NOAC PRN

Using Novel Oral Anticoagulants (NOAC) in case of prolonged atrial fibrillation

This guidance/explanation is to be used only in association with advice from a Cardiologist or Physician with experience in heart rhythm disorders.

For patients who experience paroxysmal or intermittent atrial fibrillation, it may be possible to suppress or inhibit attacks of atrial fibrillation using lifestyle measures and medication such as betablockers and/or Flecainide.

During periods of atrial fibrillation the left atrium ceases to empty normally and there is a risk of clots (thrombus) developing particularly in the area of the left atrial appendage. Occasionally this thrombus can detach and embolise into the atrial circulation causing trouble- eg strokes and heart attacks. See Blog

For this reason many patients who are prone to paroxysmal atrial fibrillation are offered long term anticoagulants to protect against this dreaded complication, but under certain circumstances there is an option for short term anticoagulation in the event of developing prolonged episodes of atrial fibrillation. The decision for this treatment should be made after consultation with a Physician prepared to offer this treatment and prescription.

The general principles are:

  1. No major risk factors such as prior TIA or Stroke related to Atrial Fibrillation
  2. Full understanding of principles, risks and benefits
  3. Paroxysmal atrial fibrillation
  4. Patient is fully aware of onset and termination of each attack so can define duration without difficulty (ie not for patients who have subclinical or those who have AF without being aware of it)
  5. The Patient is prepared to take responsibility for detection of Atrial fibrillation and self-medicate in event of prolonged episode.

If all of the above are true, because the small risk of bleeding while taking long term anticoagulants affects the ‘risk benefit’, it may be deemed safer for some patients to use anticoagulants intermittently during periods of higher risk.

Based on best available evidence and my experience, this  protocol can be used by selected patients to protect against stroke and embolism in event of developing atrial fibrillation that lasts greater than 24 hours (when the risk of blood clots rises substantially).

Principles of use

  • Left atrial thrombus is highly unusual in continuous periods of atrial fibrillation lasting less than 24 hours
  • Standard anticoagulants such as warfarin take 4-5 days to be effective and in the first 3 days can actually be pro-coagulant through inhibitory action on anticoagulant proteins C and S.
  • Novel Oral Anticoagulants (NOAC) such as Dabigatran and Rivaroxiban produce full anticoagulant effects within 6 hours of first dose.
  1. At onset of symptoms start clock and deploy anti-arrhythmic drug if using Pill in Pocket therapy.
  2. If AF lasts >24 hours take first dose of NOAC and continue prescription for at least 2 weeks or until seen by a Physician and return to normal heart Rhythm is confirmed.  
  3. In general the duration of taking anticoagulant needs to be extended until at least 1-3 weeks AFTER normal rhythm is restored.

A downloadable sheet is shown below.

 

Related stories and downloads

NOAC Local Guidelines for use




Written by

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Edward Leatham is a Consultant Cardiologist in Surrey and a Trustee of Haste and Haste Academy.

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