Heart Block

Question 1

First degree heart block?

Answer 1

PR interval > 0.2 seconds

Question 2

Second degree heart block Type 1 (Mobtiz 1, Wenckebach)?

Answer 2

Progressive prolongation of the PR interval until a dropped beat occurs

Question 3

Second degree heart block Type 2 (Mobtiz 2)?

Answer 3

PR interval is constant but the P wave is often not followed by a QRS complex

Question 4

Third degree heart block (complete)?

Answer 4

Where P waves (atrial depolarizations) are completely unrelated to the QRS complexes (ventricular depolarizations) ― meaning the P waves occur at one rate and the QRS complexes at another. This is termed “AV dissociation.”

Question 5

Features of heart block?

Answer 5

• syncope
• heart failure
• regular bradycardia (30-50 bpm)
• wide pulse pressure
• JVP: cannon waves in neck
• variable intensity of S1