The lifetime risk of atrial fibrillation (AF) for men and women over the age of 40 is about 25%. The condition affects around 800,000 people in the UK, of which it is estimated that 250,000 are undiagnosed. A rapid heart rate may result in palpitations, dyspnoea or chest tightness, whereas loss of atrial contractility may lead to fatigue and reduced exercise capacity. In patients with a confirmed diagnosis of AF, three areas need to be considered: stroke risk, symptoms, and risk of tachycardia cardiomyopathy.