This review focuses on the (mal)adaptive processes in atrial excitation-contraction coupling occurring in patients with chronic atrial fibrillation. Cellular remodeling includes shortening of the atrial action potential duration and effective refractory period, depressed intracellular Ca2+ transient, and reduced myocyte contractility. Here we summarize the current knowledge of the ionic bases u...

Hyperthyroidism has been associated with atrial fibrillation (AF); however, hyperthyroidism-induced ion channel changes that may predispose to AF have not been fully elucidated. To understand the electrophysiological changes that occur in left and right atria with hyperthyroidism, the patch-clamp technique was used to compare action potential duration (APD) and whole cell currents in myocytes f...

AIMS Recent studies reported slowed conduction velocity (CV) in murine hearts homozygous for the gain-of-function RyR2-P2328S mutation (RyR2(S/S)) and associated this with an increased incidence of atrial and ventricular arrhythmias. The present experiments determined mechanisms contributing to the reduced atrial CV. METHODS AND RESULTS The determinants of CV were investigated in murine RyR2(...

inus node disease, atrioventricular conduction disease, atrial brillation, and stroke all have markedly increased incidence in he elderly. Thus, there is frequently an overlap of these onditions. Many patients with pacemakers develop atrial brillation (1–3), and many patients with atrial fibrillation have oncomitant sinus node dysfunction and receive pacemakers. his is not surprising in that th...

progressive endo-epicardial dissociation, transforming the atria into an electrical double layer of dissociated waves that constantly ‘feed’ each other. Figure 1 gives a diagrammatic presentation of the double layer hypothesis. In Figure 1A and B, a rotor is compared with an epicardial breakthrough. Whereas a rotor at best can maintain itself, endo-epicardial breakthroughs act as multiplication...

Objective Mechanisms of pulmonary vein isolation (PVI) for atrial fibrillation remain controversy. This study aimed to investigate the impact of PVI on vagal modulation to atria. Methods Eighteen adult mongrel dogs under general anesthesia were randomly divided into two groups. Bilateral cervical sympathovagal trunks were decentralized and sympathetic effects was blocked by metoprolol administr...

1. Introduction fundamental features that determine whether the atrial tachyarrhythmia becomes atrial flutter or atrial fibrillation There has been a long recognized clinical interrelation-often will be the atrial flutter cycle length, i.e. the cycle ship between atrial flutter and atrial fibrillation. Patients length of a stable atrial reentrant circuit which develops. If who primarily manifes...

BACKGROUND Therapeutic decisions in atrial fibrillation (AF) are often influenced by assessment of bleeding risk. However, existing bleeding risk scores have limitations. OBJECTIVES We sought to develop and validate a novel bleeding risk score using routinely available clinical information to predict major bleeding in a large, community-based AF population. METHODS We analysed data from Out...

Ranolazine has been shown to produce atrial-selective depression of sodium channel-dependent parameters and suppress atrial fibrillation (AF) in a variety of experimental models. The present study contrasts the effects of ranolazine and those of a clinically used anti-AF class IC agent, propafenone. Electrophysiological and anti-AF effects of propafenone and ranolazine were compared at clinical...

AIMS Contemporary ionic-based membrane models are computationally expensive and are not intended to match the properties of a given experimental preparation. The aim of this work was to use measured restitution properties of electrically remodelled atrial tissue to develop a simplified membrane model based on the Fenton-Karma (FK) equations amenable to large-scale simulation of chronic atrial f...