Atrial Fibrillation

In this chapter, you will find Canadian guidelines for management of atrial fibrillation. We have also provided you with links to relevant scoring tools to determine if stroke prevention therapy should be recommended for patients (CHA₂DS₂-VASc & HAS-BLED).

Student Resources

Atrial Fibrillation One Pager

Arrhythmias Drug Table

Tools

HAS-BLED
Purpose Assess risk of bleed in patients with atrial fibrillation on anticoagulant therapy (for stroke prevention).
Type of Resource Scoring tool
Included Tool consists of risk factors associated with increased bleeding risk.
Score ranges from 0-9 to classify patients into low to high bleed risk:

  • 0-1=low risk
  • 2= moderate risk
  • 3+ = high risk

Provides interpretation of results and recommendation on whether to start anticoagulation therapy.
Student Bottom Line When a patient is diagnosed with atrial fibrillation, use this scoring tool to determine if anticoagulation therapy is safe to initiate (based on bleeding risk). Use your clinical judgement to assess stroke risk and bleed risk.
VIEW RESOURCE
CHADS2
Purpose Assess 1 year risk of stroke in patients with atrial fibrillation to guide need for anticoagulation therapy (similar to CHA₂DS₂-VASc).
Type of Resource Scoring tool
Included Tool consists of risk factors associated with increased stroke risk. Score ranges from 0-6 to classify patient into low to high risk of thromboembolic event:

  • 0=low risk
  • 1-2 = intermediate risk
  • 3=high risk
Student Bottom Line When a patient is diagnosed with atrial fibrillation, use this scoring tool to determine if stroke prevention therapy is necessary.

*Important to compare to bleeding risk*
VIEW RESOURCE
CHA₂DS₂-VASc
Purpose Assess 1 year risk of stroke in patients with atrial fibrillation to guide need for anticoagulation therapy (similar to CHADS₂).
Type of Resource Scoring
Included Tool consists of risk factors associated with increased stroke risk.
Score ranges from 0-9 to classify patient into low to high risk of thromboembolic event:

  • For males: score 0=low risk, 1=low-moderate risk & 2+ is moderate to high risk
  • For females: score 1=low risk, 2=low-moderate risk & 3+ is moderate to high risk

Provides recommendation on whether to start anticoagulation therapy.
Student Bottom Line When a patient is diagnosed with atrial fibrillation, use this scoring tool to determine if stroke prevention therapy is necessary.

*Important to compare to bleeding risk

Although there is no statistical difference between CHA₂DS₂-VASc and CHADS₂ , CHA₂DS₂-VASc is preferred.

  • Why? Incorportates more risk factors (ex. Different age ranges, sex)

If a patient is considered “low risk”, CHA₂DS₂-VASc can better assess the need for anticoagulation (ex. Patient may have a score of 0 with CHADS₂ but CHA₂DS₂-VASc may be different).
VIEW RESOURCE
SPARCtool
Purpose Assess both the risk and benefits of starting anticoagulation therapy in patients with atrial fibrillation.
Type of Resource Scoring tool
Included Combination of both CHA₂DS₂-VASc (stroke risk) and HAS-BLED (bleeding risk).

  • Updated regularly (last update May 2023)
  • Provides absolute and relative risk reduction with specific drug therapies
  • Information presented in both table and bar graph form
Student Bottom Line If you are interested in calculating both stroke and bleed risk in AF patients, this quick and easy tool will not only calculate the scores but will also assess the benefit and risk of specific drug therapies and overall benefit.

If you are interested in the interpretation of CHA₂DS₂-VASc and HAS-BLED scores, it is best to use their individual scoring tools.
VIEW RESOURCE
Tisdale Risk Score for QT prolongation
Purpose Predicts risk of QT prolongation.
Type of Resource Scoring Tool
Included Includes risk factors and provides a risk score based on the information inputted.
Student Bottom Line Risk of QT prolongation is an important consideration in AF. Many medications can cause QT prolongation so this scoring tool is handy to use to assess the severity of the risk.
VIEW RESOURCE

Guidelines

The Canadian Cardiovascular Society Guidelines
Purpose Guide treatment recommendations for patients diagnosed with atrial fibrillation. Includes treatment for both acute symptoms and long term rate and rhythm control.
Type of Resource Canadian Guidelines (updated frequently – last update 2020)
Included
  • Clinical investigations of condition (risk factors, classification, signs and symptoms)
  • Rate and rhythm management algorithms (acute and chronic)
  • Stroke prevention treatment
  • Dosing
    • Renal adjustments
    • Special populations
      • Ex. Apixaban 2.5mg BID if 2+ criteria
        • 80+ years old
        • 60kg of less
        • SCr 133umol/L +
  • Special considerations based on co-morbidities (ex. AF + CAD)
Student Bottom Line The recommended resource to guide treatment for patients diagnosed with atrial fibrillation. The flowcharts and algorithms in the pocket guide are a great tool for studying and practicum purposes. For more details and information, the full guidelines are preferred.
VIEW RESOURCE (full guidelines) – VIEW RESOURCE (pocket guidelines)
Credible Meds
Purpose Provides QT drug risk.
Type of Resource Informative resource (requires making an account)
Included Type in medication to assess the QT risk.
Student Bottom Line We recommend using the information on this website in addition to the Tisdale risk score tool to assess QT prolongation risk.
VIEW RESOURCE
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Rxpid Resources Copyright © 2023 by Olivia Bailey is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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