Table of ContentsView AllTable of ContentsWhat Is It?SymptomsIs It Serious?CausesDiagnosisTreatmentWhen to See a Healthcare ProviderFrequently Asked Questions
Table of ContentsView All
View All
Table of Contents
What Is It?
Symptoms
Is It Serious?
Causes
Diagnosis
Treatment
When to See a Healthcare Provider
Frequently Asked Questions
Bradycardia is a heart rate that’s slower than normal. There are two main types of bradycardia—sinus bradycardia and heart block.
Sinus bradycardia is defined as a resting heart rate of under 60 beats per minute that arises from the sinus node, which sets the heart rhythm.Sinus bradycardia can be normal for some people, but it may need treatment if it causes symptoms. Heart block, an abnormal type of bradycardia, may lead to serious symptoms and outcomes.
This article explains bradycardia symptoms and their causes. It discusses how bradycardia is diagnosed and how both types of heart rate problems are treated.
The hearts of adults at rest normally beat between 60 and 100 times per minute.
Verywell / JR Bee
What Is Sinus Bradycardia?
Sinus bradycardia is aslow heart ratethat involves thesinoatrial(or sinus) node, often referred to as “the heart’s natural pacemaker.” The sinus node is the part of the heart that produces electrical signals that trigger each heartbeat.
At rest, the sinus node typically generates electrical impulses for a heart rate between 60 and 100 times per minute, which is anormal sinus rhythm.
Sinus bradycardia is a heart rate between 50 to 60 beats per minute. While technically outside of the normal range, these values can be entirely normal for some people. A healthy body is very good at regulating the heart rate to support the body’s functions.
Why Is it Called Sinus Bradycardia?The term “bradycardia” is used to describe a heart rate that’s slower than typical. Sinus bradycardia is a type of slow heart rate that originates from the sinus node of your heart.
Why Is it Called Sinus Bradycardia?
The term “bradycardia” is used to describe a heart rate that’s slower than typical. Sinus bradycardia is a type of slow heart rate that originates from the sinus node of your heart.
Physiological bradycardia is a form of sinus bradycardia. Among people who have it—including healthy young people and older people in good physical condition—their resting heart rate may hover in the 40s or 50s. People also have lower heart rates when sleeping.
Slow heart rates without symptoms usually are no cause for concern. However, when the heart rate becomes too slow to pump enough blood, it needs treatment. Sinus bradycardia that produces symptoms is a sign you should seek medical care.
What to Know About Heart Rate Zones
What Are the Symptoms of Sinus Bradycardia?
If the heart rate is abnormally slow, several of the body’s organs may not function normally. A heart rate that is too slow results in various symptoms, including:
These symptoms worsen with exercise because the body’s needs increase with exertion. However, symptoms may also be present when the body is at rest if bradycardia is severe.
If bradycardia happens for an extended period of time without treatment, it can lead to complications such as:
If you have any symptoms of bradycardia, talk to your healthcare provider to determine the cause. Proper treatment can return the heart rate to normal.
The risk of dying from bradycardia is relatively low when there are no symptoms.However, a case of symptomatic bradycardia may causecardiac arrestif left untreated.
Is Sinus Bradycardia Serious?
It’s important to know the dangers because sinus bradycardia can be serious.
A slow heart rate that causes symptoms, such as chest pain or shortness of breath, requires medical attention. This can lead to life-threatening cardiac arrest. Over time, sinus bradycardia also may cause high blood pressure.
Early diagnosis and treatment are important.
What Causes Sinus Bradycardia?
Several medical conditions can cause sinus bradycardia, including:
These causes of sinus bradycardia fall into two categories:
Of the two, sinus node bradycardia is more common.
Sinus Node Bradycardia
When the sinus node produces electrical impulses at a relatively reduced rate, the heart rate becomes slow. Sinus bradycardia causes can be either transient (meaning that they don’t last long) or persistent, which is more likely to require treatment.
Heart Block
The second type of bradycardia is heart block. In contrast to sinus bradycardia, heart block is always an abnormal condition.
Heart block occurs when the heart’s electrical impulses are wholly or partially blocked as they travel from the heart’s atria (upper chambers) to theventricles—the lower chambers that pump blood out of the heart. A block between the atria and ventricles causes a change in how fast the heart beats.
Partial blocks occur when the electrical signals to the heart are delayed or intermittently stopped. A complete block happens when the signals stop entirely.
When the heart’s ventricles don’t get information from the sinus node about how fast to beat, they use information from another part of the heart between the atria and ventricles, called theAV node. This broken communication results in potentially dangerous bradycardia.
As with abnormal sinus bradycardia, a heart block can be transient or persistent.
Transient heart blockcan occur with certain conditions such as:
Persistent heart blockcan result from many conditions, including:
Risk Factors
When a Pacemaker Is Needed for a Heart Block
How Is Sinus Brachycardia Diagnosed?
An electrocardiogram (ECG) will show that a slow heart rate is present. ECG tests will help to determine whether a slow heart rate is due to sinus bradycardia or heart block.
If other tests are needed, they may include:
What Is Arrhythmia?
How Is Sinus Bradycardia Treated?
The treatment of slow heart rate depends on whether the cause is sinus bradycardia or heart block and whether it’s reversible or not.Treatment may include lifestyle changes, medication changes, or an implanted device called a pacemaker.
Reversible
In these cases, treating the underlying problem often takes care of the slow heart rate too.
If sinus bradycardia is reversible or produces no symptoms, it can often be managed through regular medical checkups.
Permanent
When partial and complete heart blocks are persistent, your healthcare provider may recommend a permanent pacemaker.
How long does it takes to feel better?How long it takes to feel better will depend on the treatment needed. You should start feeling better once medications to treat an underlying cause are working or once a temporary pacemaker is placed. If a permanent pacemaker is implanted, you can usually resume your normal activities within four weeks.
How long does it takes to feel better?
How long it takes to feel better will depend on the treatment needed. You should start feeling better once medications to treat an underlying cause are working or once a temporary pacemaker is placed. If a permanent pacemaker is implanted, you can usually resume your normal activities within four weeks.
15 Things You Can’t Do With a Pacemaker
If you have sinus bradycardia, you should see your healthcare provider annually. Call your provider if your symptoms change noticeably or if your symptoms start to affect your daily life and routine.
You should seek immediate medical care if you experience:
Summary
Bradycardia is defined as a heart rate of fewer than 60 beats per minute. The hearts of adults at rest typically beat between 60 and 100 times per minute.
A lower-than-normal heart rate poses no problem for many people unless certain symptoms appear. These symptoms include chest pain, dizziness, easy fatigue, and shortness of breath. Then it’s time to consult a physician to determine the underlying cause.
The general causes of bradycardia fall into two categories: sinus node-mediated (more common) and heart block. Treatment may involve correcting any underlying causes or implanting a pacemaker.
Frequently Asked QuestionsSome studies suggest people with anxiety disorders have a higher risk of slow heart rates.Anxiety also is shown to be a predictor of cardiovascular disease and sudden cardiac death. Contact your healthcare provider if you are concerned about stress and anxiety affecting your health.Learn MoreAnxiety DisordersIn some cases, yes, but it will depend on the cause. Slow heart rates due to infection or inflammation can be treated. Medications can be changed if they lead to slow heart rates. Keep in mind that in some cases, sinus bradycardia is actually a sign of a well-conditioned heart.Learn MoreSinus Bradycardia and Sinus Arrhythmia
Some studies suggest people with anxiety disorders have a higher risk of slow heart rates.Anxiety also is shown to be a predictor of cardiovascular disease and sudden cardiac death. Contact your healthcare provider if you are concerned about stress and anxiety affecting your health.Learn MoreAnxiety Disorders
Some studies suggest people with anxiety disorders have a higher risk of slow heart rates.Anxiety also is shown to be a predictor of cardiovascular disease and sudden cardiac death. Contact your healthcare provider if you are concerned about stress and anxiety affecting your health.
Learn MoreAnxiety Disorders
In some cases, yes, but it will depend on the cause. Slow heart rates due to infection or inflammation can be treated. Medications can be changed if they lead to slow heart rates. Keep in mind that in some cases, sinus bradycardia is actually a sign of a well-conditioned heart.Learn MoreSinus Bradycardia and Sinus Arrhythmia
In some cases, yes, but it will depend on the cause. Slow heart rates due to infection or inflammation can be treated. Medications can be changed if they lead to slow heart rates. Keep in mind that in some cases, sinus bradycardia is actually a sign of a well-conditioned heart.
Learn MoreSinus Bradycardia and Sinus Arrhythmia
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15 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.American Heart Association.Bradycardia: Slow heart rate.American Heart Association.Target heart rates chart.Cedars Sinai.Bradycardia.Dharod A, Soliman EZ, Dawood F, et al.Association of asymptomatic bradycardia with incident cardiovascular disease and mortality: The multi-ethnic study of atherosclerosis (MESA).JAMA Intern Med.2016;176(2):219-227. doi:10.1001/jamainternmed.2015.7655Johns Hopkins Medicine.Bradycardia.Breit S, Kupferberg A, Rogler G, Hasler G.Vagus nerve as modulator of the brain–gut axis in psychiatric and inflammatory disorders.Front Psychiatry. 2018;9:44. doi:10.3389/fpsyt.2018.00044Jensen PN, Gronroos NN, Chen LY, et al.Incidence of and risk factors for sick sinus syndrome in the general population.J Am Coll Cardiol.2014;64(6):531. doi:10.1016/j.jacc.2014.03.056MedlinePlus.Digitalis toxicity.Mitchell LB.Atrioventricular block. Merck Manual Professional Version.American Heart Association.Coronary artery disease.Epstein AE, DiMarco JP, Ellenbogen KA, et al.2012 ACCF/AHA/HRS focused update incorporated into the ACCF/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society.J Am Coll Cardiol. 2013;61:e6-e75. doi:10.1016/j.jacc.2012.11.007Cedars Sinai.Sinus bradycardia.Sidhu S, Marine JE.Evaluating and managing bradycardia.Trends in Cardiovascular Medicine. 2020;30(5):265-272. doi:10.1016/j.tcm.2019.07.001National Health Service UK.FAQs pacemaker implantation.Chalmers JA, Quintana DS, Abbott MJ, Kemp AH.Anxiety disorders are associated with reduced heart rate variability: A meta-analysis.Front Psychiatry. 2014 Jul 11;5:80. doi:10.3389/fpsyt.2014.00080Additional ReadingKusumoto FM, Schoenfeld MH, Barrett C, et al.2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay: executive summary.J Am Coll Cardiol. 2019;74(7):932-987. doi:10.1016/j.jacc.2018.10.043
15 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.American Heart Association.Bradycardia: Slow heart rate.American Heart Association.Target heart rates chart.Cedars Sinai.Bradycardia.Dharod A, Soliman EZ, Dawood F, et al.Association of asymptomatic bradycardia with incident cardiovascular disease and mortality: The multi-ethnic study of atherosclerosis (MESA).JAMA Intern Med.2016;176(2):219-227. doi:10.1001/jamainternmed.2015.7655Johns Hopkins Medicine.Bradycardia.Breit S, Kupferberg A, Rogler G, Hasler G.Vagus nerve as modulator of the brain–gut axis in psychiatric and inflammatory disorders.Front Psychiatry. 2018;9:44. doi:10.3389/fpsyt.2018.00044Jensen PN, Gronroos NN, Chen LY, et al.Incidence of and risk factors for sick sinus syndrome in the general population.J Am Coll Cardiol.2014;64(6):531. doi:10.1016/j.jacc.2014.03.056MedlinePlus.Digitalis toxicity.Mitchell LB.Atrioventricular block. Merck Manual Professional Version.American Heart Association.Coronary artery disease.Epstein AE, DiMarco JP, Ellenbogen KA, et al.2012 ACCF/AHA/HRS focused update incorporated into the ACCF/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society.J Am Coll Cardiol. 2013;61:e6-e75. doi:10.1016/j.jacc.2012.11.007Cedars Sinai.Sinus bradycardia.Sidhu S, Marine JE.Evaluating and managing bradycardia.Trends in Cardiovascular Medicine. 2020;30(5):265-272. doi:10.1016/j.tcm.2019.07.001National Health Service UK.FAQs pacemaker implantation.Chalmers JA, Quintana DS, Abbott MJ, Kemp AH.Anxiety disorders are associated with reduced heart rate variability: A meta-analysis.Front Psychiatry. 2014 Jul 11;5:80. doi:10.3389/fpsyt.2014.00080Additional ReadingKusumoto FM, Schoenfeld MH, Barrett C, et al.2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay: executive summary.J Am Coll Cardiol. 2019;74(7):932-987. doi:10.1016/j.jacc.2018.10.043
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
American Heart Association.Bradycardia: Slow heart rate.American Heart Association.Target heart rates chart.Cedars Sinai.Bradycardia.Dharod A, Soliman EZ, Dawood F, et al.Association of asymptomatic bradycardia with incident cardiovascular disease and mortality: The multi-ethnic study of atherosclerosis (MESA).JAMA Intern Med.2016;176(2):219-227. doi:10.1001/jamainternmed.2015.7655Johns Hopkins Medicine.Bradycardia.Breit S, Kupferberg A, Rogler G, Hasler G.Vagus nerve as modulator of the brain–gut axis in psychiatric and inflammatory disorders.Front Psychiatry. 2018;9:44. doi:10.3389/fpsyt.2018.00044Jensen PN, Gronroos NN, Chen LY, et al.Incidence of and risk factors for sick sinus syndrome in the general population.J Am Coll Cardiol.2014;64(6):531. doi:10.1016/j.jacc.2014.03.056MedlinePlus.Digitalis toxicity.Mitchell LB.Atrioventricular block. Merck Manual Professional Version.American Heart Association.Coronary artery disease.Epstein AE, DiMarco JP, Ellenbogen KA, et al.2012 ACCF/AHA/HRS focused update incorporated into the ACCF/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society.J Am Coll Cardiol. 2013;61:e6-e75. doi:10.1016/j.jacc.2012.11.007Cedars Sinai.Sinus bradycardia.Sidhu S, Marine JE.Evaluating and managing bradycardia.Trends in Cardiovascular Medicine. 2020;30(5):265-272. doi:10.1016/j.tcm.2019.07.001National Health Service UK.FAQs pacemaker implantation.Chalmers JA, Quintana DS, Abbott MJ, Kemp AH.Anxiety disorders are associated with reduced heart rate variability: A meta-analysis.Front Psychiatry. 2014 Jul 11;5:80. doi:10.3389/fpsyt.2014.00080
American Heart Association.Bradycardia: Slow heart rate.
American Heart Association.Target heart rates chart.
Cedars Sinai.Bradycardia.
Dharod A, Soliman EZ, Dawood F, et al.Association of asymptomatic bradycardia with incident cardiovascular disease and mortality: The multi-ethnic study of atherosclerosis (MESA).JAMA Intern Med.2016;176(2):219-227. doi:10.1001/jamainternmed.2015.7655
Johns Hopkins Medicine.Bradycardia.
Breit S, Kupferberg A, Rogler G, Hasler G.Vagus nerve as modulator of the brain–gut axis in psychiatric and inflammatory disorders.Front Psychiatry. 2018;9:44. doi:10.3389/fpsyt.2018.00044
Jensen PN, Gronroos NN, Chen LY, et al.Incidence of and risk factors for sick sinus syndrome in the general population.J Am Coll Cardiol.2014;64(6):531. doi:10.1016/j.jacc.2014.03.056
MedlinePlus.Digitalis toxicity.
Mitchell LB.Atrioventricular block. Merck Manual Professional Version.
American Heart Association.Coronary artery disease.
Epstein AE, DiMarco JP, Ellenbogen KA, et al.2012 ACCF/AHA/HRS focused update incorporated into the ACCF/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society.J Am Coll Cardiol. 2013;61:e6-e75. doi:10.1016/j.jacc.2012.11.007
Cedars Sinai.Sinus bradycardia.
Sidhu S, Marine JE.Evaluating and managing bradycardia.Trends in Cardiovascular Medicine. 2020;30(5):265-272. doi:10.1016/j.tcm.2019.07.001
National Health Service UK.FAQs pacemaker implantation.
Chalmers JA, Quintana DS, Abbott MJ, Kemp AH.Anxiety disorders are associated with reduced heart rate variability: A meta-analysis.Front Psychiatry. 2014 Jul 11;5:80. doi:10.3389/fpsyt.2014.00080
Kusumoto FM, Schoenfeld MH, Barrett C, et al.2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay: executive summary.J Am Coll Cardiol. 2019;74(7):932-987. doi:10.1016/j.jacc.2018.10.043
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