CCFP priority topic 8 of 105
Atrial Fibrillation on the CCFP exam
6 key features, the mistakes that cost marks, and a practice question.
Checked by a Canadian family physician, MD, CCFP. Updated October 20, 2026.
What the exam tests
Key features
The CFPC’s 6 key features for Atrial Fibrillation. Each one below has how the exam asks it, the common mistakes and the approach.
Practice question
Try one before you read
A real case from the bank, in the new short-menu format. Answer it first. Then read the key features.
Key feature 1 of 6
Find the cause
When atrial fibrillation (AF) is new, search for what set it off.
CFPC skill Clinical reasoningPhase Hypothesis generationSources Choosing Wisely Canada
On the exam
New AF found at a check-up in a tired, pale 70-year-old. Expect a short menu: you pick several tests from a list.
Pick the tests that find the cause.
Common mistakes
A Holter, carotid Doppler, CT for a lung clot or thyroid ultrasound with nothing pointing there. Each one needs a clue in the history first.
Approach
- Ask about chest pain, breathlessness, leg swelling, alcohol, stimulants, and heat intolerance or weight loss.
- Think of the heart: angina or a heart attack, heart failure, a weak heart muscle, valve disease.
- Then think beyond it: a clot in the lung, an overactive thyroid, heavy drinking.
- Order the tests that look for the causes above.
- Abnormal thyroid blood test (TSH)? No thyroid ultrasound unless you feel a lump.
Key feature 2 of 6
Stable or not
Check every patient in AF for failing circulation, and act fast if you find it.
CFPC skill Clinical reasoning, selectivityPhase Hypothesis generation, treatment
On the exam
A man on the ward, on apixaban, wakes in AF at 140/min with a fever. Expect a short menu: you pick the findings that matter.
Pick the findings that decide a shock.
Common mistakes
Calling him unstable for a rate of 140 alone. Or waiting on labs when the rhythm is truly causing collapse.
Approach
- Unstable means the rhythm is harming organs: low blood pressure with poor perfusion, ischemic chest pain, fluid on the lungs, or confusion.
- A fast rate alone is not instability. Judge what it does to the patient.
- If AF is causing the instability, it needs an urgent synchronized shock (electrical cardioversion).
- Look for a driver as well: sepsis, bleeding, low volume or a heart attack. A shock will not fix them.
- Stable? Treat the trigger first, send labs now, and slow the rate only if it stays fast.
Key feature 3 of 6
Stroke prevention
Weigh stroke against bleeding with the patient, and revisit the choice over time.
CFPC skill Patient-centred approach, clinical reasoningPhase Diagnosis, treatment, hypothesis generation, follow-upSources Thrombosis Canada
On the exam
An 81-year-old with AF takes naproxen for her knees. Expect a short menu: you pick the bleeding risks to change.
Pick the bleeding risks you can change.
Common mistakes
Holding the anticoagulant for her age or one drink a week. Age is the reason to treat. Fix what can change: the anti-inflammatory painkiller (NSAID), uncontrolled pressure.
Approach
- Score stroke risk with CHADS-65 (table below). Age 65 or more, or any CHADS2 factor, means an anticoagulant.
- A DOAC (direct oral anticoagulant: apixaban, dabigatran, edoxaban or rivaroxaban) is the preferred anticoagulant. Aspirin protects far less and still causes bleeding.
- For her, offer aspirin 81 mg daily only if she declines or cannot take an anticoagulant.
- Bleeding risk rarely rules out an anticoagulant. Those at high bleeding risk often gain the most.
- Fix what you can: blood pressure, NSAIDs, heavy alcohol, an antiplatelet she does not need, fall risk.
- Decide with her: her stroke risk, her bleeding risk, and what she wants.
- Look again at each review, every 6 to 12 months. A 65th birthday or a new diagnosis can change the answer.
| Patient | Give | Note |
|---|---|---|
| Age 65 or older | Anticoagulant, a DOAC by choice | Age alone is enough |
| Under 65 with heart failure, high blood pressure, diabetes, or past stroke or mini-stroke (TIA) | Anticoagulant, a DOAC by choice | Any one factor is enough |
| Under 65, none of these, with coronary or other artery disease | Aspirin 81 mg daily | Not an anticoagulant |
| Under 65 with none of the above | Nothing | No antithrombotic needed |
Key feature 4 of 6
Starting a DOAC
Once an anticoagulant is chosen, start it right, teach it, and plan the follow-up.
CFPC skill Clinical reasoningPhase Treatment, follow-upSources Thrombosis Canada
On the exam
An 84-year-old woman, 58 kg, creatinine 95 µmol/L, starts apixaban. Expect one best answer for the dose, then a short menu for follow-up.
Pick the dose, then the follow-up tests.
Common mistakes
Full-dose apixaban because her creatinine is under 133: age and weight already make two criteria. Or a blood clotting test (INR) or drug level to check the dose.
Approach
- Pick a DOAC over warfarin. Use warfarin, INR 2 to 3, for a mechanical valve, severe mitral stenosis or rheumatic valve disease.
- Estimate creatinine clearance with the Cockcroft-Gault formula before you start. Dose from the table below.
- Teach: never double a missed dose; take the next one on time. Avoid regular anti-inflammatory painkillers (NSAIDs): use acetaminophen for joint pain. Avoid St. John's wort.
- Teach: alcohol in moderation is fine, and there are no food rules. Rivaroxaban is taken with a meal.
- See her every 6 to 12 months: bleeding, adherence, new drugs, blood count and creatinine. Confirm she still needs it.
- Recheck clearance yearly at 50 mL/min or more. Below 50, every 6 months, or every 3 on rivaroxaban below 30. Apixaban below 30: ask a specialist. Recheck with any acute illness.
- Don't monitor with INR or drug levels. The INR does not measure a DOAC, and no target level exists.
| DOAC | Usual dose | Lower dose or avoid |
|---|---|---|
| Apixaban | 5 mg twice daily | 2.5 mg twice daily with 2 of: age 80 or more, weight 60 kg or less, creatinine 133 µmol/L or more. Clearance 15 to 30: no dose advice. Under 15: avoid. |
| Rivaroxaban | 20 mg daily, with food | 15 mg daily at clearance 15 to 49, with caution below 30. Under 15: avoid. |
| Dabigatran | 150 mg twice daily | 110 mg twice daily at 80 or older; consider it over 75 with bleeding risk. Clearance under 30: avoid. |
| Edoxaban | 60 mg daily | 30 mg daily at clearance 15 to 50, weight under 60 kg, or with certain interacting drugs. Under 15: avoid. |
Key feature 5 of 6
Rate control
When the patient is stable, decide if the rate needs slowing, and how.
CFPC skill Clinical reasoningPhase Hypothesis generation, treatment
On the exam
Known AF, rate 130 on the ward after a held beta-blocker and a fever. Expect one best answer from a list.
Pick the best next step for the rate.
Common mistakes
A shock in a stable patient. Or adding diltiazem while the patient's own beta-blocker sits unused. Restart it and treat the fever.
Approach
- Look for what pushed the rate up: fever, infection, pain, bleeding, low volume, a missed rate drug, alcohol withdrawal, the thyroid.
- Treat that trigger first. A shock does not fix sepsis or a missed dose.
- Restart a held rate drug before you add a new one. Two drugs that slow the heart's conduction need a reason.
- Then choose a rate drug that suits the patient's heart and other illnesses.
Key feature 6 of 6
Rhythm control
When the patient is stable, know when to restore normal rhythm, and arrange it.
CFPC skill Clinical reasoning, selectivityPhase Hypothesis generation, treatment
On the exam
A fit 78-year-old man on apixaban for months, in AF for weeks, rate 74, breathless on the ward. Expect one best answer from a list.
Pick the best plan for his rhythm.
Common mistakes
Adding a rate drug when his rate is already 74. His problem is the lost rhythm, not the rate.
Approach
- Ask what the rhythm has cost him: breathlessness, tiredness, lost exercise. Symptoms with a controlled rate point to rhythm control.
- Think of it too when AF is recent or worsens heart failure, and when the patient prefers it.
- Before a planned shock, check that his anticoagulant has run without a break.
- Refer for a shock to reset the rhythm, rhythm drugs, or ablation (a catheter procedure that stops the misfiring).
Flashcards
Answer it first, then check.
KF 1New AF and a low TSH, with no lump in the neck. Thyroid ultrasound?
No. A thyroid ultrasound is not routine for abnormal thyroid tests without a palpable lump. Source: Choosing Wisely Canada
KF 2AF at 140/min, blood pressure 124/80, warm and alert. Is he unstable?
No. Instability means low pressure, ischemia, fluid on the lungs or confusion. Rate alone does not count.
KF 3A 66-year-old has AF and no other illness. Does she need an anticoagulant?
Yes. Age 65 or older is enough on its own. A DOAC is the preferred choice. Source: Thrombosis Canada
KF 3A 58-year-old has AF and coronary disease, nothing else. What stroke prevention?
Aspirin 81 mg daily. Under 65 with no CHADS2 factor, artery disease calls for aspirin. Source: Thrombosis Canada
KF 4She is 84, weighs 58 kg, creatinine 95 µmol/L. What apixaban dose?
2.5 mg twice daily. Age 80 or more and weight 60 kg or less make two criteria. Source: Thrombosis Canada
KF 4She takes apixaban and her INR is 1.1. Is she protected?
You cannot tell. The INR does not measure a DOAC, so a normal result proves nothing. Source: Thrombosis Canada
KF 4Her creatinine clearance is 40 mL/min on apixaban. How often do you recheck it?
Every 6 months, and with any acute illness. At 50 mL/min or more, once a year. Source: Thrombosis Canada
KF 5Known AF, rate 130 after a held beta-blocker and a fever. First step?
Restart his beta-blocker and treat the fever. Don't add a new rate drug or shock him.
FAQ
Which stroke score does the exam expect?
CHADS-65, the one Canadian advice is built on. Age 65 or more, or any CHADS2 factor, means an anticoagulant. CHA2DS2-VASc adds points for age 65 to 74, 2 points for 75 or more, female sex and artery disease.
Is warfarin ever still the right choice?
Yes, with a mechanical heart valve, severe mitral stenosis or rheumatic valve disease, where DOACs are not used. Warfarin then targets an INR of 2 to 3. Otherwise a DOAC is preferred.
Does a high bleeding score mean no anticoagulant?
Rarely. People at high bleeding risk often gain the most from stroke prevention. Use the score to find what you can fix: blood pressure, NSAIDs, alcohol, extra antiplatelets.
Do DOAC doses use creatinine or creatinine clearance?
Mostly clearance, estimated with the Cockcroft-Gault formula. Apixaban is the exception: its lower dose uses age, weight, and a creatinine of 133 µmol/L or more.
Sources
Written from the CFPC Assessment Objectives and Canadian guidelines first. Checked by a Canadian family physician, MD, CCFP.
Last reviewed October 20, 2026For exam study. Not advice for a patient in front of you.
- Assessment Objectives for Certification in Family Medicine, 2nd editionCollege of Family Physicians of Canada · 2020
- Choosing Wisely recommendationsChoosing Wisely Canada
- Clinical guidesThrombosis Canada