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Atrial electrical remodeling

Anna M May, David R Van Wagoner, Reena Mehra
A surge of data has reproducibly identified strong associations of obstructive sleep apnea (OSA) with cardiac arrhythmias. As an extension of epidemiologic and clinic-based findings, experimental investigations have made strides in advancing our understanding of the putative OSA and cardiac arrhythmogenesis mechanistic underpinnings. While most studies have focused on the links between OSA and atrial fibrillation (AF), relationships with ventricular arrhythmias have also been characterized. Key findings implicate OSA-related autonomic nervous system fluctuations typified by enhanced parasympathetic activation during and sympathetic surges subsequent to respiratory events which contribute to augmented arrhythmic propensity...
September 29, 2016: Chest
Zewei Sun, Dongchen Zhou, Xudong Xie, Shuai Wang, Zhen Wang, Wenting Zhao, Hongfei Xu, Liangrong Zheng
Increased macrophage accumulation occurs in the atria of patients with atrial fibrillation (AF). However, the phenotype and functions of the macrophages in AF remain unclear. We investigated the macrophage-atrial myocyte interaction in AF patients and found that the increased macrophages were mainly pro-inflammatory macrophages (iNOS(+), Arg1(-)). Tachypacing of HL-1 atrial myocytes also led to pro-inflammatory macrophage polarization. In addition, lipopolysaccharide (LPS)-stimulated pro-inflammatory macrophages-induced atrial electrical remodeling, evidenced by increased AF incidence and decreased atrial effective refractory period and L-type calcium currents (I Ca-L) in both canine and mouse AF models...
November 2016: Basic Research in Cardiology
Yuichi Hori, Shiro Nakahara, Naofumi Anjo, Ayako Nakagawa, Naoki Nishiyama, Kouta Yamada, Akiko Hayashi, Takaaki Komatsu, Sayuki Kobayashi, Yoshihiko Sakai, Isao Taguchi
PURPOSE: The atrial conduction time measured by echocardiography using tissue Doppler imaging (TDI) has been reported as a predictive factor of left atrial (LA) remodeling. We investigated the P wave to LA appendage (LAA) conduction time defined by transthoracic echocardiography using TDI (P-LAA TDI), and directly compared the actual LA electrical conduction time determined by the electrophysiological data. Additionally, we confirmed the clinical utility of the P-LAA TDI by examining the relationship to the electroanatomical LA remodeling data...
September 22, 2016: Journal of Interventional Cardiac Electrophysiology: An International Journal of Arrhythmias and Pacing
Wei Wang, Yun Zhu, Jianguang Yi, Wei Cheng
Remodeling of atrial electrophysiology and structure is the primary feature of atrial fibrillation (AF). Evidence suggests that abnormalities in the expression levels of embryological cardiovascular development‑associated transcription factors, including Nkx2.5, are crucial for the development of AF. Rat atrial myocardial cells (AMCs) in culture dishes were placed in an electric field and stimulated. Transmission electron microscopy was used to observe the ultrastucture prior to and following rapid pacing...
October 2016: Molecular Medicine Reports
J H Coote, R A Chauhan
Autonomic control of the heart has a significant influence over development of life threatening arrhythmias that can lead to sudden cardiac death. Sympathetic activity is known to be upregulated during these conditions and hence the sympathetic nerves present a target for treatment. However, a better understanding of the anatomy and physiology of cardiac sympathetic nerves is required for the progression of clinical interventions. This review explores the organization of the cardiac sympathetic nerves, from the preganglionic origin to the postganglionic innervations, and provides an overview of literature surrounding anti-arrhythmic therapies including thoracic sympathectomy and dorsal spinal cord stimulation...
August 2016: Autonomic Neuroscience: Basic & Clinical
Yung-Hsin Yeh, Lung-An Hsu, Ying-Hwa Chen, Chi-Tai Kuo, Gwo-Jyh Chang, Wei-Jan Chen
Structural and electrical remodeling in the atrium constitutes the main feature of atrial fibrillation (AF), which is characterized by increased oxidative stress. Heme oxygenase-1 (HO-1) is a potent anti-oxidant system that may provide protection against various oxidative stress-related diseases. The aim of this study is to investigate whether HO-1 has a protective effect on AF-related remodeling. Cultured atrium-derived myocytes (HL-1 cell line) were used to evaluate tachypacing-induced oxidative stress, structural, and electrical remodeling...
September 2016: Basic Research in Cardiology
Adéla Matějková, Ivo Šteiner
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. For long time it was considered as pure functional disorder, but in recent years, there were identified atrial locations, which are involved in the initiation and maintenance of this arrhythmia. These structural changes, so called remodelation, start at electric level and later they affect contractility and morphology. In this study we attempted to find a possible relation between morphological (scarring, amyloidosis, left atrial (LA) enlargement) and electrophysiological (ECG features) changes in patients with AF...
2016: Acta Medica (Hradec Králové)
Yoshio Takemoto, Rafael J Ramirez, Miki Yokokawa, Kuljeet Kaur, Daniela Ponce-Balbuena, Mohamad C Sinno, B Cicero Willis, Hamid Ghanbari, Steven R Ennis, Guadalupe Guerrero-Serna, Bettina C Henzi, Rakesh Latchamsetty, Roberto Ramos-Mondragon, Hassan Musa, Raphael P Martins, Sandeep V Pandit, Sami F Noujaim, Thomas Crawford, Krit Jongnarangsin, Frank Pelosi, Frank Bogun, Aman Chugh, Omer Berenfeld, Fred Morady, Hakan Oral, José Jalife
OBJECTIVES: To determine whether Gal-3 mediates sustained atrial fibrillation (AF)-induced atrial structural and electrical remodeling and contributes to AF perpetuation. BACKGROUND: Galectin-3 (Gal-3) mediates extracellular matrix remodeling in heart failure, but its role in AF progression remains unexplored. METHODS: We examined intracardiac blood samples from patients with AF (N=55) to identify potential biomarkers of AF recurrence. In a sheep model of tachypacing-induced AF (N=20), we tested the effects of Gal-3 inhibition during AF progression...
April 2016: JACC. Basic to Translational Science
Mingyan Dai, Mingwei Bao, Yijie Zhang, Lilei Yu, Quan Cao, Yanhong Tang, He Huang, Xi Wang, Dan Hu, Congxin Huang
BACKGROUND: Low-level carotid baroreflex stimulation (LL-CBS) appears to have potential antiarrhythmogenic effect. OBJECTIVES: To investigate effects of short term LL-CBS on atrial fibrillation (AF) canine model. METHODS: Group 1: anesthetized dogs underwent 6 h of rapid atrial pacing (RAP) with concomitant LL-CBS in last three hours (LL-CBS group, n=7) or without (Control group, n=6). Effective refractory period (ERP), ERP dispersion, and window of vulnerability (WOV) to AF were determined...
August 9, 2016: Heart Rhythm: the Official Journal of the Heart Rhythm Society
Fengping He, Xin Xu, Shuguo Yuan, Liangqiu Tan, Lingjun Gao, Shaochun Ma, Shebin Zhang, Zhanzhong Ma, Wei Jiang, Fenglian Liu, Baofeng Chen, Beibei Zhang, Jungang Pang, Xiuyan Huang, Jiaqiang Weng
Atrial fibrillation (AF) is the most common sustained arrhythmia causing high morbidity and mortality. While changing of the cellular calcium homeostasis plays a critical role in AF, the L-type calcium channel α1c protein has suggested as an important regulator of reentrant spiral dynamics and is a major component of AF-related electrical remodeling. Our computational modeling predicted that miRNA-223 may regulate the CACNA1C gene which encodes the cardiac L-type calcium channel α1c subunit. We found that oxidized low-density lipoprotein (ox-LDL) cholesterol significantly up-regulates both the expression of miRNA-223 and L-type calcium channel protein...
2016: Scientific Reports
Suvash Shrestha, On Chen, Mary Greene, Jinu Jacob John, Yisachar Greenberg, Felix Yang
Convergent atrial fibrillation ablation involves extensive epicardial as well as endocardial ablation of the left atrium. We examined whether it changes the morphology of the surface P wave. We reviewed electrocardiograms of 29 patients who underwent convergent ablation for atrial fibrillation. In leads V1, II and III, we measured P wave duration, area and amplitude before ablation, and at 1, 3 and 6 months from ablation. After ablation, there were no significant changes in P wave amplitude, area, or duration in leads II and III...
January 2016: Indian Pacing and Electrophysiology Journal
X Zhang, Y Zhang, F Gao, F Zhang, Z Yang, S Ouyang, M Rao, Y Hou
Atrial fibrillation (AF) is the most prevalent heart rhythm disorder, and autonomic nervous system (ANS) is important to AF. This study aims to identify whether changes in transmitters released by ANS could reflect their activities. The right atrium (RA) groups (1-40V) included RA500 and RA1000. While ANS groups received high-frequency electrical stimulation (1-8V, 20 Hz, 2 ms), including left stellate ganglion stimulation (LSGS) andleft cervical vagus trunk stimulation (LVTS). The induced rate of AF, duration and atrial effective refractory period (AERP) were measured...
2016: Cellular and Molecular Biology
Irina A Polejaeva, Ravi Ranjan, Christopher J Davies, Misha Regouski, Justin Hall, Aaron L Olsen, Qinggang Meng, Heloisa M Rutigliano, Derek J Dosdall, Nathan A Angel, Frank B Sachse, Thomas Seidel, Aaron J Thomas, Rusty Stott, Kip E Panter, Pamela M Lee, Arnaud J VAN Wettere, John R Stevens, Zhongde Wang, Rob S Macleod, Nassir F Marrouche, Kenneth L White
INTRODUCTION: Large animal models of progressive atrial fibrosis would provide an attractive platform to study relationship between structural and electrical remodeling in atrial fibrillation (AF). Here we established a new transgenic goat model of AF with cardiac specific overexpression of TGF-β1 and investigated the changes in the cardiac structure and function leading to AF. METHODS AND RESULTS: Transgenic goats with cardiac specific overexpression of constitutively active TGF-β1 were generated by somatic cell nuclear transfer...
October 2016: Journal of Cardiovascular Electrophysiology
Agnieszka A Książek, Katharyn J Mitchell, Laurent Morax, Colin C Schwarzwald, Simon P Hoerstrup, Benedikt Weber
BACKGROUND: Heterotopic heart transplantation (HHT) in rodent animal models represents an important technique enabling studies on organ transplantation immunology and pharmaceutical development. Recent investigations used nonworking HHT designs, with the left ventricle (LV) bypassed in the anastomosis system. In spite of their principal success, the lack of orthogonal ventricular filling leads to myocardial atrophy. However, when focusing on the cellular and molecular mechanisms involved in the in vivo remodeling of the myocardium or cell-based cardiovascular implants, a nonworking model is suboptimal as it lacks the native-analogous hemodynamic and metabolic situation...
July 20, 2016: European Surgical Research. Europäische Chirurgische Forschung. Recherches Chirurgicales Européennes
Kamil Tuluce, Cemal Kara, Selcen Yakar Tuluce, Nurullah Cetin, Caner Topaloglu, Yasemin Turhan Bozkaya, Ali Saklamaz, Cahide Soydas Cinar, Oktay Ergene
BACKGROUND: This study evaluated the early postoperative benefits of laparoscopic sleeve gastrectomy (LSG) on the left ventricular (LV) function and left atrial (LA) structural, mechanical, and electrical functions in severely obese patients. METHODS: Thirty-two patients with severe obesity who were consecutively scheduled for LSG and 30 healthy controls were included in the study. LV global longitudinal strain (LGS), peak atrial longitudinal strain (PALS), and strain rates (S-Sr, E-Sr, and A-Sr) of the lateral and septal LA walls, and intra- and interatrial dyssynchrony periods for all subjects were evaluated using strain echocardiography...
July 19, 2016: Obesity Surgery
Esteban Orenes-Piñero, Mariano Valdés, Gregory Y H Lip, Francisco Marín
Atrial fibrillation (AF) is the most common arrhythmia in clinical practice and is associated with decreased quality of life, and increased mortality and morbidity from stroke and thromboembolism. The underlying mechanisms involved in the development of AF have yet to be fully elucidated. However, once initiated, AF tends to self-perpetuate, due to structural and electrical remodeling in the atria. Currently, therapies for AF, such as, antiarrhythmic drugs and catheter ablation, have significant limitations...
August 2015: Drug Metabolism Reviews
Akira Satoh, Shinichi Niwano, Hiroe Niwano, Jun Kishihara, Yuya Aoyama, Jun Oikawa, Hidehira Fukaya, Hideaki Tamaki, Junya Ako
Aliskiren, a direct renin inhibitor is expected to achieve sufficient suppression of renin-angiotensin system. We evaluated the effect of aliskiren on the electrical and structural remodeling in a canine atrial fibrillation (AF) model. Twenty-eight dogs were divided into three groups: (1) pacing control group (n = 12), with continuous atrial rapid pacing for 3 or 6 weeks, (2) pacing + aliskiren group (n = 12), with oral aliskiren (30 mg/kg/day), and (3) sham group (n = 4), no pacing nor drug administration...
July 11, 2016: Heart and Vessels
Junaid A B Zaman, Leanne Harling, Hutan Ashrafian, Ara Darzi, Nigel Gooderham, Thanos Athanasiou, Nicholas S Peters
BACKGROUND: Post-operative atrial fibrillation (POAF) is a major health economic burden. However, the precise mechanisms in POAF remain unclear. In other forms of AF, sites of high dominant frequency (DF) in sinus rhythm (SR) may harbour 'AF nests'. We studied AF inducibility in relation to substrate changes using epicardial electrograms and cardiomyocyte calcium handling in the atria of AF naïve patients. METHOD: Bipolar electrograms were recorded from the lateral right atrial (RA) wall in 34 patients undergoing coronary surgery using a high-density array in sinus rhythm (NSR)...
October 1, 2016: International Journal of Cardiology
Mitsuru Seki, Ryan LaCanna, Jeffery C Powers, Christine Vrakas, Fang Liu, Remus Berretta, Geena Chacko, John Holten, Pooja Jadiya, Tao Wang, Jeffery S Arkles, Joshua M Copper, Steven R Houser, Jianhe Huang, Vickas V Patel, Fabio A Recchia
Current therapies are less effective for treating sustained/permanent versus paroxysmal atrial fibrillation (AF). We and others have previously shown that histone deacetylase (HDAC) inhibition reverses structural and electrical atrial remodeling in mice with inducible, paroxysmal-like AF. Here, we hypothesize an important, specific role for class I HDACs in determining structural atrial alterations during sustained AF. The class I HDAC inhibitor N-acetyldinaline [4-(acetylamino)-N-(2-amino-phenyl) benzamide] (CI-994) was administered for 2 weeks (1 mg/kg/day) to Hopx transgenic mice with atrial remodeling and inducible AF and to dogs with atrial tachypacing-induced sustained AF...
September 2016: Journal of Pharmacology and Experimental Therapeutics
Yujie Zhao, Yiqiang Yuan, Chunguang Qiu
BACKGROUND The objective of this study was to investigate the molecular mechanism of atrial fibrillation (AF), as well as the negative regulatory relationship between miR-29a-3p and CACNA1C. MATERIAL AND METHODS We searched the online miRNA database ( and identified the miR-29a-3p binding sequence within the 3'-UTR of the target gene, and then conducted luciferase assay to verify it. The cells were transfected with miR-29a-3p and ICa,L was determined in those cells. RESULTS We validated CACNA1C to be the direct target gene of miR-29a-3p...
2016: Medical Science Monitor: International Medical Journal of Experimental and Clinical Research
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