Diet induced obese (DIO) mice display both increased susceptibility to inducible atrial fibrillation (AF) and an overall increase in reactive oxygen species (ROS) production specific the cytosol mitochondria. NADPH oxidase 2 (NOX2), a major source of cytosolic ROS human atria, has been implicated ion channel remodeling leading AF independent obesity is significantly atria DIO mice. Although tre...

Experiments were performed on the hearts of open-chest anesthetized dogs and on isolated rabbit hearts. Intracellular microelectrodes and bipolar surface electrodes were used for recording from and for stimulating the atria, AV node, bundle of His, bundle branches and ventricles. Atrial or ventricular premature beats which were usually blocked or delayed within the AV node were facilitated when...

Arterial baroreflex control of the heart and peripheral circulation is markedly impaired in humans and animals with congestive heart failure. After reversal of heart failure in animal models, arterial baroreflex control of heart rate remains impaired for up to 8 months. Cardiac transplantation restores normal ventricular function and completely reverses heart failure, but does it normalize arte...

Isolated superfused rat atria release [H]acetylcholine when depolarized with 57 mM potassium. The depolarization-induced overflow of [H]acetylcholine is markedly inhibited by micromolar concentrations of epinephrine and norepinephrine. The a,-selective adrenergic agonist methoxamine also inhibits tritium overflow, but the «2-selective adrenergic agonist clonidine and the 0-adrenergic agonist is...

Atria from mice fed a selenium-deficient (Se(-)) diet have a diminished beta-adrenoceptor-inotropic cardiac response to isoproterenol or norepinephrine compared with atria from mice fed the same diet supplemented with 0.2 mg/kg Se as sodium selenite (Se(+)). This diminished response could be reversed by feeding Se(-) mice the Se(+) diet for 1 wk or by pretreatment with nitric oxide synthase (NO...

Introduction Atrial fibrillation (AF) is the most common arrhythmia in humans. Its maintenance is thought to be due to multiple wavelets reentry occurring in both atria [1]. Previous studies have demonstrated the feasibility and efficacy of cryoablation to create lesions in both atria [2] and on the posterior wall of the left atrium [3], connecting the four pulmonary veins and the mitral annulu...

The heart is heavily innervated with sympathetic and parasympathetic nerve fibers. Although both receptor types are present in the atria and ventricles, the cholinergic receptors are located mainly in the atria and the adrenergic receptors in the ventricles. The distribution of these receptors in the ventricles is not homogenous but follows apex-to-base and epicardium-to-endocardium gradients. ...

The regulation of body fluid volumes has long been a puzzle. For example, what factors are involved in correcting the volume expansion during and following the intravenous infusion \ of isotonic saline? In other words, how is the blood volume maintained and the “milieu interieur” kept within narrow limits? Several factors such as aldosterone, the antidiuretic hormone arginine vasopressin, and o...

Transthoracic and transoesophageal cardiac echocardiography and Doppler investigations were performed in 31 consecutive patients with malignant midgut carcinoid tumours. The transoesophageal images allowed measurement of the thickness of the atrioventricular valve leaflets and the superficial wall layers on the cavity side of both atria. The mean thickness of the anterior tricuspid leaflet was ...

These studies were designed to examine the electrophysiological effects of diphenylhydantoin (Dilantin) on the heart of awake dogs. Recording electrodes were implanted over the sinoatrial node, bundle of His, and right bundle branch, and studies were performed 2 to 6 weeks following recovery. Diphenylhydantoin (10 mg/kg) increased heart rate, shortened A-V conduction time and had little or no e...