A racing, erratic pulse above 100bpm may be what makes the patient seek medical help, but diagnosing AF also needs an electrocardiogram showing an episode of AF occurring, usually recording at least 30 seconds. If the AF is paroxysmal, the patient may need to wear an ambulatory ECG recorder to capture an episode.6,7

An echocardiogram (heart ultrasound), chest x-ray (for pulmonary influences) and blood tests (for anaemia, kidney function and thyroid activity) will also be carried out.

Heart failure may have more presenting symptoms, but diagnosis will involve similar tests: ECG, echocardiogram, blood tests, chest x-ray, urinalysis and breathing tests including spirometry and peak flow measurements to assess the lung condition. An x-ray can indicate an enlarged heart, fluid on the lungs or other lung conditions which may be causing symptoms.9,11

Blood tests will include measuring N-terminal pro-B-type natriuretic peptide (NT-proBNP), a hormone which can be elevated in heart failure.13,17