Atrial fibrillation (AF or A-fib) is an abnormal hea rhythm characterized by rapid and irregular beating of the atrial chambers of the hea. Often it stas as brief periods of abnormal beating which become longer and possibly constant over time.Often episodes have no symptoms. Occasionally there may be hea palpitations, fainting, lightheadedness, shoness of breath, or chest pain.The disease is associated with an increased risk of hea failure, dementia, and stroke. It is a type of supraventricular tachycardia Leads V4 and V5 of an electrocardiogram showing atrial fibrillation with somewhat irregular intervals between hea beats, no P waves, and a hea rate of about 150 BPM. High blood pressure and valvular hea disease are the most common alterable risk factors for AF. Other hea-related risk factors include hea failure, coronary aery disease, cardiomyopathy, and congenital hea disease. In the developing world valvular hea disease often occurs as a result of rheumatic fever. Lung-related risk factors include COPD, obesity, and sleep apnea.Other factors include excess alcohol intake, tobacco smoking, diabetes mellitus, and thyrotoxicosis. However, half of cases are not associated with any of these risks.A diagnosis is made by feeling the pulse and may be confirmed using an electrocardiogram (ECG).A typical ECG in AF shows no P waves and an irregular ventricular rate Ref Harrison 20th edition pg 1456