Tags: Disease.
An atrioventricular block (or AV block) involves the impairment of the conduction between the atria and ventricles of the heart. Under normal conditions SA node in the atria sets the pace for the heart and these impulses travel down to the ventricles. In an AV block this message does not reach the ventricles or is impaired along the way. The ventricles of the heart have their own pacing mechanisms which can maintain a lowered heart rate in the absence of SA stimulation.