rare bradyarrhythmia associated with mutations in various genes that affect action potential propagation. It is often characterized by isolated conduction disturbance of the His-Purkinje system, but it is rarely described as a syndromic form. OBJECTIVES: The authors sought to identify the genetic defect in families with a novel bradyarrhythmia syndrome associated with bone malformation. METHODS: The authors genetically screened 15 European cases with genotype-negative de novo atrioventricular (AV) block and their parents by trio whole-exome sequencing, plus 31 Japanese cases with genotype-negative familial AV block or sick sinus syndrome by targeted exon sequencing of 457 susceptibility genes...
July 18, 2017: Journal of the American College of Cardiology
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