Bradycardia

Basic Facts

  • Bradycardia is a slower than normal heart rate. Resting heart rate for adults is usually 60-100 beats per minute. Bradycardia is a resting heart rate slower than 60 bpm. 
  • Bradycardia occurs when electrical signals slow down or are blocked.
  • Bradycardia can be a serious problem if the heart does not pump enough oxygen-rich blood to the body.

If the bradycardia is too slow to maintain an adequate blood pressure, the brain and other organs might not get enough oxygen (especially if there is underlying heart disease), causing the following possible symptoms:

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

Bradycardia can be caused by:

  • 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
  • Also occurs in "Athlete's heart" due to a training effect; however, this is a harmless condition with no symptoms. 

 

 

 

 

Listening to the patient describe symptoms, and conducting a physical examination, the healthcare provider may also recommend:

  • ECG – noninvasive test, stickers attached to wires placed on the chest, provides a 6 second “snapshot” of heart’s electrical activity. Can be done at a visit and will show bradycardia if it is occurring at the time. 

  • Holter monitor / Cardiac ambulatory monitoring – wearable ECG that can record the heart's activity constantly for days to weeks, “movie v snapshot”. Can be applied by the patient or at a visit. Paired with provided smartphone that stores/sends data. Worn 24/7. Returned via UPS. 

  • Exercise stress test. Patient’s heart rate is monitored while walking on a treadmill to see whether the heart rate increases appropriately in response to physical activity. 

  • Labs – 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 Diagnosis can be difficult because bradycardia may come and go.

 

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

Treating underlying disorders

If an underlying disorder such as hypothyroidism, electrolyte imbalance, or obstructive sleep apnea is causing bradycardia, treatment of the disorder might correct it.

Change in medications

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

Your healthcare provider will check what medications you're taking and possibly recommend dose changes or alternatives to correct problems with a slow heart rate.

When other treatments aren't possible and symptoms require treatment, a pacemaker is necessary. Artificial pacemakers monitor your natural heart rate and generate electrical impulses as necessary to maintain an appropriate rate.