Atrial fibrillation

Question 1

What is atrial fibrillation?

Answer 1

Electrical impulse no longer generated from SA node

Lots of small electrical impulses generated which cause the atria to contract in a disorganised manner

Question 2

How does this appear on an ECG

Answer 2

P wave no longer present as this indicates atrial depolarisation
QRS complexes at irregular intervals
HR >100bpm

Question 3

Causes/ risk factors

Answer 3

Hypertension 
Valve disease
CAD
alcoholism 
genetic 
male
This cause a stretch in the atrial wall cells

Question 4

How doe Atrial fibrillation develop

Answer 4

• stress in the atria walls
• leads to tissue heterogeneity: different cells have different properties e.g. some conduct slower, some have longer refractory periods
• this can lead to fibrosis ie inability to conduct

Question 5

Different types of AF and how they are monitored

Answer 5

Blood tests
Paraoxymal AF- episodes once a week- can be monitored with ambulatory monitoring
Persistant- when cells present with lots of fibrosis- monitored with an ECG

Question 6

Symptoms

Answer 6

• Asymptomatic
• chest pain
• shortness of breath
• palpitations
• dizziness
• fatigue

Question 7

Complications of AF

Answer 7

Embolism
stroke
stagnant blood in the atria can lead to the development of clots which can then make their way to the brain

Question 8

Treatment

Answer 8

Rate control: digoxin, beta blockers, calcium channel antagonists
OR direct current cardio version- if AF experienced for more than 48 hours the patient has to be on blood thinners before and after
Antiarrythmic drugs: IC- sodium blocker , III- potassium channel blocker
Rhythm control: pacemaker and ablation

Question 9

What is ablation, MAZE procedures and examples

Answer 9

the destruction of areas of tissue so electrical signal cannot pass through them e.g. AV ablation
MAZE procedure: new pathways developed by causing ablation through other tissues