Atrial Fibrillation (AF)

Question 1

Presentation of AF

Answer 1

• Palpitations
• SOB
• Syncope
• Symptoms of associated conditions (i.e. stroke, sepsis, thyrotoxicosis)

Question 2

Causes of AF (remember SMITH)

Answer 2

• Sepsis
• Mitral valve pathology
• Ischaemic heart disease
• Thyrotoxicosis
• Hypertension

Question 3

Pathophysiology of AF

Answer 3

• Usually associated with anatomically and histologically abnormal atria because of underlying heart disease.
• Dilation of the atria with fibrosis and inflammation causes a difference in refractory periods within the atrial tissue and promotes electrical re-entry that results in AF.
• The fractionation of a mother wave into multiple wavelets in the presence of enlarged atria, in conjunction with the short refractory periods and slow conduction properties of the atria, lead to sustained AF.

Question 4

ECG Findings

Answer 4

• Absent P waves
• Narrow QRS complex tachycardia
• Irregularly irregular ventricular rhythm

Question 5

Treatment of AF

Answer 5

• Rate control first line unless:
  
  • Reversible cause
  • New onset (<48hrs)
  • AF causing HF
  • Remain symptomatic despite rate control
• Rate control
  
  • Beta-blocker (i.e. atenolol)
  • Calcium-channel blocker (diltiazem)
  • Digoxin (only in sedentary people, needs monitoring)
• Rhythm control (delay if onset >48hrs ago and stable) if:
  
  • Synchronised ​DC cardioversion
  • Pharmacological cardioversion
    
    • Flecanide (no structural heart disease)
    • Amiodarone (with structural heart disease)
• CHA₂DS₂-VASc risk scores
  
  • Patients likely to benefit from OAC – score of ≥ 1 for men and ≥ 2 for women
  • Medical therapy
    
    • Warfarin or DOAC (i.e. apixaban)

Question 6

Complications of AF

Answer 6

• Death
• Bradycardia
• Thromboembolism/stroke
• Hypotension
• Heart failure
• Arrhythmia associated with anti-arrhythmic drugs
• Amiodarone-associated thyroid dysfunction
• Exacerbation of reactive airways disease from BB
• Complications of surgical ablation
• Amiodarone-associated pulmonary toxicity
• Complications of catheter ablation

Question 7

Prevention of AF

Answer 7

• Primary prevention
  
  • ACE-I, statins and specific dietary lipid components
  • Preoperative BB or amiodarone reduce postoperative incidence
• Secondary prevention
  
  • Weight reduction

Question 8

CHA2DS2-VASc

Answer 8