Having bradycardia (say "bray-dee-CAR-dee-uh") means your heart beats very slowly. For most people, a heart rate of 60 to 100 beats a minute is considered normal. If your heart beats less than 60 times a minute, your doctor may diagnose bradycardia. A slow heart rate is sometimes normal and can be a sign of being very fit. Healthy young adults and athletes often have heart rates of less than 60 beats a minute.

Diseases that damage the heart's electrical system. These include coronary artery disease, heart attack, and infections such as endocarditis. Conditions that can slow electrical impulses through the heart. Examples include having a low thyroid level (hypothyroidism) or an electrolyte imbalance, such as too much potassium in the blood. Some medicines for treating heart problems or high blood pressure, such as beta-blockers, antiarrhythmics, and digoxin.

Your doctor may be able to diagnose bradycardia by doing a physical exam, asking questions about your past health, and doing an electrocardiogram (EKG or ECG). An EKG measures the electrical signals that control heart rhythm, so it is the best test for bradycardia. But bradycardia often comes and goes, so a standard EKG done in the doctor's office may not find it. An EKG can identify bradycardia only if you are actually having it during the test.

Bradycardia is often the result of another heart condition, so taking steps to improve your heart health will usually improve your overall health. The best steps you can take are to: People who get pacemakers need to be careful around strong magnetic or electrical fields, such as MRI machines or magnetic wands used at airports. If you get a pacemaker, your doctor will give you information about the type you have and what precautions to take.

Call 911 or other emergency services immediately if you have a slower-than-usual heart rate and experience any of the following: Notice increased shortness of breath or swelling in your feet and ankles. These may be early symptoms of heart failure. If you have symptoms that may be caused by a slow heart rate, taking a wait-and-see approach, which is called watchful waiting, is not appropriate.

Treatment for bradycardia depends on its underlying cause, whether it is causing symptoms, and whether it is likely to get worse. Once your doctor knows the exact cause of your slow heart rate, he or she will determine which treatment you need. Typically, bradycardia needs to be treated if it is causing symptoms such as fainting or severe, disabling fatigue.

Sustained sinus bradycardia or tachycardia is defined by more than 30 seconds of a stable rhythm to distinguish it from transient responses associated sleep disordered breathing events or arousals.