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Atrial fibrillation (AF) is the most common arrhythmia in clinical practice. It can occur at any age but is very rare in children and becomes extremely common in the elderly, with a prevalence approaching 20% in patients 85 years of age.1 AF is associated with a wide range of potential complications and contributes significantly to population morbidity and(More)
BACKGROUND The molecular mechanism of increased background inward rectifier current (IK1) in atrial fibrillation (AF) is not fully understood. We tested whether constitutively active acetylcholine (ACh)-activated I(K,ACh) contributes to enhanced basal conductance in chronic AF (cAF). METHODS AND RESULTS Whole-cell and single-channel currents were measured(More)
BACKGROUND Congestive heart failure (CHF) is a common cause of atrial fibrillation. Focal sources of unknown mechanism have been described in CHF-related atrial fibrillation. The authors hypothesized that abnormal calcium (Ca(2+)) handling contributes to the CHF-related atrial arrhythmogenic substrate. METHODS AND RESULTS CHF was induced in dogs by(More)
BACKGROUND Delayed afterdepolarizations (DADs) carried by Na(+)-Ca(2+)-exchange current (I(NCX)) in response to sarcoplasmic reticulum (SR) Ca(2+) leak can promote atrial fibrillation (AF). The mechanisms leading to delayed afterdepolarizations in AF patients have not been defined. METHODS AND RESULTS Protein levels (Western blot), membrane currents and(More)
RATIONALE Understanding atrial fibrillation (AF) requires integrated understanding of ionic currents and Ca2+ transport in remodeled human atrium, but appropriate models are limited. OBJECTIVE To study AF, we developed a new human atrial action potential (AP) model, derived from atrial experimental results and our human ventricular myocyte model. (More)
Sinus node dysfunction (SND) is a major public health problem that is associated with sudden cardiac death and requires surgical implantation of artificial pacemakers. However, little is known about the molecular and cellular mechanisms that cause SND. Most SND occurs in the setting of heart failure and hypertension, conditions that are marked by elevated(More)
Atrial fibrillation (AF) is an extremely common cardiac rhythm disorder that causes substantial morbidity and contributes to mortality. The mechanisms underlying AF are complex, involving both increased spontaneous ectopic firing of atrial cells and impulse reentry through atrial tissue. Over the past ten years, there has been enormous progress in(More)
Sphingosine-1-phosphate (SPP) and sphingosylphosphorylcholine (SPPC) have been reported to activate muscarinic receptor-activated inward rectifier K(+) current (I(K.ACh)) in cultured guinea pig atrial myocytes with similar nanomolar potency. Members of the endothelial differentiation gene (Edg) receptor family were recently identified as receptors for SPP;(More)
This review is focused on electrical adaptational processes in patients with chronic AF. Cellular electrical remodeling includes shortening of action potential duration and effective refractory period that can be explained by concomitant alterations in ion channel activity. While most currents studied are reduced or unaffected, the inward rectifier I(K1) is(More)