Aging-Related Changes Of Atrial Sleeves In Canine

Atrial fibrillation (AF) is now recognized to be main antiarrhythmia target in the new millennium as it increases morbidity and mortality in prevalence with age. Based on the current knowledge, most of paroxysmal atrial fibrillation (PAF) were initiated by ectopic beats originating from the pulmonary veins, the superior vena cava and upper portion of the crista terminalis.The clinical studies showed 90% ectopic beats originating from the myocadial sleeves which extend from left atrium and circle pulmonary veins.The fact that elimination of ectopic foci originating from the pulmonary myocadial sleeves by radiofrequency ablation is established as a curative treatment for some patients with PAF might demonstrate the pulmonary myocadial sleeves being responsible for AF initiation. Clinical epidemiologic survey showed that the prevalence of AF increases with aging, but few studies were refered to the relationship of AF initiation and aging-related changes of atria, especially, aging-related changes of myocadial sleeves. So the studies of aging-related changes in electrophysiologic properties of myocadial sleeves might offer the experimental evidence whether aging is primary or independent factor contributing to AF incidence.The electrophysiologic properties of pulmonary veins, superior vena cava, two atriums and coronary sinus in old and adult dogs were detected through atrial transseptal procedure and catheter technique and the AF thresholds at different sites...