Cardiovascular · Moderate
This case is fictional and exists for study. It describes no real patient.
68 years · female
A 68-year-old female presents to the emergency department with a 2-day history of lightheadedness, intermittent palpitations, and mild breathlessness on exertion. She has a past medical history of hypertension, which is well managed with amlodipine. She denies chest pain, orthopnoea, paroxysmal nocturnal dyspnoea, or syncope. On examination, her heart sounds reveal an irregularly irregular rhythm with variable pulse strength and a deficit between apical and radial pulse rates. Chest auscultation demonstrates clear breath sounds with no added crackles or wheeze. There is no peripheral oedema. An electrocardiogram is performed, showing absent P waves, irregular QRS complexes, and a ventricular rate of 135 beats per minute.
Vital signs
- HR
- 135 bpm
- BP
- 118/76 mmHg
- RR
- 18/min
- Temp
- 36.8 °C
- SpO₂
- 97%
Examination findings
- Irregularly irregular heart rhythm
- Apical-radial pulse deficit present
- Lungs clear to auscultation bilaterally
- No peripheral oedema
Investigations
| Sodium | 139 mmol/L | reference: 135-145 |
| Potassium | 4.2 mmol/L | reference: 3.5-5.0 |
| Serum Creatinine | 78 µmol/L | reference: 45-84 |
| eGFR | 72 mL/min/1.73m2 | reference: >60 |
| Haemoglobin | 13.2 g/dL | reference: 12.0-15.5 |
Question 1 of 3
Which of the following blood tests is most appropriate to perform next to investigate a potential reversible underlying cause for her atrial fibrillation?
Thyroid function tests (TFTs) should be routinely checked in newly diagnosed atrial fibrillation to rule out hyperthyroidism as a treatable trigger. Serum troponin is only indicated if acute coronary syndrome is clinically suspected. D-dimer is used in suspected pulmonary embolism/VTE, not routine AF evaluation. Digoxin levels are only measured in patients already receiving digoxin therapy.
Teaching point: Thyroid dysfunction, particularly hyperthyroidism, is a well-established reversible trigger for atrial fibrillation and should be screened for at presentation.
Question 2 of 3
The initial assessment confirms haemodynamically stable atrial fibrillation with rapid ventricular response. Which of the following is the most appropriate initial treatment for rate control?
First-line management for rate control in haemodynamically stable atrial fibrillation is a standard beta-blocker (such as bisoprolol) or a non-dihydropyridine calcium channel blocker (diltiazem or verapamil). Immediate DC cardioversion is reserved for patients with life-threatening haemodynamic instability (e.g., severe hypotension, acute pulmonary oedema, ongoing myocardial ischaemia). Intravenous amiodarone is not first-line for routine rate control in stable patients. Atropine is indicated for symptomatic bradycardia, not tachyarrhythmias.
Teaching point: Standard rate control strategy using a beta-blocker or rate-limiting calcium channel blocker is the first-line intervention for stable atrial fibrillation with rapid ventricular response.
Question 3 of 3
The patient's CHA2DS2-VASc score is calculated to assess her thromboembolic risk. Which of the following is the most appropriate long-term management strategy for stroke prevention?
The patient's CHA2DS2-VASc score is 3 (Age 65-74 = 1 point, Female sex = 1 point, History of Hypertension = 1 point). The patient's CHA2DS2-VASc score is 3 (age 65-74 = 1 point, female sex = 1 point, hypertension = 1 point). NICE (NG196) recommends offering anticoagulation with a direct oral anticoagulant to any person with atrial fibrillation and a CHA2DS2-VASc score of 2 or above, taking bleeding risk into account, and considering anticoagulation in men with a score of 1; stroke prevention is not offered to people under 65 years with no risk factors other than sex. Note that NICE applies no sex-specific threshold — the men 2 or above / women 3 or above rule belongs to the ESC, not to UK practice, and using it would wrongly withhold anticoagulation from a woman scoring 2. Bleeding risk should be assessed with the ORBIT score and modifiable risk factors addressed, but a high bleeding score is not in itself a reason to withhold anticoagulation. A DOAC (apixaban, rivaroxaban, edoxaban or dabigatran) is first-line unless contraindicated — in moderate-to-severe mitral stenosis or with a mechanical heart valve, warfarin is indicated. Aspirin monotherapy and dual antiplatelet therapy are no longer recommended for stroke prevention in atrial fibrillation, being less effective than anticoagulation with a comparable bleeding risk. A DOAC (e.g., apixaban, rivaroxaban, edoxaban, dabigatran) is first-line therapy unless contraindicated (e.g., moderate-to-severe mitral stenosis or mechanical heart valves, where warfarin is indicated). Antiplatelet monotherapy or dual antiplatelet therapy is no longer recommended for stroke prevention in atrial fibrillation due to reduced efficacy compared to anticoagulants and similar bleeding risks.
Teaching point: A direct oral anticoagulant (DOAC) is first-line long-term stroke prevention for non-valvular atrial fibrillation in patients with a qualifying CHA2DS2-VASc score.
Key learning points
- Haemodynamically stable fast atrial fibrillation should be initially managed with oral rate-control therapy (e.g., beta-blockers).
- Thyroid function tests should be routinely performed in new-onset atrial fibrillation to exclude hyperthyroidism.
- Long-term stroke risk should be evaluated using the CHA2DS2-VASc score, with DOACs serving as first-line anticoagulation for non-valvular AF.
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