Atrial fibrillation is a type of cardiac arrhythmia, primarily feared for its potential to form blood clots within the heart. These clots can travel to other organs via the bloodstream, most commonly to the brain. Additionally, pieces of these clots can also travel to coronary arteries causing myocardial infarction, leading to organ embolism wherever they lodge. Generally, if no blood clots are formed, many individuals with atrial fibrillation may not experience symptoms. However, if combined with other cardiac conditions such as heart failure or coronary artery disease, atrial fibrillation can exacerbate the risk of developing these heart diseases. Thus, atrial fibrillation on its own is not severe but becomes concerning when associated with other cardiac conditions, increasing the risk of other heart diseases. If atrial fibrillation occurs with left or right accessory pathways, it may also lead to ventricular fibrillation, resulting in sudden death of the patient. Moreover, if the atrial fibrillation has no apparent cause, and the heart structure is normal with no symptoms, then such isolated atrial fibrillation does not typically form blood clots and is considered relatively mild.