Arrhythmias

Question 1

What are common arrhythmias?

Answer 1

Bradycardia
Atrial flutter
Atrial fibrillation 
Tachycardia
Ventricular fibrillation

Question 2

What can cause tachycardia?

Answer 2

Ectopic pacemaker activity

• damaged areas of myocardium - become depolarised
• latent pacemaker region activated due to ischaemia

Afterdepolarisations
- abnormal depolarisations

Atrial flutter/fibrillation

Re-entry loop
- conduction delay

Question 3

What can cause bradycardia?

Answer 3

Sinus bradycardia

• sick sinus syndrome (SA node dysfunction)
• drugs

Conduction block

• problems at AV node or bundle of HIs
• slow conduction at AV node

Question 4

What are delayed after-depolarisations?

Answer 4

Triggered activity after repolarisation

Question 5

What can cause delayed after-depolarisations?

Answer 5

High intracellular calcium

Question 6

What are early after-depolarisations?

Answer 6

Depolarisations during repolarisation stage

Question 7

What is the re-entrant mechanism?

Answer 7

Incomplete conduction damage

Excitation takes long route (often slower) through damaged area

Question 8

What is AV nodal re-entry?

Answer 8

Fast and slow pathways in AV node create re-entry loop

Question 9

What is ventricular pre-excitation?

Answer 9

Accessory pathway between atria and ventricles creates re-entry loop

Question 10

What is Wolff-Parkinson-White syndrome?

Answer 10

Condition with extra pathways between atria and ventricles