Atrial dispersion of refractoriness.

In contrast to the ventricular myocardium, until recently the electrophysiologic properties of the human atrium had been studied less intensively. Since new, highly effective therapeutic strategies have become available, both clinical and experimental research has been focused on atrial arrhythmias. Experimental data suggest that shortening of the refractory periods and increased dispersion of refractoriness between adjacent areas of the atrium are characteristic for paroxysmal atrial fibrillation. The duration and frequency of atrial fibrillation episodes seem to be associated with persistent electrophysiologic alteration of the atrium. The influence of the autonomic nervous system, antiarrhythmic drugs, and circadian differences also could play a role in the genesis of atrial arrhythmias.