Chapter 6 Atrioventricular Blocks ECG Chapter 6 Atrioventricular Blocks

First-Degree AV Block – pg. 61 Delay in the conduction from the atria to the ventricles. With first degree blocks, every PR interval is >0.20 seconds or 5 boxes in length. Every “p” wave causes a “QRS” or every atria depolarization reaches the ventricles.

So what is this?

Second-Degree AV Block Type I (Mobitz Type I, or Wenckebach), pg. 62-63

P to QRS Ratio The ratio may remain constant or vary. Pg. 62-63

What’s This?

Second-Degree AV Block Type II (Mobitz Type II) 3:1 2:1

What is this?

Third-Degree AV Block

Third-Degree AV Block Idioventricular rhythm pacing the ventricles Junctional escape rhythm pacing the ventricles Complete dissociation between the atria and ventricles or complete heart block. Atria are depolarizing but not conducting to ventricles so another pacemaker must take over in the ventricles. True 3rd degree heart block will have the atria rate > the ventricular rate.

Complete dissociation between the atria and ventricles or complete heart block. Atria are depolarizing but not conducting to ventricles so another pacemaker must take over in the ventricles. True 3rd degree heart block will have the atria rate > the ventricular rate.

AV Dissociation: Ventricular rate is faster than the arial rate. Transient, non – lethal condition