Background Atrial Fibrillation (AF) is a heart condition characterized by chaotic electrical activity and irregular contractions in the atria. AF is a progressive disease with three stages of increasing fibrillation duration and frequency: paroxysmal, persistent, and permanent. Studies show that as AF progresses, there is a significant increase in left atrial (LA) volume correlated with structu...

Atrial fibrillation, a common cardiac arrhythmia, often progresses unfavourably: in patients with long-term atrial fibrillation, fibrillatory episodes are typically of increased duration and frequency of occurrence relative to healthy controls. This is due to electrical, structural, and contractile remodeling processes. We investigated mechanisms of how electrical and structural remodeling cont...

tistics Committee and Stroke Statistics Subcommittee. Executive summary: heart disease and stroke statistics—2012 update: a report from the American Heart Association. Circulation. 2012;125(1):188-197. 2. Go AS, Hylek EM, Phillips KA, et al. Prevalence of diagnosed atrial fibrillation in adults: national implications for rhythm management and stroke prevention: the AnTicoagulation and Risk Fact...

BACKGROUND The Maze procedure in patients without mitral valve disease remains controversial, because of the increased invasiveness and operation time required to create additional incisions in the atria. The aim of this study was to assess prognosis following the Maze procedure in patients without mitral valve disease. METHODS AND RESULTS One hundred and seven consecutive patients who underw...

Invasive electrophysiologic studies have changed the clinical outlook for patients with atrial flutter. Recognition of the reentrant circuit responsible for typical atrial flutter has led to the development of catheter ablation techniques that can prevent recurrence in >90% of cases. In addition, general understanding of atrial tachycardias has changed radically, such that ECG-based classificat...

The incidence of atrial fibrillation increases with age, but it is unknown whether there are changes in the intrinsic function of Na+ currents in cells of the aged atria. Thus, we studied right (RA) and left (LA) atrial cells from two groups of dogs, adult and aged (>8 yr), to determine the change in Na+ currents with age. In this study all dogs were in normal sinus rhythm. Whole cell voltage c...

Flecainide and other class IC antiarrhythmic drugs are effective in the prevention and termination of atrial fibrillation, but the mechanism of this action is unknown. To gain insights into potential cellular mechanisms, we evaluated the response of human atrial action potentials to equimolar therapeutic concentrations of flecainide and quinidine and compared this response to that of guinea pig...

BACKGROUND The junction between the coronary sinus (CS) musculature and both atria contributes to initiation of atrial tachyarrhythmias. The current study investigated the effects of CS isolation from the atria by radiofrequency catheter ablation on the induction and maintenance of atrial fibrillation (AF). METHODS AND RESULTS Using an optical mapping system, we mapped action potentials at 25...

• The mechanism of irregular ventricular responses to atrial fibrillation has not been established. If atrioventricular transmission occurred via a single path with uniform properties, ventricular cycle lengths would be governed by the refractory period of the path and the temporal pattern of the input supplied by the fibrillating atria. Since the frequency of stimuli available to the A-V condu...