(Med) Cvs - Atrial Fibrillation

Front 1

What are the 3 types of AF?

Back 1

1) Paroxysmal (acute AF)
- flipping in and out spontaneously without cardioversion

2) Persistent (acute AF)
- lasting days or weeks, won't spontaneously revert

3) Permanent (chronic AF)
- always in AF, unsuccessful cardioversions

Front 2

What are the main causes of AF?

Back 2

1) Cardiac diseases
- HF, HTN, MI, mitral valve disease, CMP...

2) Non-cardiac diseases
- PE, pneumonia, hyperthyroidism...

3) Other
- caffeine, alcohol, post-op

Front 3

What investigations do you do for AF?

Back 3

1) ECG (absent P-waves, irregular QRS complexes)

2) Bloods – U&E (with Mg2+ & K+), Cardiac Trops, TFTs

3) Consider Echo

Front 4

Outline the management principles of treating AF

Back 4

Control Rate:
1. b-blockers (Metoprolol, atenolol)
2. calcium channel blockers (Verapamil, diltiazem)
3. Digoxin (old drug – useful in heart failure or C/I to above two drugs)

Control Rhythm:
• DC Cardioversion
• Pharmacological: Amiodarone, Flecainide, Sotalol

Anticoagulate:
• Short term – LMWH
• Long term – CHADS2 (0 = Aspirin, 1 = Aspirin or Warfarin, ≥2 = Warfarin)

Front 5

What is the management of acute AF?

Back 5

In acute AF: immediate cardioversion is the priority (either electrical or chemical)

- DRABCD
1) Cardioversion
2) Control rate
3) Anticoagulate

Front 6

How do you cardiovert someone in acute AF?

Back 6

• Electrical (DC) – 100J in an adult, 200-300J if large

• Pharmacological (IV or oral): Amiodarone (IV or oral) OR Flecainide (IV or oral)
__________

• After cardioversion: may need (risks/benefits) oral antiarrythmics to maintain sinus rhythm
1. Flecanide (oral)
1. Sotalol (oral)
2. Amiodarone (oral)

Front 7

When do you not cardiovert someone who presents in acute AF?

Back 7

• there is a risk of thromboembolus cased by converting arrhythmia back to sinus – ‘atrial stunning’ (transient dysfunction of the atrium and atrial appendage)
 Immediate cardioversion:
i. If haemodynamically unstable (benefit>risk)
ii. If onset <48 hours (left atrial thrombus hasn’t had time to form yet)
iii. If onset >48 hours (or onset time unknown) AND no thrombus on TOE (not TTE)
 3 weeks of anticoagulation (usually warfarin) then cardioversion:
i. If onset >48 hours (or onset time unknown) AND visible thrombus on TOE
ii. If onset >48 hours (or onset time unknown) AND TOE unavailable (eg. Albany)

Front 8

How do you anticoagulate someone before cardioversion?

Back 8

• If immediate cardioversion -> heparin/LMWH just before procedure (then ≥4 weeks after)
• If not immediate -> 3 weeks of warfarin/dabigatran (then ≥4 weeks after)

Front 9

How do you anticoagulate someone after cardioversion?

Back 9

Anticoagulation after cardioversion
No current consensus, based on the patient; the decision may be made to anticoagulate anywhere from 1 month post-cardioversion to lifelong anticoagulation. Examples:
o After DC cardioversion – must anticoagulate for at least 1 month -> due to atrial stunning
o Usually wise to continue warfarin/dabigatran for at least 6-12 months post-cardioversion
o If cardioverted successfully with Amiodarone after a brief episode of acute AF for the first time -> will most likely not need anticoagulation for life (assess cardiovascular risk factors of course)
o If cardioverted successfully with Amiodarone after longstanding AF -> probably need it for life

• Short-term (in hospital):
1. LMWH: Dalteparin (SC) OR Enoxaparin (SC)
1. Unfractionated Heparin (IV)
• Long-term:
1. Warfarin (oral)
1. Dabigatran (oral)