Impulse initiation and conduction in the murine atria: a basis for future investigation of sinus node dysfunction.

The prevalence of atrial conduction defects and sinus node dysfunction increases with age. These age-related changes may play a critical role in establishing the substrate for the development of atrial fibrillation (AF), the most common sustained arrhythmia. Despite the association between atrial arrhythmias and age, little is known of the mechanisms that underlie changes in atrial electrophysiological function. Ongoing studies in our laboratory are focused on determining the mechanisms of atrial conduction defects associated with aging and disease. The purpose of this report is to present some initial studies of the murine sinus node and the approach we have taken to quantify conduction at the site of impulse initiation.