Tachycardia is a condition in which the heart beats faster than normal, typically exceeding 100 beats per minute in adults at rest. It can result from exercise, stress, fever, anemia, heart disease, or abnormalities in the heart's electrical conduction system. Symptoms may include palpitations, dizziness, shortness of breath, chest pain, or fainting, although some individuals may have no symptoms. Treatment depends on the underlying cause and may include lifestyle changes, medications, or procedures such as catheter ablation in persistent or severe cases.