Atrial Fibrillation

Question 1

AF Overview

Answer 1

• 2-4% of population in developed nation
• AF-related stroke accounts for 25% of Ischaemic stroke in Australia

Basis of stroke prevention in AF
1 Assess stroke risk using CHA2DS2VA score
2 Assess and correct reversible bleeding factors
3 Shared decision making with patient to determine anticoagulation prescription.
4 Monitor therapy regularly

Question 2

CHA2DS2-VA Score

Answer 2

C - Congestive heart failure
H - Hypertension history
A2 - Age > 75
D - Diabetes
S2 - Previous Stroke or TIA
V - Vascular Disease
A - Age 65-74yo

Sex criteria is not used in stroke risk prediction in Australia.

> = 2 - OAC recommended.

Question 3

Reversible bleeding factors to correct in AF patients

Answer 3

• Hypertension
• Frailty and falls
• Labile INR
• Impaired renal or hepatic function
• Anaemia
• Peptic Ulceration
• Excess alcohol (>8std per week)
• Anti-platelet agents and NSAIDS.

Question 4

Shared decision making with patients to determine anticoagulation prescription

Answer 4

• Non-valvular AF - NOAC (Non vitamin K oral anti-coagulation) recommended as 1st line.
  
  • As good or better than warfarin in preventing stroke risk
  • Lower risk of intracranial haemorrhage
  • Easier for patients and physicians to use.
• Anti-platelet therapy not recommended for stroke prevention regardless of stroke risk.
  
  • If DAPT needed post ACS, continue triple therapy (NOAC, Aspirin, Clopidogrel) until 12 months after ACS or stent-implantation.

Question 5

Medication Decision Making in AF

Answer 5

Haemodynamic and new (<48 hours)? - DC cardioversion
- Old and needing cardioversion? TOE to review for LA thrombus. if not present, can cardiovert.
Thrombus present? Need 3 weeks anticoagulation prior to cardioversion attempt.

LV dysfunction or clinical signs of heart failure?
- Yes - Amiodarone
- No - betablocker or non-DHP Ca Blocker

Suboptimal control of above?
- Add Digoxin.

Question 6

Classification of AF

Answer 6

• First diagnosis - No previous documentation
• Paroxysmal - Episodes are self-limiting within 48 hours, but episodes can last up to 7 days.
• Persistent - > 7 days.
• Long-standing persistent - > 1 year
• Permanent - Rhythm control is no longer used because AF is accepted by patient.

Question 7

Rate-control for AF

Answer 7

Aim : Resting HR <= 110bpm

• Medications
• Beta blockers
  
  • Atenolol 25mg PO OD
  • Metoprolol Tartrate 25mg PO BD
  • LV Dysfunction present? Choose one of Carvedilol, Bisoprolol, Nebivolol, Metoprolol Succinate
• Non-DHP Ca Channel blocker
  
  • Use if beta blocker contraindicated or not tolerated and no LV dysfunction (negative inotropic effect)
    
    • Diltiazem MR 180mg PO OD
    • Verapamil 180mg PO OD

LVDysfunction?
- Can Consider Amiodarone 200mg PO OD.

Question 8

Rhythm Control of AF

Answer 8

Aim: Restore sinus rhythm

DC Cardioversion
Haemodynamic and new (<48 hours)? - DC cardioversion
- Old and needing cardioversion? TOE to review for LA thrombus. if not present, can cardiovert.
Thrombus present? Need 3 weeks anticoagulation prior to cardioversion attempt.

Chemical Cardioversion
- Normal LV function? Flecainide IVIF preferred
- LV dysfunction or coronary disease - Amiodarone IVIF preferred

Question 9

CHA2DS2-VaSc

Answer 9

Clinical risk factors for stroke, TIA and systemic embolism in presence of AF

CHF
HTN
Age >= 75 + 2
Diabetes Mellitus
Stroke/TIA/VTE + 2
Vascular (PAD,Prior MI)
Sex - F

Male >= 2 and Female >= 3 - Strong evidence showing oral anticoagulation is indicated.

Question 10

Valvular AF

Answer 10

AF with moderate or severe Mitral stenosis or mechanical heart valve.
- Increased risk of VTE and stroke compared to non-valvular AF.
- Anticoagulate with Warfarin irrespective of other risk factors.

Question 11

Perioperative management of NOAC

Answer 11

3:2 2:1 rule

High bleeding risk? Withold 3 days prior and 2 days post operation.
Low bleeding risk? Withhold 2 days prior and 1 day post operation

Question 12

Low bleeding risk operations

Answer 12

• Hernia repair
• Abdominal hysterectomy
• Arthroscopic surgery lasting < 45mins
• Axillary node dissection
• Bronchoscopy +/- biopsy
• Carpal tunnel repair
• Cataract and non-cataract eye surgery
• CVS catheter removal
• Cholecystectomy
• D & C
• Gastrointestinal endoscopy / colonoscopy
• ERCP
• Haemorrhoidal surgery
• Hydrocoele repair
• Pacemaker insertion
• Tooth extractions
• Thoracentesis.

Question 13

Perioperative management of anti-platelets

Answer 13

Withold 7-10 days prior to operation and resume on recommencement of oral intake.