What are the recommended investigations for a patient with new-onset atrial fibrillation?

For a patient presenting with new-onset atrial fibrillation (AF), the recommended investigations include several key steps to diagnose the condition, assess risks, and identify underlying causes ².

Initial Diagnosis:

• Initially, perform manual pulse palpation to check for an irregular pulse if AF is suspected ².
• If an irregular pulse is detected, a 12-lead electrocardiogram (ECG) should be performed to confirm the diagnosis of AF ².

Further Diagnostic Investigations for Paroxysmal AF:

• If paroxysmal AF is suspected but undetected by a 12-lead ECG, use a 24-hour ambulatory ECG monitor if asymptomatic episodes are suspected or symptomatic episodes are less than 24 hours apart ².
• If symptomatic episodes are more than 24 hours apart, an ambulatory ECG monitor, event recorder, or other ECG technology should be used for a period appropriate to detect AF ².

Assessment of Stroke and Bleeding Risks:

• Assess stroke risk using the CHA2DS2-VASc score ².
• Assess bleeding risk using the ORBIT bleeding risk score, as evidence shows it has higher accuracy in predicting absolute bleeding risk ².
• Monitor and support modification of bleeding risk factors, including uncontrolled hypertension, poor control of international normalised ratio (INR) in patients on vitamin K antagonists, concurrent medication (such as antiplatelets, selective serotonin reuptake inhibitors [SSRIs], and non-steroidal anti-inflammatory drugs [NSAIDs]), harmful alcohol consumption, and reversible causes of anaemia ².

Assessment of Cardiac Function and Underlying Heart Disease:

• Perform transthoracic echocardiography (TTE) in people with AF for whom a baseline echocardiogram is important for long-term management, or if a rhythm-control strategy (including cardioversion) is being considered ².
• TTE is also indicated if there is a high risk or suspicion of underlying structural or functional heart disease (such as heart failure or a heart murmur) that would influence subsequent management, or if refinement of clinical risk stratification for antithrombotic therapy is needed ².
• It is important not to routinely perform TTE solely for further stroke risk stratification if the need for anticoagulation therapy has already been agreed based on appropriate clinical criteria ².

Consideration of Underlying Causes:

• Consider investigating for acute, potentially reversible triggers or intercurrent illnesses, such as pneumonia or thyrotoxicosis, as these can cause new-onset AF ¹.