Atrial fibrillation and right atria

BACKGROUND: The molecular pathomechanisms underlying atrial thrombogenesis are multifactorial and still require detailed investigations. Transgenic mice with cardiomyocyte-directed expression of the transcriptional repressor CREM-IbΔC-X (CREM-TG) represent an experimental model of atrial fibrillation (AF) that shows a gradual, age-dependent progression from atrial ectopy to persistent AF. Importantly, this model develops biatrial thrombi. The molecular characteristics related to the thrombogenesis in CREM-TG mice have not been studied, yet...

Bradycardia, atrial stretch and dilatation, autonomic nervous system disorders, and the presence of triggers such as atrial premature contractions, are factors which predispose a person to paroxysmal AF. Atrial pacing not only eliminates bradycardia but also prevents atrial premature contractions and dispersion of refractoriness, which are a substrate for atrial fibrillation. As the prolonged duration of atrial activation during pacing, especially from locations changing the physiological pattern of this activation (right atrium lateral wall, right atrium appendage), negatively influences both a mechanical and an electrical function of the atria, the atrial pacing site affects an atrial arrhythmogenesis...

BACKGROUND: Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging can be used to evaluate characteristics of atrial fibrosis. The novel noninvasive epicardial and endocardial electrophysiology system (NEEES) allows for the identification of sources with rotor activity. This study describes a new technique to examine the relationship between rotors and LGE signal intensity in patients with persistent atrial fibrillation (PERS) scheduled for ablation. METHODS AND RESULTS: Ten consecutive patients underwent pulmonary vein isolation for persistent atrial fibrillation...

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...

BACKGROUND Percutaneous catheter radiofrequency ablation (RFA) and cryoablation of the left atrium and pulmonary vein ostia have become successful therapeutic modalities in the management of atrial fibrillation. Atrio-esophageal fistula is a rare complication. Awareness of complication risk is imperative because without prompt diagnosis and urgent surgical intervention, the outcome is often fatal. We present 3 cases of atrio-esophageal fistula following percutaneous catheter radiofrequency ablation (RFA). CASE REPORT Case 1: A 72-year old white male presented 27 days after percutaneous RFA for atrial fibrillation with fever, altered mental status, and melena...

INTRODUCTION: Atrial fibrillation (AF) often converts to and from atrial tachycardia (AT), but it is undefined if these rhythms are mechanistically related in such patients. We tested the hypothesis that critical sites for AT may be related to regional AF sources in patients with both rhythms, by mapping their locations and response to ablation on transitions to and from AF. METHODS: From 219 patients undergoing spatial mapping of AF prior to ablation at 3 centers, we enrolled 26 patients in whom AF converted to AT by ablation (n=19) or spontaneously (n=7; left atrial size 42±6cm, 38% persistent AF)...

INTRODUCTION: The right atrium (RA) is readily accessible; however, it is unclear whether changes in the RA are representative of the LA. We performed detailed bi-atrial electroanatomic mapping to determine the electrophysiological relationship between the atria. METHODS AND RESULTS: Consecutive patients with persistent AF underwent bi-atrial electroanatomical mapping with a contact force catheter acquiring points with a CF > 10 g prior to ablation. Points were analyzed for tissue voltage, complex electrograms, low voltage (< 0...

Atrial fibrillation (AF) is a really uncommon arrhythmia in newborns. Here, we report the case of a 1-day-old infant who was recovered in Neonatal Intensive Care Unit for a twin-to-twin transfusion. The appearance of an unexpected AF was registered at his continuous electrocardiographic monitoring. Both chest X-ray and echocardiographic examination revealed the anomalous insertion of the tip of a central venous catheter (CVC) into the heart ('umbilical artery → inferior vena cava → right atrium → patent foramen ovale → left atrium')...

Long lasting or chronic electrophysiological abnormalities in human atria are significant contributors to morbidity during healthy aging. Although both paroxysmal (brief) and chronic atrial fibrillation (AF) were considered to be benign; the notable association between maintained AF and stroke has resulted in AF now being a target for surgical intervention (ablation) and/or drug therapy. An interesting, forward looking paper from the Elinder Group(1) in this issue of Acta Physiologica reveals novel pharmacological agents and principles that could be the basis for more effective antiarrhythmic therapies for AF...

BACKGROUND/AIMS: Recent evidence indicates that peroxisome proliferator-activated receptor (PPAR)-γ activators exert anti-inflammatory and anti-oxidant actions. However, the underlying mechanisms by which these agents prevent atrial remodeling in diabetes are not completely elucidated. We sought to investigate the potential effects of pioglitazone, a PPAR-γ activator, on atrial remodeling and atrial fibrillation (AF) inducibility in diabetic rabbits. METHODS: Alloxan-induced diabetic rabbits were randomly divided into three groups: diabetes only, diabetes treated with low-dose pioglitazone (4 mg/day/kg), or diabetes treated with high dose pioglitazone (8 mg/day/kg) (n = 24 for each group)...

BACKGROUND: Ablation of drivers maintaining atrial fibrillation (AF) has been demonstrated as an effective therapy. Drivers in the form of rapidly activated atrial regions can be noninvasively localized to either left or right atria (LA, RA) with body surface potential mapping (BSPM) systems. This study quantifies the accuracy of dominant frequency (DF) measurements from reduced-leads BSPM systems and assesses the minimal configuration required for ablation guidance. METHODS: Nine uniformly distributed lead sets of eight to 66 electrodes were evaluated...

Electrical remodeling has been reported to play a major role in the initiation and maintenance of atrial fibrillation (AF). Long non-coding RNAs (lncRNAs) have been increasingly recognized as contributors to the pathology of heart diseases. However, the roles and mechanisms of lncRNAs in electrical remodeling during AF remain unknown. In this study, the lncRNA expression profiles of right atria were investigated in AF and non-AF rabbit models by using RNA sequencing technique and validated using quantitative real-time polymerase chain reaction (qRT-PCR)...

Atrial fibrillation (AF) usually manifests as reentrant circuits propagating through the whole atria creating chaotic activation patterns. Little is yet known about how differences in electrophysiological and ionic properties between patients modulate reentrant patterns in AF. The goal of this study is to quantify how variability in action potential duration (APD) at different stages of repolarization determines AF dynamics and their modulation by ionic block using a set of virtual whole-atria human models...

Knowledge of atrial wall thickness (AWT) has the potential to provide important information for patient stratification and the planning of interventions in atrial arrhythmias. To date, information about AWT has only been acquired in post-mortem or poor-contrast computed tomography (CT) studies, providing limited coverage and highly variable estimates of AWT. We present a novel contrast agent-free MRI sequence for imaging AWT and use it to create personalized AWT maps and a biatrial atlas. A novel black-blood phase-sensitive inversion recovery protocol was used to image ten volunteers and, as proof of concept, two atrial fibrillation patients...

Aims: Right atrial (RA) fibrillation (RAF) was previously characterized by initiation from RA ectopies, presence of a right-to-left dominant frequency gradient during atrial fibrillation (AF), and augmentation of the gradient by adenosine triphosphate infusion. We investigated structural characteristics of the bi-atria and epicardial adipose tissue (EAT) volume in patients with RAF. Methods and results: By using multidetector computed tomography, RA, left atrial (LA), right and LA appendage (RAA and LAA, respectively) volumes, pulmonary vein (PV) sizes, and EAT volumes were compared between the RAF group (n = 8) and LA fibrillation (LAF) group (n = 32)...

BACKGROUND: Aberrant vagal stimulation may promote the generation and propagation of atrial fibrillation (AF). Researchers have suggested that botulinum toxin (BTX), a neurotoxin that decreases neural vagal stimulation, may decrease the incidence of postoperative AF. The exact electrophysiologic mechanism underlying the observations and histopathologic alterations associated with BTX are unclear. OBJECTIVE: To investigate the electrophysiologic, functional, and histopathologic effects of BTX on fibrillation induction in ovine atria...

Atropine (ATr) is well known as a cholinergic antagonist, however, at low concentrations ATr could paradoxically accentuate the parasympathetic actions of acetylcholine (ACh). In 22 pentobarbital anesthetized dogs, via a left and right thoracotomy, a leak-proof barrier was attached to isolate the atrial appendages (AAs) from the rest of the atria. In group 1 (Ach+ATr+Ach), ACh, 100 mM, was placed on the AA followed by the application of ATr, 2 mg/mL. The average atrial fibrillation (AF) duration was 17 ± 7 minutes...

BACKGROUND Cardiac lymphoma is a rare entity, defined by the non-extra cardiac location at diagnosis. CASE REPORT Our patient was a 32-year-old female with no particular medical history, who presented with right heart failure with recurrent ascites and pleural effusion. There was a progressive worsening exertional dyspnea. On admission, examination revealed an irregular tachycardia at 170 beats per minute (bpm) and congestive heart failure. The electrocardiogram scored full tachyarrhythmia by atrial fibrillation with an average ventricular rate of 179 cycles per minute...

OBJECTIVE: To investigate whether switching the ablation catheter between the right and left atria through transseptal puncture site can be accurately performed without fluoroscopy. METHODS: Forty patients with persistent atrial fibrillation (mean age, 60.2±7.4 years; 65% males) got "2C3L" approach were randomized in a 1:1 ratio to undergo either crossing interatrial septum guided by fluoroscopy (trackless group) or crossing septum guided by track image that was mapped by Carto3 system (track group)...

OBJECTIVE: Abnormal atrial conduction has been shown to be a substrate for postoperative atrial fibrillation (POAF). This study aimed to determine the relationship between the location of the atrial reentry responsible for POAF, and degree of atrial inflammation. METHODS: Normal mongrel dogs (n = 18) were divided into 3 groups: anesthesia alone (anesthesia), lateral right atriotomy (atriotomy), and lateral right atriotomy with anti-inflammatory therapy (steroid)...