Symptoms and Complications
When the heart beats faster than normal, it's called tachycardia. Symptoms include chest discomfort, palpitations, lightheadedness, dizziness, and sometimes fainting. When it beats slower than normal, it's called bradycardia. Bradycardia can cause fatigue, lightheadedness, dizziness, and fainting, as it tends to produce low blood pressure.
Everyone knows what it feels like to experience an occasional flutter of the heart, and usually it doesn't mean anything. But if you get chest pains or feel faint, or when checking your pulse you notice it to be irregular over a prolonged period, it's time to see a doctor.