Bradycardia

Basic Facts

  • Bradycardia is a slower than normal heart rate. The hearts of adults at rest usually beat between 60 and 100 times per minute. If you have bradycardia, your heart beats fewer than 60 times a minute. 
  • Bradycardia can be a serious problem if the heart does not pump enough oxygen-rich blood to the body.
  • Bradycardia occurs when electrical signals slow down or are blocked.

 

If you have bradycardia, your brain and other organs might not get enough oxygen, possibly causing these symptoms:

  • Near-fainting or fainting (syncope)
  • Dizziness or lightheadedness
  • Fatigue
  • Shortness of breath
  • Chest pains
  • Confusion or memory problems
  • Easily tiring during physical activity

 

 

 

 

Bradycardia can be caused by:

  • Heart tissue damage related to aging
  • Damage to heart tissues from heart disease or heart attack
  • Heart disorder present at birth (congenital heart defect)
  • Infection of heart tissue (myocarditis)
  • A complication of heart surgery
  • Underactive thyroid gland (hypothyroidism)
  • Imbalance of chemicals in the blood, such as potassium or calcium
  • Repeated disruption of breathing during sleep (obstructive sleep apnea)
  • Inflammatory disease, such as rheumatic fever or lupus
  • Medications, including some drugs for other heart rhythm disorders, high blood pressure and psychosis

 

 

 

 

To diagnose your condition, your doctor will review your symptoms and your medical and family medical history and do a physical examination.

Your doctor will also order tests to measure your heart rate, establish a link between a slow heart rate and your symptoms, and identify conditions that might be causing bradycardia.

Electrocardiogram (ECG or EKG)

An electrocardiogram, also called an ECG or EKG, is a primary tool for evaluating bradycardia. Using small sensors (electrodes) attached to your chest and arms, it records electrical signals as they travel through your heart.

Because an ECG can't record bradycardia unless it happens during the test, your doctor might have you use a portable ECG device at home. These devices include:

  • Holter monitor. Carried in your pocket or worn on a belt or shoulder strap, this device records your heart's activity for 24 to 48 hours.

    Your doctor will likely ask you to keep a diary during the same 24 hours. You'll describe any symptoms you experience and record the time they occur.

  • Event recorder. This device monitors your heart activity over a few weeks. You push a button to activate it when you feel symptoms so that it records your heart's activity during that time.

Your doctor might use an ECG monitor while performing other tests to understand the impact of bradycardia. These tests include:

  • Exercise test. Your doctor might monitor your heart rate while you walk on a treadmill or ride a stationary bike to see whether your heart rate increases appropriately in response to physical activity.

Laboratory and other tests

Your doctor will order blood tests to screen for conditions that might be contributing to bradycardia, such as an infection, hypothyroidism or an electrolyte imbalance.

If sleep apnea is suspected of contributing to bradycardia, you might undergo tests to monitor your sleep.

Treatment for bradycardia depends on the type of electrical conduction problem, the severity of symptoms and the cause of your slow heart rate. If you have no symptoms, treatment might not be necessary.

Treating underlying disorders

If a disorder such as hypothyroidism or obstructive sleep apnea is causing bradycardia, treatment of the disorder might correct bradycardia.

Change in medications

A number of medications, including some to treat other heart conditions, can cause bradycardia.

Your doctor will check what medications you're taking and possibly recommend alternatives. Changing drugs or lowering dosages might correct problems with a slow heart rate.

When other treatments aren't possible and symptoms require treatment, a pacemaker is necessary.

Pacemaker

This battery-operated device about the size of a cellphone is implanted under your collarbone. Wires from the device are threaded through veins and into your heart. Electrodes at the end of the wires are attached to heart tissues. The pacemaker monitors your heart rate and generates electrical impulses as necessary to maintain an appropriate rate.

A wireless pacemaker has been approved by the FDA. The leadless system holds promise for people who need pacing in only one ventricle, but more study is needed.