26th May 2025

A 71-year-old is admitted to A&E with a collapse.

A 71-year-old is admitted to A&E with a collapse. She is drowsy and is unable to give a history. Her daughter reports she has a recent history of these episodes that seem to happen throughout the day. She has a background of CVA, HTN and Osteoarthritis. She does not drink any alcohol.  

On examination she is apyrexial and haemodynamically stable. BP 144/59.

Admission bloods show: Hb 113, WCC 9.9, MCV 96. CRP 41. UE normal. Glucose 2.4mmol/L. 

ECG shows atrial fibrillation

What is the most important next step in investigation?

Select the SINGLE most appropriate option from the list below. Select ONE option only.