Age- and sex-related atrial electrophysiologic and structural changes.

Age and gender dependence of the 3 major variables--left atrial (LA) dimension, effective refractory period (ERP), and atrial conduction--that govern the development of atrial fibrillation (AF) were examined in 76 women and 39 men without structural heart disease. A significant positive correlation was found between age and LA dimension, mainly because of a strongly positive correlation in women not taking hormone replacement therapy but not in women on hormone replacement therapy. Men had a significantly greater average LA dimension than women. Neither ERP nor atrial conduction estimated by normalized P-wave duration demonstrated any significant correlation with either age or gender. It was concluded that LA size is greater in the elderly and in men, which may increase their risk for AF.