Atrial fibrillation — structured written assessment

SAQ 1 (10 marks)

Practice scenario. A 74-year-old woman with treated hypertension and type 2 diabetes presents with 2 days of palpitations. She is alert, with BP 136/82 mmHg and no chest pain or breathlessness. A 12-lead ECG shows AF at 125 b.p.m. without pre-excitation, and she has no asthma or bronchospasm. She has no heart failure, no previous stroke, TIA or thromboembolism, and no coronary, peripheral arterial or aortic disease. Her echocardiogram shows LVEF 60%. She weighs 70 kg, her serum creatinine is 90 µmol/L, and she has no mechanical valve or mitral stenosis and no history of bleeding.^[1]

1. Give the 2024 ESC definition of AF and its ECG requirement for diagnosis. (2)^[1]
2. Calculate her CHA2DS2-VA score and state the ESC 2024 recommendation on oral anticoagulation; give her CHA2DS2-VASc score and the ACC/AHA 2023 recommendation. (4)^[1][2]
3. Choose an anticoagulant and dose under ESC 2024, with the reason. (2)^[1]
4. Choose first-line rate control under ESC 2024. (2)^[1]

Model answers

• Q1. AF is a supraventricular arrhythmia with uncoordinated atrial activation and loss of effective atrial contraction; the ECG shows no discernible, regular P waves and irregular ventricular activation, with no specific RR pattern in the absence of atrioventricular block. Confirmation by an ECG (12-lead, multiple or single leads) is recommended to establish the diagnosis of clinical AF and commence risk stratification and treatment (ESC 2024, Class I, level A).^[1]
• Q2 (ESC). CHA2DS2-VA = 3: hypertension 1, diabetes 1, age 65–74 years 1; there is no sex criterion. A score of 2 or more is recommended as an indicator of elevated thromboembolic risk for decisions on initiating OAC (Class I, level C), and OAC is recommended in clinical AF at elevated thromboembolic risk to prevent ischaemic stroke and thromboembolism (Class I, level A).^[1]
• Q2 (ACC/AHA). CHA2DS2-VASc = 4, adding 1 for female sex. For an estimated annual thromboembolic risk of 2% or more (e.g. CHA2DS2-VASc 2 or more in men and 3 or more in women), anticoagulation is recommended to prevent stroke and systemic thromboembolism (COR 1, LOE A).^[1][2]
• Q3. DOACs are recommended in preference to VKAs to prevent ischaemic stroke and thromboembolism, except in patients with mechanical heart valves or moderate-to-severe mitral stenosis (ESC 2024, Class I, level A); she has neither, so a DOAC is chosen. For example, apixaban 5 mg twice daily: she meets none of the three apixaban dose-reduction criteria (age 80 years or more, body weight 60 kg or less, serum creatinine 133 µmol/L or more), and a reduced dose is not recommended unless DOAC-specific criteria (Table 11) are met, to prevent underdosing and avoidable thromboembolic events (Class III, level B).^[1]
• Q4. With LVEF above 40%, beta-blockers, diltiazem, verapamil or digoxin are recommended as first-choice drugs to control heart rate and reduce symptoms (ESC 2024, Class I, level B); lenient rate control with a resting heart rate under 110 b.p.m. should be considered as the initial target, with stricter control reserved for those with continuing AF-related symptoms (Class IIa, level B).^[1]

SAQ 2 (10 marks)

Practice scenario. A 69-year-old man with AF on rivaroxaban 20 mg once daily (CHA2DS2-VA score 3; creatinine clearance 70 mL/min) has a non-ST-elevation acute coronary syndrome and an uncomplicated PCI with a drug-eluting stent. He does not have diabetes. His thrombotic risk is judged low.^[1]

1. Outline his ESC 2024 antithrombotic plan after PCI, with class and level. (4)^[1]
2. When would ESC 2024 consider longer triple therapy, and for how long? (2)^[1]
3. When should a lower rivaroxaban dose be considered with antiplatelet therapy? (2)^[1]
4. Give the corresponding ACC/AHA 2023 rows. (2)^[2]

Model answers

• Q1. In the ESC text, peri-procedural triple therapy (OAC, aspirin and a P2Y12 inhibitor) should be the default strategy for most patients, then early cessation (1 week or less) of aspirin and continuation of an oral anticoagulant (preferably DOAC) with a P2Y12 inhibitor (preferably clopidogrel) for up to 12 months is recommended in AF patients with ACS undergoing an uncomplicated PCI, to avoid major bleeding, if the risk of thrombosis is low or bleeding risk is high (Class I, level A). In patients with AF and an indication for concomitant antiplatelet therapy, a DOAC is recommended in eligible patients in preference to a VKA to mitigate bleeding risk and prevent thromboembolism (Class I, level A). After 12 months, antiplatelet therapy is not recommended in stable patients with chronic coronary or vascular disease treated with OAC, due to lack of efficacy and to avoid major bleeding (Class III, level B).^[1]
• Q2. Triple therapy with aspirin, clopidogrel and OAC for longer than 1 week after an ACS should be considered in patients with AF when ischaemic risk outweighs bleeding risk, with the total duration (1 month or less) decided according to assessment of these risks and clear documentation of the discharge treatment plan (Class IIa, level C). In AF patients with ACS or chronic coronary syndrome and diabetes undergoing coronary stent implantation, the ESC text adds that prolonging triple therapy with low-dose aspirin, clopidogrel and an OAC up to 3 months may be of benefit if thrombotic risk outweighs bleeding risk in the individual patient; he does not have diabetes.^[1]
• Q3. Rivaroxaban 15 mg once daily should be considered in preference to 20 mg once daily when combined with antiplatelet therapy in patients where concerns about bleeding risk prevail over concerns about stent thrombosis or ischaemic stroke (ESC 2024, Class IIa, level B).^[1]
• Q4. ACC/AHA 2023: in AF with increased stroke risk undergoing PCI, DOACs are preferred over VKAs in combination with antiplatelet therapy to reduce clinically relevant bleeding (COR 1, LOE A); in most patients with AF on OAC undergoing PCI, early discontinuation of aspirin (1–4 weeks) with continued OAC and a P2Y12 inhibitor is preferred over triple therapy to reduce the risk of clinically relevant bleeding (COR 1, LOE A).^[2]