Chapter 8

Question 1

Types of Atrio Ventricular(AV) blocks

Answer 1

First degree heart block

Second degree type I (Wenckeback)

Second degree Type II ( Mobitz type II)

Third degree heart block ( AV dissociation)

Question 2

First degree heart block

Answer 2

Characteristics:

elongated PR interval

Clinical significance:

benign by itself

usually caused by coronary artery disease causing AV nodal ischemia

Management:

Treat underlying cause

Digoxin

Question 3

Second degree Type I (Wenckeback)

Answer 3

Characteristics:

Periodic conduction failure within AV node

PR interval to progressively lengthen until QRS complex is dropped

Grouped beats called footprint of Wenckebach

Clinical significance:

same as first degree

Patients may need transcutaneous or transvenous pacing

Management:

close observation

Question 4

Second degree Type II (Mobitz Type II)

Answer 4

Characteristics:

Regular rhythm with constant PR interval from beat to beat until a sudden drop of complete QRS complex

Likely to progress to 3rd degree, needs immediate attention

Clinical significance:

Usually caused by hypoxia, myocardial infarction, conduction system disturbances

Management:

Responds better with epinephrine than atropine