Bradyarrhythmias

Question 1

Sick Sinus Syndrome

Answer 1

Due to sinus node dysfunction

Pace if symptomatic

Question 2

1st Degree Heart Block - ECG

Answer 2

Impulse is conveyed slowly through the AV node

Bradycardic, lengthened PR interval (>0.20 seconds)

Question 3

1st Degree Heart Block - Causes

Answer 3

AV nodal disease

Enhanced vagal tone (athletes)

AMI

Electrolyte imbalance

Drugs

Question 4

2nd Degree Heart Block - Mobitz Type 1

ECG

Answer 4

Bradycardic, progressive prolongation of the PR interval followed by a dropped QRS

Question 5

2nd Degree Heart Block - Mobitz Type 2

ECG

Answer 5

Progressive prolongation of the PR interval with occasional dropped QRS beats

Ratio block, e.g. 2:1, 3:1, etc.

Question 6

2nd Degree Heart Block

Answer 6

Some P waves conduct through the AV node but others do not

Causes include AV nodal disease and AMIs

Question 7

3rd Degree Heart Block - ECG

Answer 7

Ventricular rate is slower than the atrial

No relationship between the P wave and QRS

Question 8

3rd Degree Heart Block

Answer 8

Blockage in the conduction system

Causes include AMI, congenital, progressive degradation of the conduction system and endocarditis

Pacing is required