When should you worry about abnormal heartbeats?

People commonly experience heart palpitations, which feel like the heart flutters or skips a beat, or beats at a faster rate or in an irregular rhythm. They often last only seconds and can be unsettling. For the most part, palpitations are nothing to worry about. Still, these unusual heart sensations may indicate something more serious, such as atrial fibrillation, supraventricular tachycardia, or ventricular tachycardia. Palpitations that persist or cause other symptoms (such as lightheadedness) should be evaluated by a doctor.