Heart Block

Question 1

First Degree AV Block

Answer 1

Regular
Rate: Varies
P Wave: P, U, 1:1
PRI: >0.2
QRS: ≤0.12
Must identify the underlying rhythm
No dropped QRS
IDENTIFIED BY A PRI LONGER THAN 0.2 SECONDS

Question 2

2nd Degree Type 1 AV Block

Answer 2

Mobitz 1, Wenckebach

Irregularly Regular
Rate: A: 60-100, V: Varies
P Wave: P, U, Not 1:1
PRI: Varies, Increasing pattern
QRS: ≤0.12

Dropped QRS after lengthening PRI
Longer, longer, longer, …., drops

Question 3

2nd Degree Type 2 AV Block

Answer 3

Mobitz 2

Regular but interrupted
Rate: A: 60-100, V: Varies
P Wave: P, U, Not 1:1
PRI: 0.12-0.2
QRS: ≤0.12

Multiple dropped QRS
PRI is constant

Question 4

3rd Degree AV Block