Atrial fibrillation is the abnormal rhythm of the heart, which is characterized by rapid and irregular beating of the atria. It often begins as brief periods of abnormal beating, and gets longer and fairly constant over time. It is associated with an increased risk of dementia, stroke and heart failure. Although symptoms are generally absent, occasionally there may be cases of lightheadedness, chest pain, heart palpitations and shortness of breath. Atrial fibrillation can be diagnosed by an investigation of the complete patient profile, including medical history and physical examination, transthoracic echocardiogram, electrocardiogram, serum thyroid stimulating hormone level, etc. It can be treated with medications that work to slow down the heart rate to acceptable rates or convert the heart rhythm to a normal sinus rhythm. Electrical cardioversion, ablation and anti-clotting medications like direct oral anticoagulants and warfarin may be recommended. This book aims to shed light on some of the unexplored aspects of atrial fibrillation. It includes some of the vital pieces of work being conducted across the world, on atrial fibrillation and clinical cardiology. It is a vital tool for all researching or studying cardiology as it gives incredible insights into emerging trends and concepts.