Background               A supraventricular tachyarrhythmia, with chaotic and irregular conduction of depolarisation through the atrium and then ventricles. Caused by PIRATES. Cardiorespiratory: P ulmonary: PE, pleural effusion, COPD, lung cancer, pneumonia. I schaemic heart disease (inc. acute MI) and other cardiac diseases: HTN, HF, cardiomyopathy, pericardial disease, myxoma. R heumatic valve disease and mitral stenosis. Toxic and metabolic: A lcohol ('holiday heart'), smoking, caffeine. T hyrotoxicosis E lectrolyte abnormalities (↓K + ,↓Mg 2+ ). S ugar (diabetes),  S epsis. 'Lone AF' if it is idiopathic. Epidemiology Commonest arrhythmia, affecting 10% over 80 years old. Commoner in men. Classification by timeframe Acute AF Onset within previous 48 hrs, either 'new-onset' or a recurrent episode. Chronic AF Sub-classified as: Paroxysmal AF: self-terminates <7 days, usually 48 hrs. Persistent AF...