A first-degree, or 1 st degree, AV block is indicated on the ECG by a prolonged PR interval, as seen below. Recall that the P wave indicates atrial depolarization, initiated by firing of the SA node.

Various maneuvers can be employed to distinguish between the two potential rhythms when an ECG reveals 2:1 AV nodal block: Carotid sinus massage or adenosine: This slows the sinus rate ...

that was obtained twice a day or by ECG that was obtained in case of bradycardia-related symptoms. Permanent PM was implanted for all of the patients with recurrence or persistence of AV block ...