Atrial fibrillation is usually accompanied by symptoms associated with a rapid heart rate. A fast and irregular heart rate may be perceived as a feeling of a heartbeat that is too fast, irregular, or skipping (palpitations) or as intolerance to exercise, sometimes leading to anginal chest pain ( If your heart beats faster and your heart beats worse). Other possible symptoms include heart failure symptoms such as fatigue, shortness of breath, and swelling. Abnormal heart rhythms (arrhythmias) may only be identified by the onset of a stroke or transient ischemic attack (TIA). Atrial fibrillation is not uncommonly first noticed during a routine physical examination or electrocardiogram. Most cases of atrial fibrillation suggest other medical problems, chest pain or angina, signs, and symptoms of hyperthyroidism (hyperthyroidism) such as weight loss or diarrhea, and lung disease Because it is symptomatic, it may indicate an underlying cause. As with hypertension, diabetes, heart failure, or rheumatic fever, a history of stroke or TIA may indicate whether people with atrial fibrillation are at increased risk for complications.