Slow Heartbeat

Medically Reviewed By William C. Lloyd III, MD, FACS
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What is a slow heartbeat?

A slow heartbeat is a heart rate that is below normal. The medical term for a slow heartbeat is bradycardia. The normal heart rate is 60 to 100 beats per minute. A slow heart rate is less than 60 beats per minute.

A slow heart rate may begin suddenly (acute) or develop over time (chronic). In some situations, a slow heart rate can occur as a result of chronic medical conditions.

There are many causes of a slow heartbeat, and they range from mild to serious. A slow heart rate can result from cardiovascular disorders, diseases and conditions. Athletes in excellent physical condition may have a slow heartbeat. Heat exhaustion, hypothermia, and malnutrition can also cause a slow heartbeat. Some medications may cause a slow heartbeat as a side effect.

In many cases, a slow heartbeat is not serious. However, a slow heartbeat may occur as a symptom of a serious or life-threatening condition such as a heart attack (myocardial infarction). Seek immediate medical care (call 911 ) if you, or someone you are with, experience shortness of breath, chest pain or pressure, lightheadedness or loss of consciousness, or if you think you may be having a heart attack.

If your slow heartbeat is persistent or causes you concern, seek prompt m edical care.

What other symptoms might occur with a slow heartbeat?

A slow heartbeat may accompany other symptoms, which vary depending on the underlying disease, disorder or condition. Symptoms that frequently affect the heart may also involve other body systems.

Common symptoms that may occur along with a slow heartbeat

A slow heartbeat may accompany symptoms that are related to other body systems including:

Serious symptoms that might indicate a life-threatening condition

In some cases, a slow heartbeat may be a symptom of a life-threatening condition that should be immediately evaluated in an emergency setting. Seek immediate med ical care (call 911) if you, or someone you are with, have a slow heartbeat accompanied by any of these life-threatening symptoms including:

What causes a slow heartbeat?

There are many causes of slow heartbeat, and they range from mild to serious.

Cardiovascular causes of a slow heartbeat

A slow heartbeat may be caused by cardiovascular disorders or diseases such as:

  • Cardiac arrhythmias

  • Cardiomyopathy (weakened or abnormal heart muscle and function)

  • Cardiovascular disease (due to atherosclerosis, hardening of the arteries, or other causes)

  • Sinus node disease (abnormality of the heart’s internal pacemaker)

Other causes of slow heartbeat

Other causes of slow heartbeat include:

  • Anorexia nervosa

  • Collagen vascular diseases

  • Electrolyte disturbances

  • Deep sleep

  • Excellent physical fitness

  • Fever

  • Heat exhaustion

  • Hypothermia

  • Hypothyroidism (underactive thyroid)

  • Malnutrition

  • Medication side effects

  • Old age

  • Regular exercise, which conditions the heart muscle and eventually slows the heart rate

  • Trauma

  • Tumors (intracranial, cervical, mediastinal)

Serious or life-threatening causes of slow heartbeat

In some cases, slow heartbeat may be a symptom of a serious or life-threatening condition that should be immediately evaluated in an emergency setting. These conditions include:

  • Cardiogenic shock (shock caused by heart damage and ineffective heart function)

  • Congestive heart failure (deterioration of the heart’s ability to pump blood)

  • Dissecting aortic aneurysm (life-threatening bulging and weakening of the aortic artery wall that can burst and cause severe hemorrhage)

  • Myocardial infarction (heart attack)

  • Myocarditis (infection of the middle layer of the heart wall)

  • Overdose, including cumulative overdose, of certain cardiac medications

  • Pericarditis (infection of the lining that surrounds the heart)

  • Trauma

Questions for diagnosing the cause of a slow heartbeat

To diagnose your condition, your doctor or licensed health care practitioner will ask you several questions related to your slow heartbeat including:

  • How long have you been experiencing a slow heartbeat?

  • Do you feel a regular or irregular pattern to your heartbeat?

  • Do you feel that your heartbeat is stopping or skipping?

  • When does the slow heartbeat occur? Does it coincide with any specific activities?

  • Do you have any other symptoms?

  • What medications are you taking?

What are the potential complications of slow heartbeat?

Because a slow heartbeat can be due to serious diseases, failure to seek treatment can result in serious complications and permanent damage. Once the underlying cause is diagnosed, it is important for you to follow the treatment plan that you and your health care professional design specifically for you to reduce the risk of potential complications including:

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jan 9
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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