Bradyarrhythmia: Symptoms, Causes, and Treatment Explained
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick answer
Bradyarrhythmia is a heart rate below 60 beats per minute caused by an irregular heart rhythm; a normal adult resting rate is 60 to 100 [1] [3]. Causes include heart disease, aging of the electrical system, medications and an underactive thyroid [1]. It can cause dizziness, fainting and fatigue [1]. Treatment addresses the underlying condition or uses a pacemaker to keep a steady rate [1].
What the research says
According to PubMed:
Hypertrophic cardiomyopathy raised the risk of bradyarrhythmia and pacemaker implantation. In a Taiwanese nationwide cohort of 15,266 people (7,633 with HCM and 7,633 matched controls) followed for about 4 years, HCM was associated with higher risks of bradyarrhythmia (adjusted HR 2.15) and permanent pacemaker implantation (adjusted HR 6.58). (Yang et al., Clin Cardiol, 2026 [5]).
Leadless pacemakers had high success in high-risk patients. In a multicenter registry of 138 patients with bradyarrhythmia who were unsuitable for transvenous pacing, implantation was successful in 98%, acute complications occurred in 2.9%, and the 1-year cumulative complication rate was 4.7%. (Katz et al., Pacing Clin Electrophysiol, 2026 [6]).
Empiric pacing reduced recurrent fainting in selected patients. A meta-analysis of 6 studies (n = 601) of patients with unexplained syncope and bifascicular block found empiric pacemaker implantation cut syncope recurrence (RR 0.48) without significantly increasing device complications or cardiovascular death. (Fahim et al., Int J Cardiol Heart Vasc, 2026 [7]).
Study details are from PubMed abstracts.
What is bradyarrhythmia?
A bradyarrhythmia is a heart rate that's slower than typical because of an irregular heart rhythm. People with bradyarrhythmia have resting heart rates below 60 beats per minute [1]. For most adults, a resting heart rate of 60 to 100 beats per minute is considered normal [1] [3].
Sometimes, healthy people have naturally slow heart rates. But people with bradyarrhythmia have a heart rate that's slow because of a medical condition, heart disease, or defect that affects the heart's rhythm [1].
What's the difference between bradyarrhythmia and bradycardia?
Both terms mean having a slower than average heart rate. Bradycardia describes a resting heart rate below 60 beats per minute. Bradyarrhythmia describes a slow heart rate caused by an irregular heartbeat (arrhythmia) [1].
Healthy young people and athletes often have resting heart rates below 60 beats per minute. For them, bradycardia doesn't indicate disease — in fact, the slow heart rate is a sign of their fitness and well-exercised heart [1] [3]. It's also normal for your heart rate to drop below 60 beats per minute when you're sleeping [1] [2].
What are the types of bradyarrhythmias?
There are several different types of bradyarrhythmias. Each type has its own causes, but they all result in a slower-than-typical heart rate.
Type | What happens |
Sinus node dysfunction (sick sinus syndrome) | |
Heart block | Something gets in the way of the heart's electrical signals, stopping impulses from traveling as they should — resulting in a slow heart rate or skipped heartbeats [1] |
Bradycardia/tachycardia syndrome |
What are the symptoms?
When the heart pumps too slowly, you may not get enough blood and oxygen to your brain. Symptoms of bradyarrhythmia may include dizziness, fainting (syncope), fatigue, shortness of breath, and weakness [1] [2].
What causes bradyarrhythmia?
Most arrhythmias, including bradyarrhythmia, result from heart disease or damage to the heart. Some causes include age-related changes in the heart's electrical system, coronary artery disease, heart defects, heart medications (such as beta-blockers), metabolic imbalances (like an underactive thyroid), and trauma or injury to the heart (such as from a heart attack) [1].
How is bradyarrhythmia diagnosed?
Your healthcare provider will perform a thorough physical exam and ask about any symptoms you're experiencing. To diagnose a heart arrhythmia accurately, your provider will measure and track your heart rate. Diagnostic tests may include an electrocardiography (EKG) — also called an ECG — which records the heart's electrical impulses [1] [3].
Your heart may not produce an abnormal rhythm while you're in the doctor's office. To help diagnose an arrhythmia, you may need to wear a portable (ambulatory) monitor, such as a Holter monitor, for 24 to 48 hours [1] [3].
An exercise stress test raises your heart rate while you walk on a treadmill and helps identify abnormal heart rhythms [1]. Echocardiography (an echocardiogram) provides pictures of your heart's valves and chambers as they pump blood [1]. And an electrophysiologic testing (electrophysiology study) provides detailed information about how your heart's electrical system is working [1] [3].
Test | What it does |
Electrocardiography (EKG/ECG) | Records the heart's electrical impulses |
Portable ECG device (ambulatory/Holter monitor) | Worn for 24 to 48 hours to catch rhythms that don't appear in the office |
Exercise stress test | Raises the heart rate on a treadmill to identify abnormal rhythms |
Echocardiography | Pictures the heart's valves and chambers as they pump blood |
Electrophysiologic testing | Gives detailed information about how the heart's electrical system works |
How is bradyarrhythmia treated?
In some cases, an underlying medical condition leads to bradyarrhythmia. Treating an underactive thyroid, for example, can help improve your slow heart rate [1].
When bradyarrhythmia results from changes in the heart's electrical system, your provider may recommend inserting a pacemaker. This electronic device generates electrical impulses to help you maintain a steady, healthy heart rate [1] [3].
What is the outlook?
Left untreated, bradyarrhythmia can lead to serious health problems and can lead to dizziness and syncope. Getting the right treatment can restore your heart's normal rhythm and reduce your risk of complications [1].
How can you prevent bradyarrhythmia?
One preventive step is treating underlying health conditions, like hypothyroidism. You can also lower your risk of bradyarrhythmia by taking good care of your heart: eating a heart-healthy diet, limiting alcohol intake, maintaining a healthy weight, staying physically active, and quitting smoking and tobacco products [1].
When should you call the doctor?
Emergency: Call 911 or your local emergency number right away if you have chest pain, trouble breathing or fainting. Call your healthcare provider if you have dizziness, lightheadedness or severe fatigue [1].
Conclusion
Bradyarrhythmia is more than a low number on a fitness tracker — it's a slow heart rate caused by an irregular rhythm, and it often means your brain isn't getting enough blood and oxygen. Dizziness, fainting, fatigue, shortness of breath, and weakness are the classic warning signs. The causes run from age-related changes in the heart's electrical system and coronary artery disease to underactive thyroid and beta-blocker medications. Diagnosis relies on an EKG, sometimes a 24–48 hour Holter monitor, stress testing, echocardiography, or an electrophysiology study. The good news: treating the underlying condition or fitting a pacemaker can restore a normal rhythm and cut the risk of complications. If your heart rate runs slow and you feel dizzy or faint, don't wait it out — see a healthcare provider promptly.
Concerned about a slow or irregular heartbeat? Get clear, plain-language answers. Explore more trusted heart health guides at Rinnit.com — your everyday companion for understanding conditions, treatments, and staying healthy.
Frequently asked questions
What is bradyarrhythmia?
A bradyarrhythmia is a heart rate that's slower than typical because of an irregular heart rhythm (arrhythmia). People with bradyarrhythmia have resting heart rates below 60 beats per minute — for most adults, 60 to 100 beats per minute is normal.
What's the difference between bradyarrhythmia and bradycardia?
Both mean a slower than average heart rate. Bradycardia is a resting heart rate below 60 bpm. Bradyarrhythmia is a slow heart rate caused by an irregular heartbeat.
Can a slow heart rate be normal?
Yes. Healthy young people and athletes often have resting heart rates below 60 bpm, and for them it's a sign of fitness, not disease. It's also normal for your heart rate to drop below 60 while sleeping.
What are the symptoms?
Dizziness, fainting (syncope), fatigue, shortness of breath, and weakness — caused when the heart pumps too slowly to deliver enough blood and oxygen to the brain.
What causes bradyarrhythmia?
Most cases result from heart disease or damage to the heart. Other causes include age-related changes in the heart's electrical system, coronary artery disease, heart defects, heart medications like beta-blockers, metabolic imbalances such as an underactive thyroid, and heart trauma (such as from a heart attack).
What are the types?
Sinus node dysfunction (sick sinus syndrome), where the heart's natural pacemaker becomes underactive; heart block, where electrical signals are blocked from traveling properly; and bradycardia/tachycardia syndrome, with alternating slow and fast rates (atrial fibrillation is one example).
What is the sinus node?
The sinus (or sinoatrial) node is the heart's natural pacemaker — part of the heart's electrical system that sends the electrical impulse triggering each heartbeat.
How is it diagnosed?
With a physical exam and tests such as an EKG (which records the heart's electrical impulses), a 24–48 hour Holter monitor, an exercise stress test, an echocardiogram, or an electrophysiology study.
What is a Holter monitor?
A portable (ambulatory) ECG monitor you wear for 24 to 48 hours. It's used because your heart may not show an abnormal rhythm while you're in the doctor's office.
How is bradyarrhythmia treated?
If an underlying condition causes it — like an underactive thyroid — treating that condition can improve the slow heart rate. When it results from changes in the heart's electrical system, a pacemaker may be inserted to generate electrical impulses and maintain a steady, healthy heart rate.
What does a pacemaker do?
It's an electronic device that generates electrical impulses to help you maintain a steady, healthy heart rate.
What is the outlook without treatment?
Left untreated, bradyarrhythmia can lead to serious health problems, dizziness, and syncope (fainting).
Can it be prevented?
Treating underlying conditions like hypothyroidism is one step. You can also lower your risk with good heart care: a heart-healthy diet, limiting alcohol, maintaining a healthy weight, staying active, and quitting smoking.
When should I call the doctor?
Call 911 right away for chest pain, trouble breathing or fainting. Call your doctor for dizziness, lightheadedness or severe fatigue.
What questions should I ask my doctor?
How do I know if my heart rate is too slow? Is my heart rate low enough to cause health problems? Do I need medication to control my arrhythmia? Will I need a pacemaker to restore a normal heart rhythm?
Related reading
This article is for general informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about any heart-related concern, and seek immediate care for chest pain, difficulty breathing, or fainting.
References
Cleveland Clinic. Bradyarrhythmia: Symptoms, Causes and Treatment. Cleveland Clinic. Updated June 20, 2022. https://my.clevelandclinic.org/health/diseases/23349-bradyarrhythmia
American Heart Association. Bradycardia: Slow Heart Rate. American Heart Association. Reviewed September 25, 2024. https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/bradycardia--slow-heart-rate
Mitchell LB. Overview of Abnormal Heart Rhythms. Merck Manual Consumer Version. Updated February 2026. https://www.merckmanuals.com/home/heart-and-blood-vessel-disorders/abnormal-heart-rhythms/overview-of-abnormal-heart-rhythms
Mitchell LB. Sinus Node Dysfunction. Merck Manual Consumer Version. Updated October 2024. https://www.merckmanuals.com/home/heart-and-blood-vessel-disorders/abnormal-heart-rhythms/sinus-node-dysfunction
Yang TA, et al. Hypertrophic cardiomyopathy and the risk of bradyarrhythmia and permanent pacemaker implantation: a nationwide cohort study. Clinical Cardiology. 2026;49(8):e70454. PMID 42643019. https://doi.org/10.1002/clc.70454
Katz M, et al. Leadless pacemaker implantation in high-risk patients: real-world outcomes from a multicenter Israeli registry. Pacing and Clinical Electrophysiology. 2026. PMID 42389970. https://doi.org/10.1111/pace.70333
Fahim M, et al. Empiric pacing in unexplained syncope and bifascicular block: a systematic review and meta-analysis. International Journal of Cardiology. Heart & Vasculature. 2026;63:101894. PMID 41783543. https://doi.org/10.1016/j.ijcha.2026.101894
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