What Is Bradycardia?
It's a slow heart rate, usually under 60 beats a minute. It can be very serious, as it means your heart doesn't pump enough oxygen-rich blood to your body. It can make you feel dizzy, weak, or short of breath. Sometimes, there are no symptoms. If your bradycardia is severe, you may need a pacemaker.
But a slow heart rate isn't always a problem. Your heart rate slows down while you sleep. And a rate of 40-60 beats a minute is common in healthy athletes.
However, it may be a clue that you have an issue with the electrical system in your heart, which can cause symptoms.
Bradycardia vs. tachycardia
Both are problems with your heart rhythm. Bradycardia is a slower-than-usual heart rhythm, and tachycardia is a faster-than-usual heart rhythm, usually more than 100 beats a minute.
Heart Basics
Your heart has four chambers, two on the top called atria and two on the bottom called ventricles.
In your upper right atrium, you have a group of cells called the sinus node. It makes the electrical signals that tell your heart to beat. If these signals slow down or are blocked, the time between your heartbeats also slows down.
Types of Bradycardia
Sinus bradycardia
This is the most common form of bradycardia. It's when your heart slows down to less than 60 beats per minute. This could be normal for you, especially if you're athletic. You probably don't need treatment unless you have symptoms.
Sinus bradycardia is unlikely to cause you complications unless your heart rate goes below 40 beats per minute. If your heart rate goes this low, your doctor may call it junctional bradycardia.
Sinus pause (also known as sinus arrest)
If you have a sinus pause, your sinus node doesn't trigger your heart to beat every once in a while, so your heart may miss one or more beats.
You may have symptoms if your heart skips beats often or over an extended period. There may also be a risk of complications with this type of bradycardia.
Sick sinus syndrome
When your sinus node doesn't work well, you may develop sick sinus syndrome. You may have a slow heart rate or a combination of a fast and slow heart rate.
Tachy-brady syndrome
This type of bradycardia often happens in people with atrial fibrillation. It's caused by damage to your sinus node. It makes your heart rate alternate between too fast and too slow.
You may have symptoms such as palpitations, lightheadedness, or fainting. You may also have more problems and a higher risk of stroke.
Heart block
This happens when something blocks the signals from your sinus node, so your heart rate slows down.
Bradycardia Symptoms
You may or may not have symptoms with bradycardia, especially if you have a high level of fitness.
Bradycardia symptoms include:
- Chest pain (angina)
- Feeling very tired (fatigue)
- Heart palpitations (a fluttering feeling in your chest or being aware of your own heartbeat)
- Shortness of breath
- Memory problems, confusion, or trouble concentrating
- Dizziness, lightheadedness, or fainting
- Crankiness, agitation, or other personality changes
When to See a Doctor
A slow heart rate, new or changing symtpoms, or any symptoms that worry you are reasons to see your doctor.
You should call 911 and go to the emergency room if you have any of the following symptoms:
- Chest pain lasting more than a few minutes
- Shortness of breath or trouble breathing
- Dizziness, lightheadedness, and fainting spells
Go to the ER if you have symptoms that come on quickly or get worse.
Low Heart Rate Causes
Bradycardia can be caused by many conditions. Some common ones are:
- Not getting enough electrolytes in your diet, especially calcium, magnesium, and potassium
- Anorexia nervosa, an eating disorder
- Inflammation in your heart (myocarditis), the inner lining of your heart (endocarditis), or the sac that holds your heart (pericarditis)
- Infections, such as strep throat, which can damage your heart valves
- Rheumatic fever or rheumatic heart disease (which may be another complication of strep throat)
- Lyme disease, which is an infection you can get from a tick bite
- Chagas disease, which is an infection you can get from a kissing bug bite
- Certain medications, such as beta-blockers, calcium channel blockers, anti-arrhythmia drugs, narcotics, lithium, depressants, or cannabis
- Heart surgery, such as valve repair and replacement
- Radiation therapy
Bradycardia Risk Factors
Anything that increases your risk of having heart problems can increase your risk of bradycardia, such as:
- Older age
- High blood pressure
- Smoking
- Heavy alcohol use
- High levels of stress and anxiety
- Using recreational drugs, especially narcotics and cannabis (marijuana)
Bradycardia Diagnosis
Your doctor will likely diagnose you based on a physical exam and tests, such as:
EKG. This test measures your heart's electrical activity using sensors (electrodes) that stick to the skin of your chest. These electrodes sense the electrical activity of your heart. It is the most important test your doctor will use to diagnose if you have bradycardia.
Holter monitor. This is a wearable version of an EKG, which records your heart's activity continuously over about 24 hours so your doctor can see your heart's rhythm over a longer time.
Event recorder. This is like a Holter monitor, but it records only at specific times for a few minutes. You may need to push a button whenever you notice symptoms, or the recorder may be set to automatically record whenever it detects a low heart rate.
Tilt table test. Your doctor may order this test if your bradycardia is causing fainting spells. It changes your position from lying down to standing and lets your doctor see if this change triggers a fainting spell.
Stress exercise test. Your doctor may order this test to see how your heart does while you ride an exercise bike or walk on a treadmill.
Sleep study. Your doctor may order this test to see if you have obstructive sleep apnea that is causing your slow heart rate.
Blood tests. They detect things such as:
- Electrolyte levels, especially calcium, potassium, and magnesium
- Thyroid hormone levels (Low thyroid hormone levels can cause bradycardia.)
- Troponin, which is a protein made by your heart when it has been damaged
- Drugs that cause heart damage or bradycardia, in a test called a toxicology screen
Bradycardia Treatment
If you have bradycardia but don't have the symptoms, you likely won't need any treatment. If you do have symptoms, the treatment plan will be based on the likely cause of the problem. For instance, if the cause is hypothyroidism, or low thyroid function, treating that may take care of your slow heart rate. Or, your doctor may change medications that you take that might be slowing your heart. For instance, beta-blockers are sometimes prescribed to relax your heart muscle. But if they cause you to have a really slow heart rate, your doctor might lower your dose or give you a different drug.
Otherwise, your doctor may treat your bradycardia with:
Medication
If your heart rate is dangerously low, your doctor may treat you in the hospital with an IV drug, such as atropine, to speed up your heart rate.
Temporary pacemaker
Your doctor may fit you with a device with electric contacts that attach to the skin of your chest. This device sends mild electrical currents into your body that cause your heart to beat.
Permanent pacemaker
If you have a sick sinus syndrome, your heart's natural pacemaker doesn't work, so you may need surgery to implant a permanent pacemaker into your chest. Leadless pacemakers are now available, which your surgeon can insert with a minimally invasive procedure. These pacemakers are very small, and you will usually need less recovery time after one is inserted.
Bradycardia Prevention
The best way to prevent bradycardia is to protect yourself from getting heart disease. The following steps can help prevent heart disease:
- See your doctor for regular checkups.
- Take medicines exactly as prescribed by your doctor.
- Exercise regularly.
- Eat a low-fat, low-salt, low-sugar diet rich in fruits, vegetables, and whole grains.
- Maintain a healthy weight.
- Keep your blood pressure and cholesterol under control.
- Don't smoke.
- If you drink alcohol, have no more than one to two drinks a day, depending on your body weight.
If you have heart disease, some steps you can take to lower your risk of getting bradycardia include:
- Following your doctor's treatment plan
- Reporting any new symptoms or changes in your symptoms to your doctor as soon as possible
Takeaways
Bradycardia is a heart rate of less than 60 beats per minute. This may not cause any problems or symptoms, and it may be a result of you being highly physically fit. You should go to the emergency room (ER) if you have symptoms such as chest pain, shortness of breath, or dizziness. Your doctor may be able to treat bradycardia by changing your medicines, if that's the cause. In severe cases, you may need a pacemaker, which can be temporary or permanent.
