[Bradyarrhythmia]

Bradyarrhythmia has been well studied, and many results contributed to the progress of its treatments. When simple pacemaker like VVI was first invented, it seemed to have solved the problem, but the pacemaker did not improve the mortality rate until physiological pacing like DDD was invented. Permanent pacemaker implantation has now become standard means to solve the problem whether it was due to sinus node dysfunction or conduction disturbances. Recent trend of arrhythmia study has already been shifted to be focused on tachyarrhythmia, especially related to RF ablation. This new technique has revealed many informations related to mechanism of tachyarrhythmias, and also the basic functional structure of AV node and other cardiac conduction system. Such informations gave many knowledges about bradyarrhythmia. On the other hand, study on autonomic nervous system is not yet enough to unveil its role.