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, feel faint, or you notice your pulse to be irregular or either very rapid or very slow over a prolonged period, it's time to see a doctor.