Interpret the following rhythm:

A) First-degree AV block
B) Second-degree AV block Mobitz I (Wenckebach phenomenon)
C) Second-degree AV block Mobitz II
D) Third-degree AV block (complete heart block)

Question

Interpret the following rhythm:

A) First-degree AV block 
B) Second-degree AV block Mobitz I (Wenckebach phenomenon) 
C) Second-degree AV block Mobitz II 
D) Third-degree AV block (complete heart block)

Quizplus · Accepted Answer

Third-degree block is often called complete heart block because no atrial impulses are conducted through the AV node to the ventricles.In complete heart block,the atria and ventricles beat independently of each other because the AV node is completely blocked to the sinus impulse and it is not conducted to the ventricles.One hallmark of third-degree heart block is that the P waves have no association with the QRS complexes and appear throughout the QRS waveform.Second-degree AV block type II (Mobitz II)is a more critical type of heart block that requires early recognition and intervention.There is no progressive lengthening of the PR interval,which remains the same throughout with the exception of the dropped beat(s).Also called a Mobitz I or Wenckebach phenomenon,second-degree AV block type I is represented on the ECG as a progressive lengthening of the PR interval until there is a P wave without a QRS complex.In first-degree AV block,a P wave precedes every QRS complex,and every P wave is followed by a QRS.

Interpret the Following Rhythm