Find out more about the symptoms, diagnosis and treatment of a slower than typical heartbeat.
Bradycardia (brad-e-KAHR-dee-uh) is a slow heart rate. The hearts of adults at rest usually beat between 60 and 100 times a minute. If you have bradycardia, your heart beats fewer than 60 times a minute.
Bradycardia can be a serious problem if the heart rate is very slow and the heart can't pump enough oxygen-rich blood to the body. If this happens, you may feel dizzy, very tired or weak, and short of breath. Sometimes bradycardia doesn't cause symptoms or complications.
A slow heart rate isn't always a concern. For example, a resting heart rate between 40 and 60 beats a minute is quite common during sleep and in some people, particularly healthy young adults and trained athletes.
If bradycardia is severe, an implanted pacemaker may be needed to help the heart maintain an appropriate rate.
A slower than typical heartbeat (bradycardia) can prevent the brain and other organs from getting enough oxygen, possibly causing these signs and symptoms:
Many things can cause signs and symptoms of bradycardia. It's important to get a prompt, accurate diagnosis and appropriate care. See your health care provider if you are concerned about a slow heart rate.
If you faint, have difficulty breathing or have chest pain lasting more than a few minutes, call 911 or emergency medical services.
Bradycardia can be caused by:
To better understand the causes of bradycardia, it may be helpful to know how the heart typically beats.
The typical heart has four chambers — two upper chambers (atria) and two lower chambers (ventricles). Within the upper right chamber of the heart (right atrium) is a group of cells called the sinus node. The sinus node is the heart's natural pacemaker. It produces the signal that starts each heartbeat.
Bradycardia occurs when these signals slow down or are blocked.
Bradycardia often starts in the area of the heart called the sinus node. In some people, sinus node problems cause alternating slow and fast heart rates (bradycardia-tachycardia syndrome).
Bradycardia can also occur if the heart's electrical signals don't move correctly from the upper chambers (atria) to the lower chambers (ventricles). If this occurs, the condition is called heart block, or atrioventricular block.
Heart blocks fall into three main groups.
In a typical heart rhythm, a tiny cluster of cells at the sinus node sends out an electrical signal. The signal then travels through the atria to the atrioventricular (AV) node and into the ventricles, causing them to contract and pump blood.
Bradycardia is often associated with damage to heart tissue from some type of heart disease. Anything that increases the risk of heart problems can increase the risk of bradycardia. Risk factors for heart disease include:
Healthy-lifestyle changes or medical treatment may help lower the risk of heart disease.
Possible complications of bradycardia can include:
Bradycardia can be caused by certain medications, particularly if they are taken at high doses, so it's important to take all medications as directed. Although bradycardia is not typically preventable, health care providers recommend strategies to reduce the risk of developing heart disease. Take the following heart-healthy steps:
If you already have heart disease, there are steps you can take to lower your risk of developing bradycardia or another heart rhythm disorder:
To diagnose bradycardia, a health care provider will usually perform a physical exam and listen to your heart with a stethoscope. He or she may ask you questions about your symptoms and medical history.
Your health care provider may recommend tests to check your heart rate and see if you have a heart problem that can cause bradycardia. Blood tests may be done to check for other conditions that can cause slow heartbeats, such as an infection, an underactive thyroid (hypothyroidism) or an electrolyte imbalance.
An electrocardiogram (ECG or EKG) is the main test used to diagnose bradycardia. An ECG measures the electrical activity of the heart. Sticky patches (electrodes) are placed on the chest and sometimes the arms and legs. Wires connect the electrodes to a computer, which displays the results. An ECG can show if the heart is beating too slow, too fast or not at all.
Because an ECG can't detect bradycardia unless the slow heartbeat occurs during the test, your health care provider might recommend a portable ECG device. Portable ECG devices include:
An ECG may be done with other tests to understand how bradycardia affects you. These tests include:
A sleep study may be recommended if your health care provider thinks that repeated pauses in breathing during sleep (obstructive sleep apnea) are causing bradycardia.
Treatment for bradycardia depends on the severity of symptoms and the cause of the slow heart rate. If you don't have symptoms, treatment might not be necessary.
Bradycardia treatment may include lifestyle changes, medication changes or an implanted device called a pacemaker. If an underlying health problem, such as thyroid disease or sleep apnea, is causing the slow heart rate, treatment of that condition might correct bradycardia.
Many medications, including those used to treat other heart conditions, can cause bradycardia. Always let your health care provider know about all the medications you take, including those bought without a prescription.
If a medication you're taking is causing bradycardia, your health care provider may recommend a lower dosage or a different medication.
When other treatments aren't possible and bradycardia symptoms are severe, a device called a pacemaker is necessary to control the heart rhythm. Pacemakers work only when needed. When the heart beats too slowly, the pacemaker sends electrical signals to the heart to speed up the beat.
Having a pacemaker implanted requires a surgical procedure. One or more wires are inserted into a major vein under or near the collarbone and guided to the heart using X-rays as a guide. One end of each wire is secured at the appropriate area in the heart, while the other end is attached to a device (pulse generator) implanted under the skin beneath the collarbone.
A leadless pacemaker is smaller and typically requires a less invasive surgery to implant the device.
Whether you start by seeing your primary care provider or get emergency care, you'll likely be referred to a doctor trained in heart conditions (cardiologist) for diagnosis and treatment.
If possible, write down the following information and take it with you to your health care provider's appointment:
If possible, take along a family member or friend to help you remember the information you receive.
For bradycardia, basic questions to ask your health care provider include:
Don't hesitate to ask other questions.
Your health care provider is likely to ask you questions, such as: