Notwithstanding that the default should be stroke prevention for all AF patients unless deemed to be low risk, the focus should be to use scores to initially identify low risk patients who do not need antithrombotic therapy, rather than focus on identi cation of high risk patients. Prior guidelines have also opted for the CHA2DS2-VASc score to de ne a low risk group. The C in CHA2DS2-VASc refers to recent decompensated HF, irrespective of the ejection fraction (thus including HF with reduced ejection fraction or HF with preserved ejection fraction) or the presence of moderate-severe left ventricular systolic impairment on cardiac imaging, whether symptomatic or asymptomatic. The H refers to history of hypertension or uncontrolled BP, while S refers to stroke, systemic embolism, or a con rmed diagnosis of TIA. V refers to complicated vascular disease, including MI or PAD, or if performed, the presence of complex aortic plaque on TEE. Female sex (Sc criterion) is only relevant as a risk modi er if age > 65 or additional associated risk factors are present, given that females age < 65 with no other risk factors are not at excess stroke risk.66 Stroke risk is also dynamic, and risk should be re-assessed at every patient contact. This was seen in a study where the delta CHA2DS2VASc score, representing the change in stroke risk between between baseline and follow-up), was the best predictor for ischemic stroke.67 A stepwise approach to thromboprophylaxis would allow initial identi cation of low risk using CHA2DS2- VASc (Step 1), following which stroke prevention can be offered to all others (Step 2) irrespective of stroke point score or biomarkers used. This approach uses stroke risk scores in a reductionist manner to aid decision-making, and balances simplicity and practicality (and costs). Recommendations 1. 