All ECG 25
- Normal sinus rhythm
- Two to one AV nodal block (2:1 AV nodal block)
- Right bundle branch block
2:1 AV block is a form of second degree AV nodal block and occurs when every other P wave is not conducted through the AV node to get to the ventricles and thus every other P wave is NOT followed by a QRS complex. Below is an image from a different ECG demonstrating 2:1 AV nodal block:
2:1 AV block can possibly be from either second degree type I AV nodal block (Wenckebach) or second degree type II AV nodal block. This distinction is crucial since the former is usually benign while the later requires implantation of a permanent pacemaker. Click the 2:1 AV Nodal Block Review button below for more details on how to make this distinction.