Episode Seven: Atrial Fibrillation

Written by: Caleb Dusdal
Reviewed by: Kirstin Dawson


Objective One
In a patient who presents with new onset atrial fibrillation, look for an underlying cause

PIRATES

  • Pulmonary causes, thinking of Pulmonary embolism, or even Obstructive sleep apnea
  • Ischemia, or Infarct
  • Rheumatic heart disease or other valvular pathology
  • Alcohol,(sometimes called “holiday heart”) or Anaemia
  • Thyrotoxicosis, or Toxins
  • Electrolytes, or Endocarditis
  • Sepsis
  • Pericarditis
Objective Two
In a patient presenting with atrial fibrillation, look for haemodynamic instability, and intervene rapidly and appropriately to stabilize the patient.

Haemodynamic intability might look like:

  • altered mentation
  • hypotension, usually sBP <90mmHg in adults or a drop of 30% from their baseline
  • cardiac ischemia/angina
  • decompensated heart failure

If they are unstable, they need electrical cardioversion.

Objective Three
In an individual presenting with chronic or paroxysmal atrial fibrillation,
a.    Explore the need for anticoagulation based on the risk of stroke with the patient and
b.    Periodically reassess the need for anticoagulation.

ChadsVasc includes:

C – ongestive heart failure (+1 point)
H – ypertension (+1 point)
A -ge over 65(+1 point) or over 75(+2 points)
D – iabetes (+1 point)
S – troke, TIA or DVT/PE previously (+2 points)
Vasc history: prior MI, peripheral arterial disease (+1 point)

Can use Sparctool.com to compare stroke to bleed risk and compare effects of different anticoagulants

Canadian Cardiovascular Society Guidelines for anticoagulation:

For patients with Afib, continue to score them on a regular basis and assess their need for anticoagulation, the addition of an antiplatelet, or if they become higher risk of bleed.

Objective Four
In patients with atrial fibrillation, when the decision has been made to use anticoagulation, institute the appropriate therapy and patient education, with a comprehensive follow-up plan.

Institute the appropriate therapy:
per the above CCS guidelines. Generally this will be a DOAC these days, unless it is an valvular atrial fibrillation.

Educate the patient:
Describe to them the reason for the anticoagulation, the benefits and the risks. You can even share the results of the CHADS-65 and the Sparctool calculation so they can see exactly what went into your recommendations.

Objective Five
In a stable patient with atrial fibrillation, identify the need for rate control.

There has been no substantial evidence to suggest there are superior outcomes for one strategy versus the other(rate vs rhythm control), but there is evidence that rate control can reduce hospitalizations for all ages [Annals of Internal Medicine 2014 June 3, 2014 https://www.acpjournals.org/doi/10.7326/M13-1467 ] with mild atrial fibrillation symptoms.

There is emerging evidence that early (diagnosed less than 1 year ago) rhythm control may result in lower risk of adverse cardiovascular outcomes.

The Canadian Cardiovascular Society(CCS) recommends:

  1. The goals of ventricular rate control should be to improve symptoms and clinical outcomes, and that
  2. Treatment of persistent or permanent AF should target < 100 bpm
  3. The initial drug choice should be Beta-blockers, with CCB and Digoxin considered
    1. If heart failure, consider including Digoxin as an adjunct to the Beta-blocker
    1. If presence of CAD we can consider combination therapy with CCB if B-blocker monotherapy doesn’t cut it
    1. Otherwise, same preferences apply if no HF or CAD, and Digoxin is really only considered if they are particularly sedentary as it does not affect exertional heart rate like beta-blockers or non-DHP CCBs do.
Objective Six
In a stable patient with atrial fibrillation, arrange for rhythm correction when appropriate.

For a symptomatic but stable patient with atrial fibrillation, normally rate control should be the first approach to managing it.

However there are a few cases when rate control or cardioversion might be first line management:

  • If they are highly symptomatic: such as they are experiencing angina or similar symptoms
  • If they have previously been treated for this and have had many recurrences
  • If their Afib is persistent and is affecting their function
  • If the afib is causing cardiomyopathy
Sources Used

[From Tintinalli’s pp13] for the ECG features of Atrial Fibrillation

http://sparctool.com

CCS Atrial Fibrillation Guide 2018 update https://www.ccs.ca/images/Guidelines/PocketGuides_EN/AF_Gui_2018_PG_EN_web.pdf

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