AF

Question 1

Anticoagulation

Answer 1

Embolic events similar in rate or rhythm control
If chadsvasc >2
Aspirin NOT recommended if low risk
Risk of stroke/yr roughly equal to chadsvasc score up to 4 then increases

If cardioverting and AF present > 48hrs, pre cardioversion anticoag required ( unless TOE done to exclude thrombus)

All cardioverted pts to be anticoagulated for 4 wks post

Question 2

Types of AF

Answer 2

Paroxysmal
Persistent > 7 days
Chronic, failed cardioversion > 1yr

Question 3

Causes of AF

Answer 3

Substrate vs electrical triggers

Substrate AF

• incr LA stretch- ie mitral valve disease
• incr LA pressure ie HTN, diastolic dysfunction
• LA fibrosis - ie stretch, pressure, ischemia
• upset of autonomic input into LA- vagally induced ie post heavy meal

Electrical/ trigger AF

• any rapid atrial arrhythmia
• incr PV stretch, pressure, fibrosis ie PV anomalies in young ppl
• upset of autonomic input into PV

Reversible/ acute physiological insults

• hyperthyroid
• cardiac surgery
• PE/ respiratory disease
• sepsis
• OSA

Irreversible

• HTN
• Structural heart disease/ valvular
• ischaemia
• Heart failure
• aging
• diabetes

Question 4

Rate control

Answer 4

Aim HR 80

B blocker: block sinus node and AV conduction
Non di hydropyridine CCB in ppl with lung disease (verapamil, diltiazem): increases refractoriness slows AV conduction. Avoid in LV dysfunction coz neg inotrope
Mg

Question 5

Rhythm control

Answer 5

No survival advantage or reduction in stroke risk wit restoration and maintenence of SR (AFFIRM)

Used if pt symptomatic only or if symptomatic despite adequate rate control

Amiodarone (more effective but higher adverse effects)
Sotalol
Flecanide (contraindicated in structural heart disease or heart failure)
Cardioversion

Question 6

Exacerbators/contributors of AF

Answer 6

OSA
Obesity- legacy AF study: losing 10% body weight reduced recurrence
Alcohol
Thyroid dusfunction
Endurance exercise
Tobacco/illicit drugs

Question 7

Rhythm control : cardioversion

Answer 7

Indications

• Failure of rate control (persistent sumptoms or inadequate rate)
• First episode AF (generally young pts with normal LA, reversible underlying disorder)
• urgent if myocardial ischaemia, haemodynamic instability

Question 8

AF ablation

Answer 8

Significant sx
Mild atrial remodelling
Low-mod embolic risk
- maintenence of SR is aim: get pt to stop drinking, lose weight, tx OSA
- anticoagulate for 2-3 mths post then by RFs

Question 9

AV node ablation

Answer 9

Refractory symptomatic tachycardia
Ppm inserted- PPM dependent but no longer tachycardic
Remain in AF and still need anticoagulation

Question 10

How does Af impair myocardial fcn

Answer 10

1. Tachycardia related cardiomyopathy
2. Irregular rhythm
3. Loss of atrial kick for optimal ventricular filling
4. Activates neurohumoural vasoconstrictors such as angiotensin II and norepinephrine