Many dietary supplements promise to improve physical and mental functioning, but caffeine, an age-old food component, is one of the few that delivers. Caffeine makes its consumers awake and alert, and it improves performance (1). Therefore, coffee could be called a functional food. But is it safe? If coffee were discovered today, it would probably be regarded, in the European Union’s terminolog...

BACKGROUND The development of selective atrial antiarrhythmic agents is a current strategy for suppression of atrial fibrillation (AF). METHODS AND RESULTS Whole-cell patch clamp techniques were used to evaluate inactivation of peak sodium channel current (I(Na)) in myocytes isolated from canine atria and ventricles. The electrophysiological effects of therapeutic concentrations of ranolazine...

BACKGROUND There is a critical need for safer and more effective pharmacological management of atrial fibrillation (AF) in the setting of heart failure (HF). METHODS AND RESULTS This study investigates the electrophysiological, antiarrhythmic, and proarrhythmic effects of a clinically relevant concentration of ranolazine (5 μmol/L) in coronary-perfused right atrial and left ventricular prepar...

BACKGROUND Accurate risk stratification is considered the first and most important step in the management of patients with non-valvular atrial fibrillation (NVAF). We compared the performance of the widely used CHA2DS2-VASc and the recently developed R2CHADS2 and ATRIA scores, for predicting thromboembolic (TE) event in either non-anticoagulated or anticoagulated patients with NVAF. METHODS T...

BACKGROUND Structural remodeling of human atria plays a key role in sustaining atrial fibrillation (AF), but insufficient quantitative analysis of human atrial structure impedes the treatment of AF. We aimed to develop a novel 3-dimensional (3D) structural and computational simulation analysis tool that could reveal the structural contributors to human reentrant AF drivers. METHODS AND RESULT...

Background Atrial electrical remodeling(AER) plays an important role in the pathogenesis and maintenance of atrial fibrillation. However, little is known about modulation of vagal activity to AER. This study aimed to investigate the relationship between vagal moduation and AER. Methods Twenty four adult mongrel dogs under general anesthesia were randomized into 3 groups. Sympathetic activity wa...

Atrial fibrillation (AF) is known to cause significant changes in atrial tissue architecture and atrial electrophysiology (1). In recent years, it has become clear that preexisting alterations (autonomic dysbalance, degenerative tissue changes, fibrosis, and so forth) can provide an electrophysiologic and morphologic substrate, which increases the likelihood of AF onset in response to triggerin...

Methods 44 consecutive patients with normal left ventricular ejection fraction (LVEF> 35%), age<70 years old, were enrolled in a research study exploring the underlying myocardial substrate of ECG findings. The presence of interatrial fat was assessed with a complete CMR study including Dark-blood DIR-prepared Fat-Water-separated sequence3 in the horizontal longitudinal axis (4 chamber view). T...

Current advanced technology allows the accurate three-dimensional reconstruction of cardiac structures using multiple images from two-dimensional intracardiac echocardiography (ICE). This technology is applicable to atrial fibrillation (AF) ablation and provides real-time anatomical information on relevant atrial structures and myocardial thickness as well as suitable sites for transseptal punc...

In this issue of the Circulation: Arrhythmia and Electrophysiology, Kurotobi et al1 determined the number of arrhythmogenic foci in atria provocable with isoproterenol infusion in patients with paroxysmal, persistent, and permanent atrial fibrillation (AF). The results show that persistent AF has more foci than paroxysmal AF. However, when AF persists for 12 months, the number of foci were redu...