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Atrial Fibrillation

From Mediwikis

This is the most common cardiac arrhythmia, and can be asymptomatic; it can be detected by taking the patient's pulse and noting its irregularly irregular rhythm.

  • Acute: onset within the previous 48 hours (if less than 48 hours, won't increase risk of stroke during electrical cardioversion)
  • New onset: AF identified for first time eg on ECG
  • Paroxysmal: spontaneous termination within seven days and most often within 48 hours.
  • Persistent: not self-terminating; lasting longer than seven days, or prior cardioversion.
  • Permanent: Long-standing AF (> 1 year) that is not successfully terminated by cardioversion, when cardioversion is not pursued or has relapsed following termination.

Causes

  • Hyperthyroidism
  • High Alcohol Intake
  • High Caffeine Intake
  • Heart disease (eg: rheumatic heart disease, ischaemic heart disease, WPW)
  • Dehydration - electrolyte changes
  • Acute infections
  • Hypertension

Signs & Symptoms

  • Palpitations
  • Exercise Intolerance
  • Shortness of Breath
  • Irregularly Irregular pulse

Investigations

ECG changes:

  • Irregularly irregular R-R intervals
  • Chaotic P wave activity (often can't see P waves)
  • Normal QRS complexes

Chest X-Ray & Echocardiography may also be performed to exclude other causes

Management

  • New-onset AF = cardioversion - electrically if unstable CV status or >48 hours; pharmacological if stable
  • Paroxysmal AF= Rhythm control - beta blocker or other rhythm control drugs; pill in the pocket
  • Persistent AF= Rate or Rhythm control (if reversible cause or heart failure caused by AF)
  • Permanent AF= Rate control

Rhythm Control

  • Medical cardioversion- flecanide, propafenone, amiodarone
  • AV node ablation
  • Pacemaker

Rate Control

  • β-blocker (atenolol, metoprolol) or rate limiting calcium channel blocker (diltiazem, verapamil)
  • If this fails, use digoxin if sedentary

Always consider anticoagulation!! - Warfarin or NOACs to prevent stroke.

CHADSVASc Score - Congestive heart failure, hypertension, age (65-74 – 1; >=75 – 2), DM, Stroke/TIA/thromboembolism (2); vascular disease, female - Offer anticoagulation if score >=2; or >=1in men

Asses risk of bleeding using HAS-BLED: Hypertension (>160mmHg uncontrolled), Abnormal renal function; liver function; Stroke, prior major Bleeding/predisposition to bleeding, Labile INR, Elderly (age>=65), Drug therapy - medication (antiplatelet agents, NSAIDS), alcohol history (>=8drinks/week)

Potential screening for atrial fibrillation in the future to pick up people earlier and prophylactically manage with anticoagulation.[1]

References

  1. oran PS, Teljeur C, Ryan M, Smith SM. Systematic screening for the detection of atrial fibrillation. Cochrane Database of Systematic Reviews 2016, Issue 6. Art. No.: CD009586. DOI: 10.1002/14651858.CD009586.pub3.