Your heartbeat is controlled by electrical impulses in your heart. When the impulses don’t work like they’re supposed to, it causes a heartbeat that’s too fast, too slow or irregular. This is called an arrhythmia or heart rhythm disorder. Some types of arrhythmias are harmless, but some can be life-threatening.

Arrhythmias don’t always have symptoms. When they do, you may feel your heart racing, beating too slowly, or beating irregularly without a clear reason. More serious signs can be weakness, fainting, shortness of breath, chest pain or sweating.

If you have these symptoms, talk to your doctor. Your doctor may refer you to an electrophysiologist — a cardiologist who specializes in arrhythmias. If you or a loved one is experiencing an emergency call 911 immediately.