Atrial and ventricular cardiac chambers behave as distinct subunits with unique morphological, electrophysiological and contractile properties. Despite the importance of chamber-specific features, chamber fate assignments remain relatively plastic, even after differentiation is underway. In zebrafish, Nkx transcription factors are essential for the maintenance of ventricular characteristics, bu...

BACKGROUND Cardiac arrhythmias as a late complication following congenital heart surgery are encountered more and more frequently in clinical practice. The use of new electrophysiological methods of visualisation and mapping improves the efficacy of radio-frequency (RF) ablation of these arrhythmias. AIM To assess patterns of atrial arrhythmias following congenital heart surgery and to examin...

OBJECTIVE To investigate the characteristics of ectopic automaticity and cation current (I(f)) of cardiac myocytes from pulmonary vein sleeves (PVs) in canines with atrial fibrillation. METHODS The canines (8-10 years old) were subjected to long-term, rapid atrial pacing (RAP) for 10 weeks, which induced the atrial fibrillation model. Disassociation of PVs of canines yielded single cardiac my...

The effects of intravenous diphenylhydantoin (5 mg/kg) on atrioventricular conduction in man at controlled heart rates in the digitalized and undigitalized state were studied. In undigitalized subjects, diphenylhydantoin administration consistently decreased A-V conduction time in each individual subject when identical heart rates were compared. Ouabain infusion produced an increase in A-V cond...

The electrocardiogram was monitored in 51 patients during fiberoptic bronchoscopic procedures and was compared to recordings made before premedication. Sixteen of the patients had heart disease. During the bronchoscopic procedure, the heart rate increased by 154 "/- 5 percent (+/- SE). The frequency of atrial ectopic beats was minimally increased, by an average 0.15 +/- 0.12 beats per minute (n...

Family physicians frequently encounter patients with symptoms that could be related to cardiac arrhythmias, most commonly atrial fibrillation or supraventricular tachycardias. The initial management of atrial fibrillation includes ventricular rate control to provide adequate cardiac output. In patients with severely depressed cardiac output and recent-onset atrial fibrillation, immediate electr...

Introduction Atrial fibrillation (AF) is the most common significant cardiac arrhythmia, affecting an estimated four million people worldwide. Its rapid and uncoordinated atrial rhythm significantly compromises hemodynamics, decreases cardiac output, predisposes to ventricular arrhythmias, and sets the stage for thromboembolic complications. Contributing mechanisms are presumed to be the occurr...