Symptoms A-Z

What is Considered a Slow Heart Rate? 10 Slow Heart Rate Causes

Understand your slow heart rate symptoms, including 7 causes & treatment options for your slow heart rate.

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Contents

  1. Symptoms
  2. Causes
  3. 7 Possible Slow Heart Rate Conditions
  4. Treatments and Relief
  5. Questions Your Doctor May Ask
  6. Statistics
  7. References

Slow Heart Rate Symptoms

As people become increasingly health-conscious, it's become more common to monitor your own vital signs at home, such as blood pressure and heart rate. Some people may have their own automated monitoring equipment or a smartwatch that detects heart rate. Others may only find out about an abnormality when they start to experience symptoms or they visit a doctor's office when routine measurements are taken. The heart is a vital organ that supplies the body with oxygenated blood, and if the heart is beating too slowly, reduced blood supply can cause a number of symptoms that should prompt a visit to a medical provider. Dysfunction of the heart itself can also be uncomfortable and should be evaluated further.

Characteristics

Some symptoms to look out for include [1]:

Slow Heart Rate Causes

A slow heart rate, or bradycardia, is diagnosed when the heart beats less than 60 times per minute [1,2]. However, having bradycardia doesn't always mean that there is an underlying medical problem requiring treatment [3]. Your physician will likely ask detailed questions about any symptoms you may be having and will review your medical history before determining if further intervention is necessary. If there is a problem, it may come from the heart directly or from some other part of the body that has an influence on heart rate. Some causes of slow heart rate are listed below, divided by category.

Normal (physiological)

Normal causes that can lead to a slower heart rate may include the following [3,4].

  • Athletic conditioning: Fundamentally, the heart is a muscle, so when it is well-trained through cardiovascular exercise, it does not need to pump as many times to supply the body with oxygen. Thus, it is common for athletes to have slow resting heart rates in the 50s or even 40s.
  • Youth: Young adults, especially young women, may have naturally low heart rates and blood pressures that do not need to be treated unless they are symptomatic.

Heart disease

Heart disease can lead to a slow heart rate in a variety of ways described here.

  • Congenital heart disease: In some cases, a slow heart rate can be a sign of a birth defect in the heart, especially if diagnosed at a young age.
  • Adult heart disease: The heart's natural pacemaker causes the heart to contract by supplying an electrical current to the muscle cells. If this is not operating properly, the heart rate can slow as backup pacemakers take over but do not fire as frequently.
  • Heart infection: Inflammation and infection of the heart, myocarditis or endocarditis, can interrupt the natural heart rhythm.
  • Heart attack: This occurs when the blood vessels that supply the heart become blocked and part of the heart muscle is damaged. A heart attack may impact the heart rate, especially if the natural pacemaker is involved.
  • Cardiac procedures: Certain procedures or surgeries to correct heart problems may injure the conduction system of the heart and cause it to contract too slowly.

Other medical causes

Other medical causes of a slow heart rate may include:

  • Medications: Many prescription medications can slow the heart rate, especially those taken for high blood pressure, such as beta blockers or for psychiatric disorders.
  • Electrolyte derangements: The body depends on precise amounts of elements like potassium and calcium in the blood, and when these electrolytes are abnormal, the heart rate can slow.
  • Hypothyroidism: Low amounts of thyroid hormone slow many body processes, including the heart rate.

7 Possible Slow Heart Rate Conditions

The list below shows results from the use of our quiz by Buoy users who experienced slow heart rate. This list does not constitute medical advice and may not accurately represent what you have.

Third degree atrioventricular nodal block

3rd degree atrioventricular nodal block is the most severe form of conduction blockage.

Rarity: Rare

Top Symptoms: shortness of breath, racing heart beat, tight, heavy, squeezing chest pain, lightheadedness, deep chest pain, behind the breast bone

Symptoms that never occur with third degree atrioventricular nodal block: swelling of one leg, swelling of one foot, swollen ankle

Urgency: Primary care doctor

Side-effect(s) of chemotherapy

Unfortunately, chemotherapy has many side-effects, ranging from hair loss to fatigue to nausea. This occurs because the treatment affects not only diseased cells but also healthy cells.

Rarity: Uncommon

Top Symptoms: fatigue, loss of appetite, arthralgias or myalgias, dizziness, sore throat

Symptoms that never occur with side-effect(s) of chemotherapy: headache resulting from a head injury

Urgency: Primary care doctor

Heart attack

Most heart attacks happen when a clot in the coronary artery blocks the supply of blood and oxygen to the heart. Often this leads to an irregular heartbeat - called an arrhythmia - that causes a severe decrease in the pumping function of the heart.

Rarity: Uncommon

Top Symptoms: chest pain, shortness of breath, tight, heavy, squeezing chest pain, being severely ill, nausea

Urgency: Emergency medical service

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Hypothyroidism

Hypothyroidism, or "underactive thyroid," means that the thyroid gland in the neck does not produce enough of its hormones. This causes a slowing of the body's metabolism.

The condition can occur due to autoimmune disease; any surgery or radiation treatment to the thyroid gland; some medications; pregnancy; or consuming too much or too little iodine. It is often found among older women with a family history of the disease.

Common symptoms include fatigue, constantly feeling cold, weight gain, slow heart rate, and depression. If left untreated, these and other symptoms can worsen until they lead to very low blood pressure and body temperature, and even coma.

Diagnosis is made through a simple blood test.

Hypothyroidism is easily managed with daily oral medication. The patient usually starts feeling better after a couple of weeks and may even lose some extra weight. It's important for the patient to be monitored by a doctor and have routine blood testing so that the medication can be kept at the correct levels.

Rarity: Rare

Top Symptoms: fatigue, depressed mood, difficulty concentrating, weight gain, muscle aches

Urgency: Primary care doctor

Myocarditis

Myocarditis is an inflammation of the heart muscle, also called the myocardium.

It is a rare complication of any viral, bacterial, parasitic, or fungal infection. Reaction to drugs, medications, chemicals, or even radiation can bring about myocarditis.

Anyone with a weakened immune system or pre-existing heart condition is susceptible.

Symptoms include fatigue, chest pain, and shortness of breath, especially following a viral upper respiratory illness. Swelling of the feet and legs from poor circulation may be seen.

If symptoms are severe, take the patient to the emergency room or call 9-1-1. Myocarditis weakens the heart so that it cannot pump blood as it should. Blood clots, stroke, heart attack, abnormal heart rhythm (arrhythmia,) and sudden cardiac death can result without treatment.

Diagnosis is made by electrocardiogram (ECG,) chest x-ray, MRI, echocardiogram, and blood tests.

Short-term treatment is with rest and medication, depending on what kind of illness brought about the myocarditis. Sometimes, devices to support the heartbeat may be surgically implanted.

Long-term treatment may involve medicines such as ACE inhibitors, ARBs, beta blockers, and diuretics.

Rarity: Rare

Top Symptoms: fatigue, headache, shortness of breath, muscle aches, chest pain

Urgency: Hospital emergency room

Beriberi (adult)

A low level of vitamin B1 (thiamin) can cause damage to the heart, brain and nerves. This can result in symptoms like weakness, amnesia, nerve pain and symptoms of heart failure like swelling of limbs and shortness of breath.

Rarity: Ultra rare

Top Symptoms: abdominal pain (stomach ache), shortness of breath, anxiety, chest pain, distal numbness

Urgency: Hospital emergency room

Moderate to severe hypothermia

With prolonged exposure to freezing cold, the body can lose the ability to maintain a safe core temperature. If this continues for long enough, you can become confused or even lose consciousness

Rarity: Ultra rare

Top Symptoms: coldness, alertness level change, pale skin, slow heartrate (under 60bpm)

Symptoms that never occur with moderate to severe hypothermia: shivering

Urgency: Emergency medical service

Slow Heart Rate Treatments and Relief

Since there are many causes of a slow heart rate, your physician will likely start with a thorough evaluation that may include monitoring over a period of hours to days. This will help determine if your heart rate is normal or if it will require treatment, some of which are listed below.

What to expect at your appointment

While being evaluated or in preparation of being evaluated, the following should occur [5].

  • Note your symptoms: Your physician will want to know the type and frequency of any symptoms you are experiencing, so it's best to keep a diary. Notable symptoms include palpitations, dizziness, fainting, chest pain, shortness of breath or reduced ability to exercise.
  • Review family history: Certain cardiac conditions run in the family, so your physician will want to know about any relatives who died suddenly or have diagnosed cardiac problems.
  • EKG: This simple test measures the electric current as it runs through your heart and provides very important information to your physician. It's painless, takes just seconds, and involves only a few pads that will be placed on your chest.
  • Holter monitor: This is a portable EKG-like machine that you can wear for several days during your everyday activities. This will enable your physician to monitor your heart rate and rhythm over a longer period of time and potentially find any abnormalities that could be missed in the office. Loop recorders are also used for more prolonged monitoring.
  • Echocardiogram: In some cases, yourphysician will order an ultrasound to examine the structure of the heart, including the valves and strength of contraction.

Medical treatments

Your physician may prescribe the following depending on the cause of your slow heart rate.

  • Medications: Some medications will raise the heart rate or treat any arrhythmias that may be the underlying cause of your slow heart rate.
  • Artificial or external pacemaker: In certain cases, a physician will decide to insert a pacemaker in the heart. This provides a regular electrical current to the heart so that it contracts regularly and at a healthy rate and rhythm. Some pacemakers operate continuously while others only "kick in" when the heart rate falls below a set threshold rate.

Questions Your Doctor May Ask About Slow Heart Rate

To diagnose this condition, your doctor would likely ask the following questions:

  • Have you been feeling more tired than usual, lethargic or fatigued despite sleeping a normal amount?
  • Do you notice your heart beating hard, rapidly, or irregularly (also called palpitations)?
  • Have you been experiencing dizziness?
  • Have you ever been diagnosed with cancer?

The above questions are also covered by our A.I. Health Assistant.

If you've answered yes to one or more of these questions

Take a quiz to find out what might be causing your slow heart rate

Slow Heart Rate Symptom Checker Statistics

People who have experienced slow heart rate have also experienced:

  • 9% Dizziness
  • 6% Heart Rate Precursor
  • 5% Fatigue

People who have experienced slow heart rate were most often matched with:

  • 50% Heart Attack
  • 28% Third Degree Atrioventricular Nodal Block
  • 21% Side-Effect(S) Of Chemotherapy

Source: Aggregated and anonymized results from visits to the Buoy AI health assistant (check it out by clicking on “Take Quiz”).

Slow Heart Rate Symptom Checker

Take a quiz to find out what might be causing your slow heart rate

References

  1. Bradycardia: Slow Heart Rate. American Heart Association. Updated September 30, 2016. AHA Link
  2. Bradycardia. University of Rochester Medical Center. URMC Link
  3. Is a Low Heart Rate Worrisome? Harvard Medical School: Harvard Health Publishing. Published October 2015. Harvard Health Publishing Link
  4. Thompson EG, Gabica MJ, Romito K, Husney A, Miller JM, eds. Bradycardia (Slow Heart Rate). C.S. Mott Children's Hospital. Updated December 6, 2017. Mott Children's Hospital Link
  5. Common Tests for Arrhythmia. American Heart Association. Updated September 30, 2016. AHA Link

Disclaimer: The article does not replace an evaluation by a physician. Information on this page is provided as an information resource only, and is not to be used or relied on for any diagnostic or treatment purposes.