See the MHRA advice on warfarin and other anticoagulants monitoring of patients during the COVID-19 pandemic, which includes reports of supratherapeutic anticoagulation with warfarin. Who is it for? Healthcare professionals Commissioners and providers People with atrial fibrillation, their families and carers Recommendations People have the right to be involved in discussions and make informed decisions about their care, as described in NICE's information on making decisions about your care. Making decisions using NICE guidelines explains how we use words to show the strength (or certainty) of our recommendations, and has information about prescribing medicines (including off-label use), professional guidelines, standards and laws (including on consent and mental capacity), and safeguarding. 1.1 Detection and diagnosis 1.1.1 Perform manual pulse palpation to assess for the presence of an irregular pulse if there is a suspicion of atrial fibrillation. This includes people presenting with any of the following: breathlessness palpitations syncope or dizziness chest discomfort stroke or transient ischaemic attack. [2006] 1.1.2 Perform a 12-lead electrocardiogram (ECG) to make a diagnosis of atrial fibrillation if an irregular pulse is detected in people with suspected atrial fibrillation with or without symptoms. [2021] 1.1.3 In people with suspected paroxysmal atrial fibrillation undetected by 12-lead ECG recording: use a 24-hour ambulatory ECG monitor if asymptomatic episodes are suspected or symptomatic episodes are less than 24 hours apart use an ambulatory ECG monitor, event recorder or other ECG technology for a period appropriate to detect atrial fibrillation if symptomatic episodes are more than 24 hours apart. [2021] For a short explanation of why the committee made the 2021 recommendations and how they might affect practice, see the rationale and impact section on detection and diagnosis. 