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.

A first-degree AV block is indicated on the ECG by a prolonged PR interval. Recall that the P wave indicates atrial depolarization (initiated by firing of the SA node). The atrial depolarization ...

Less than 5% of patients developed first-degree AV block or intraventricular conduction ... and narrow QRS Constant PR interval preceding blocked P PR increment (Wenckebach) preceding a blocked ...

Second-degree AV block PR increment preceding a blocked P (Wenckebach) and narrow QRS Constant PR interval preceding blocked P PR increment (Wenckebach) preceding a blocked P and wide QRS 2:1 AV ...