In second-degree type II AV nodal block (a.k.a. Mobitz Type II AV block), the AV node becomes completely refractory to conduction on an intermittent basis. For example, three consecutive P waves ...

and Mobitz type 2, which can cause problems pumping blood and irregular heartbeats. Heart blocks are disruptions in the electrical signals that regulate and coordinate movements of the heart ...

In second-degree atrioventricular nodal block — also known as Wenckebach block or Mobitz Type I AV block ... This is called 2:1 AV block, as depicted below: When 2:1 AV block is present ...