Atrial Fibrillation

Question 1

What is atrial fibrillation

Answer 1

Type of arrhythmia causing the heart to pump less effectively

Question 2

Supraventricular arrythmia

Answer 2

It originates in the atria
> Rapidly discharging ectopic foci
> Atria rhythm irregular (300-500bpm)
> AV node limits the number of impulses that reach the ventricles
> Ventricular rate is not as fast

Question 3

Consequences of AF

Answer 3

> Reduction in cardiac output leading to heart failure
Thrombosis which can dislodge and form strokes and systemic embolisms

Question 4

Symptoms of AF

Answer 4

Palpitations
Shortness of breath
Tiredness/fatigue
Generalised weakness
Poor exercise tolerance
Irregular pulse
Dizziness

Question 5

Classification

Answer 5

Paroxysmal: Spontaneous termination, <7 days, 2 or more episodes
Persistent: Non-self terminating, requires electrical or pharmacological termination, 2 or more episodes
Permanent: Not successfully terminated with cardioversion and longstanding >1 year

Question 6

Rate control

Answer 6

Beta blocker (excluding sotalol)
OR
Calcium channel blocker (diltiazem [off label] or verapamil)

Digoxin is only considered for non-paroxysmal AF is patient is sedentary

If monotherapy does not work, consider combination therapy with any of the 2:
> Beta blocker
> Diltiazem (not verapamil)
> Digoxin

Question 7

Beta blockers

Answer 7

Acts on beta 1 receptors:
- Reduce SAN automaticity reducing sinus rate
- Reduces conduction velocity
- Inhibits apparent pacemaker activity

For people with AF alone: atenolol 50-100mg
For people with HF: Bisoprolol, carvedilol or Nebivolol
For people with DM: A cardioselective beta blocker

Question 8

Diltiazem and verapamil

Answer 8

Bind to L-type calcium channels
- Blocks calcium entry
- Decreased myocardial force of contraction (negative inotropy)
- Decreased heart rate (negative chronotropy)
- Decreased conduction velocity (negative dromotropy)

Question 9

Antiarrhythmic drug classification

Answer 9

Class I - Na+ channel blockers
Class II - Beta adrenoceptor antagonists
Class III - K+ channel blockers
Class IV - Ca2+ channel antagonist

Question 10

Long term rhytm control:

Answer 10

1st choice: beta blocker
2nd choice: Flecainide or Propafenone ( suitable if no ischaemic heart disease or congestive heart failure)
2nd choice: Dronedarone (suitable if no LV systolic dysfunction or CHF)
2nd choice: Amiodarone (suitable if LVSD or CHF present)

Question 11

Pill-in-pocket

Answer 11

For paroxysmal AF with no history of ventricular dysfunction or ischaemic heart disease. Have a history of infrequent symptomatic episodes. Systolic BP >100mg and resting heart rate >70bpm

Flecainide 300mg
Propafenone 600mg
Take dose if AF is longer than 5 minutes
If it doesn’t revert within 6-8 hours or new symptoms develop then go hospital

Question 12

Anticoagulant

Answer 12

Assess stroke and bleeding risk
- Do not offer aspirin monotherapy
- Apixaban, dabigatran, rivaroxaban, warfarin