Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia seen in clinical practice. It is a perennial hot topic for General Practitioners and remains a very common source of MRCGP exam questions. The diagnosis and management of AF presents some serious challenges, and there have been several significant new developments over recent years. It remains an important contributor to population morbidity and mortality, being particularly common in the elderly, and growing in prevalence with the ageing of the population.