Low Heart Rate (Bradycardia)

What Is Bradycardia?

Bradycardia causes

Problems with your heart’s conduction system cause bradycardia. Specifically, you can develop a slow heart rate if your heart’s natural pacemaker isn’t working as expected (sinus node dysfunction) or signals have trouble traveling from your upper to lower heart chambers (heart block). These are electrical issues — just like when your home Internet is slow or signals can’t get through to your TV.

Lots of things can disrupt your heart’s electrical activity, leading to bradycardia, including:

• Age-related changes to your heart’s conduction system, especially after age 70 
• Chronic inflammatory conditions, like rheumatoid arthritis, scleroderma, sarcoidosis and lupus
• Complications from heart procedures or surgeries, like catheter ablation, valve surgery, septal myectomy and congenital heart disease surgery
• Conditions that make substances build up in your organs, like amyloidosis and hemochromatosis
• Electrolyte imbalances, like having too much or too little potassium in your body
• Heart conditions, like cardiomyopathy, congenital heart disease, heart failure or heart attacks 
• Infections, like Lyme disease, Chagas disease, diphtheria, infective endocarditis and toxoplasmosis
• Medications, like beta-blockers, calcium channel blockers, antiarrhythmic drugs, digoxin, opioids, tricyclic antidepressants and lithium
• Obstructive sleep apnea, which can make your heart rate go down when you’re sleeping
• Underactive thyroid, which means your thyroid gland doesn’t make or release enough of a certain hormone

How doctors diagnose this condition

Healthcare providers diagnose bradycardia through a physical exam and testing. During the exam, they’ll review your medical history and ask about any symptoms. Be prepared to share details like how often you have symptoms, how long they last and what seems to trigger them.

For example, you might notice symptoms during exercise, when you shift positions, after you eat or after you take certain medicines. Keep notes on how and when heart rate changes happen. That info can help your provider make a diagnosis.

Tests that are used

An electrocardiogram (ECG/EKG) is a key test that providers use to diagnose bradycardia. But it only tracks your heart’s electrical activity for less than a minute. This means it might not capture a low heart rate episode as it’s happening. For this reason, your provider may recommend ambulatory monitoring. This means you wear a device as you go about your daily routine.

Other tests you might need include:

• Blood tests to measure electrolyte levels, thyroid hormone levels and more
• Echocardiogram to check your heart’s structure and function
• Exercise stress test to evaluate symptoms that occur along with exercise
• Sleep study to check for sleep apnea

How is bradycardia treated?

Treatment for a low heart rate depends on the cause and how it’s affecting your body. There are so many different causes of bradycardia that providers need to tailor treatment to your needs. It may be as simple as switching up your usual medicines. Or you might need to take new medicines or have a procedure to fix an issue with your heart.

In general, to treat bradycardia, your provider may:

• Change your medications: If a medicine you’re taking for another reason is causing bradycardia, your provider may switch you to another or lower your dose. Never make any changes to your medicines on your own.
• Treat an underlying condition: Depending on the condition, you may need medicines, procedures or surgeries. These can treat or even cure the issue that’s causing your low heart rate. Your provider will explain the best treatment plan for your needs.
• Give you medicine to raise your heart rate: In emergency situations, providers can give you medicine (like atropine) through an IV to speed up your heart rate. This treatment happens in a hospital with providers closely monitoring you.
• Give you a permanent pacemaker: This is a device cardiologists place in your chest to normalize your heart rate and relieve symptoms. You might need one when you have a slow heart rate because of age or certain conditions.

If you’re otherwise healthy and don’t have symptoms, you may not need treatment for bradycardia. This is the case with athletes who naturally have a low heart rate.

When should I see my healthcare provider?

You should see your healthcare provider for an annual physical, whether you have bradycardia or not. These visits let your provider catch many health problems early, especially ones that don’t have symptoms you can feel.

If you’ve been diagnosed with bradycardia, your provider will tell you how often to come back for appointments. Always call your provider right away if you have new or changing symptoms.

When should I seek emergency care?

Call 911 or your local emergency services number if:

• You have a low heart rate along with symptoms like chest pain, heart palpitations, trouble breathing or dizziness
• Your heart rate falls below 40 beats per minute (and this isn’t usual for you)

What can I expect if I have this condition?

Bradycardia is treatable and often curable. If you have bradycardia because of another condition, treating that condition may be all it takes to get your heart rate back to normal. In general, you’re more likely to have a good outcome with early diagnosis and treatment.

Bradycardia may be temporary or something you manage for the rest of your life. It depends on the cause. Your provider can tell you more about what to expect.

When should I worry about bradycardia?

If your heart rate is slow (40 to 60 bpm) but you don’t have symptoms, there’s usually no reason to worry. But you should still tell your healthcare provider so they can make sure there’s nothing going on that needs treatment.

If your heart rate drops into the 30s, that’s getting into dangerous territory. You might not get enough oxygen to your brain. This can cause fainting, lightheadedness and shortness of breath. Seek medical attention right away.