atrioventricular block AE second degree atrioventricular block AE Ⅱ度房室传导阻滞 MedDRA: 10003677 SS second degree heart block an atrioventricular block AE that some but not all atrial impulses fail to reach the ventricles, thus some ventricular beats are dropped. Electrical signals between the atria and ventricles are slowed to a large degree. Some signals don't reach the ventricles. On an EKG, the pattern of QRS waves doesn't follow each P wave as it normally would. atrioventricular block second degree 二度房室传导阻滞