Sick Sinus Syndrome: Symptoms, Causes, and Treatment
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD. Last reviewed October 13, 2026. This content is for educational purposes and is not medical advice.
Quick Answer
Sick sinus syndrome is a disorder of the heart's natural pacemaker, the sinus node, that causes slow beats, long pauses or alternating fast and slow rhythms. [1] It may cause no symptoms at first, then dizziness, fatigue, fainting or a slow pulse. [1] It is most often caused by age-related wear and tear. Most people with symptoms need a permanent pacemaker. [2]
What the research says
Sick sinus syndrome and atrial fibrillation often go together. A meta-analysis of 35 studies and 37,550 patients found that people with sick sinus syndrome were more likely to develop new atrial fibrillation, and that pacing mostly from the right ventricle (VVI/VVIR) carried a higher risk of new atrial fibrillation than dual-chamber pacing (DDD/DDDR) (Liu et al., Int J Cardiol, 2023) [5].
Dual-chamber pacemakers cut the need for repeat surgery. Pooling six randomized trials, dual-chamber pacing reduced reoperation compared with single-chamber atrial pacing (odds ratio 0.48, 95% CI 0.36–0.63) and lowered the risk of paroxysmal atrial fibrillation (odds ratio 0.75, 95% CI 0.59–0.96), with no significant difference in mortality or stroke (Edwards et al., Health Technol Assess, 2015) [6].
Fainting can persist even after a pacemaker. In 1,415 paced patients with sick sinus syndrome, 17.5% had syncope after implantation, and those who did had higher mortality (adjusted hazard ratio 1.6, 95% CI 1.3–2.1) (Ng Kam Chuen et al., Heart, 2014) [7].
Key Facts at a Glance
Fact | Detail |
Also known as | Sinus node dysfunction, sinus node disease [1] |
What happens | The heart's natural pacemaker fires too slowly, pauses, or alternates between fast and slow [1] |
Who gets it | Most common in people in their 70s or older; can occur at any age [1] |
Most common cause | Age-related wear and tear of heart tissue |
Typical symptoms | Dizziness, fainting, fatigue, palpitations, shortness of breath [1] |
Main treatment | Permanent pacemaker for most people with symptoms [2] |
What is sick sinus syndrome?
Sick sinus syndrome is a type of heart rhythm disorder. It affects the sinus node, the heart's built-in pacemaker, which controls the heartbeat. [1] When the sinus node does not work properly, the heart may beat too slowly, pause for long periods between beats, or switch between fast and slow rhythms. [1]
The condition goes by other names as well. You may see it referred to as sinus node dysfunction or sinus node disease. [1] All three terms describe the same problem.
It is relatively uncommon, and the risk of developing it rises with age. [1] Many people with sick sinus syndrome eventually need an implanted device called a pacemaker to keep the heart in a regular rhythm. [1]
How does the sinus node normally keep the heart's rhythm?
The heart has four chambers: two upper chambers called the atria and two lower chambers called the ventricles. The rhythm of the heart is normally controlled by the sinus node, an area of specialized cells in the right upper chamber. [1]
With each beat, a tiny cluster of cells at the sinus node sends out an electrical signal. The signal travels through the atria to the atrioventricular node (AV node) and into the ventricles [1], causing them to contract and pump blood to the lungs and body.
This natural pacemaker keeps a steady pace, and the pace changes depending on activity, emotions, and other factors. In sick sinus syndrome, the signals are paced irregularly. The heartbeat can be too fast, too slow, interrupted by long pauses, or an alternating mix of these rhythm problems.
What are the symptoms of sick sinus syndrome?
Most people with sick sinus syndrome have few or no symptoms. [1] Symptoms may be mild or come and go, which makes the condition difficult to recognize at first.
Symptom | What It Looks Like |
Palpitations [1] | A sensation of rapid, fluttering heartbeats |
Chest pain or discomfort [1] | Pressure or tightness in the chest |
Confusion [1] | Trouble thinking clearly during rhythm changes |
Dizziness or lightheadedness [1] | A woozy or unsteady feeling |
Fainting or near fainting [1] | Passing out or almost passing out |
Fatigue [1] | Feeling worn out or drained |
Shortness of breath [1] | Feeling unable to get enough air |
Slower pulse (bradycardia) [1] | A resting heartbeat that is too slow |
Because these symptoms overlap with many other conditions, a timely and accurate diagnosis matters. See a healthcare provider if any of these signs appear.
Call for emergency medical help right away if you have new or unexplained chest pain [1] or think you might be having a heart attack.
What causes sick sinus syndrome?
Sick sinus syndrome has several possible causes. [1] The most common is simple age-related wear and tear of heart tissues.
Cause | How It Affects the Sinus Node |
Age-related wear and tear [1] | The heart's pacemaker tissue gradually deteriorates |
Heart surgery scarring [1] | Surgery can damage the sinus node or leave scars |
Heart disease [1] | Underlying heart conditions disrupt normal rhythm control |
Inflammatory heart diseases [1] | Inflammation affects the nodes that conduct signals |
Blood pressure medicines [1] | Calcium channel blockers and beta blockers [1] can interfere |
Arrhythmia medicines [1] | Drugs that treat irregular beats may slow the node |
Some Alzheimer's disease medications [1] | Certain memory medicines can slow the heart's pacing |
Neuromuscular diseases [1] | Conditions such as muscular dystrophy [1] can affect rhythm |
Obstructive sleep apnea [1] | Breathing pauses during sleep stress the heart's rhythm |
Rare genetic changes [1] | Inherited gene variants can alter the pacemaker cells |
What are the five ways sick sinus syndrome shows up?
Doctors describe five main features of the condition. A person may have one or several at the same time.
Sinus bradycardia. The sinus node produces a slow heartbeat. [1]
Sinus arrest. Signals from the sinus node pause, causing skipped beats. [1]
Sinoatrial exit block. Signals to the upper heart chambers are slowed or blocked, causing pauses or skipped beats. [1]
Chronotropic incompetence. The heart rate is within the regular range at rest but does not increase as much as it should during physical activity. [1]
Tachycardia-bradycardia syndrome. The heart rate alternates between unusually slow and unusually fast rhythms, often with a long pause between beats. [1]
What are the risk factors for sick sinus syndrome?
Sick sinus syndrome can occur at any age, but it is most common in people in their 70s or older. [1] Common heart disease risk factors may also increase the chance of developing it. [1]
What complications can sick sinus syndrome cause?
Left unmanaged, sick sinus syndrome can lead to serious problems. Possible complications include atrial fibrillation, a type of irregular heartbeat; heart failure; stroke; and cardiac arrest. [1]
How is sick sinus syndrome diagnosed?
Diagnosis starts with a physical exam and questions about symptoms and medical history. [2] One challenge is that symptoms such as dizziness, shortness of breath, and fainting only occur when the heart is beating irregularly [2], so you may feel perfectly fine at the appointment.
To connect the symptoms to the sinus node, a provider may order several tests.
Test | How It Works | What It Finds |
Electrocardiogram (ECG or EKG) | Sticky sensor patches (electrodes) are placed on the chest and legs [2] and connected by wires to a computer that displays or prints results | Measures the heart's electrical activity and shows how fast or slow it is beating; signal patterns reveal whether sick sinus syndrome is present |
Holter monitor | A portable ECG device worn for a day or more during normal daily activities [2] | |
Event recorder | A portable ECG device worn for up to 30 days [2] or until symptoms occur | Records the heart when a button is pressed at the moment symptoms happen [2] |
Smart watch monitors | Some personal devices, such as smart watches, offer electrocardiogram monitoring [2] | May catch irregular rhythms between appointments; ask your provider if this is an option [2] |
Implantable loop recorder | A small ECG device implanted just under the skin of the chest [2] | Provides continuous, long-term monitoring, especially useful for infrequent symptoms [2] |
Electrophysiologic (EP) testing | Thin, flexible wires tipped with electrodes are threaded through blood vessels into the heart to map electrical signals | Rarely used to screen for sick sinus syndrome, but can check sinus node function and other electrical properties [2] |
How is sick sinus syndrome treated?
The goals of treatment are to reduce or eliminate symptoms and to manage any contributing health conditions. [2] Options include regular checkups, medications, catheter procedures, and surgery to implant a pacemaker. [2]
If you have no symptoms, your provider may simply recommend regular health checkups to monitor the condition. [2] Most people with symptoms will need a procedure to implant a pacemaker that maintains a regular heartbeat. [2]
Medications
Some medicines, including those used to treat high blood pressure or heart disease, can interfere with sinus node function. Your provider will review everything you take and may adjust doses or switch to different drugs. [2]
Medications may also be needed to prevent or slow down fast heartbeats. [2]
If sick sinus syndrome is linked to atrial fibrillation or other irregular rhythms that raise stroke risk, blood thinners (anticoagulants) may be prescribed. Examples include warfarin (Jantoven) and dabigatran (Pradaxa) [2].
Pacemakers and Procedures
Most people with sick sinus syndrome eventually need a permanent device to control the heart rhythm. [2] A pacemaker is a small, battery-powered device implanted under the skin near the collarbone during a minor surgical procedure. It stimulates the heart as needed to keep it beating regularly. [3]
When symptoms are mild or infrequent, the decision to use a pacemaker depends on ECG results, overall health, and the risk of more serious problems.
The type of pacemaker depends on the rhythm problem. Most people with sick sinus syndrome benefit from dual-chamber pacemakers [2], which pace the right atrium and right ventricle separately.
Pacemaker Type | How It Works | Best For |
Single chamber | Carries electrical signals to the right lower chamber (ventricle) [2] | Simple pacing needs |
Dual chamber | Paces the right ventricle and right atrium separately [2] | Most people with sick sinus syndrome benefit most from this type [2] |
Biventricular | Stimulates both lower chambers (right and left ventricles) so the heart beats more efficiently; also called cardiac resynchronization therapy [2] |
If the heart rate is still irregular after a pacemaker is in place, medications or a catheter-based procedure called cardiac ablation can help. Ablation uses heat or cold energy to create tiny scars in the heart that block faulty signals [2] and restore a regular heartbeat. Thin, flexible tubes called catheters are inserted through veins or arteries [2], usually at the groin.
A specific form called AV node ablation is often used to control fast heart rhythms in people with pacemakers. [2] Radiofrequency energy destroys the electrical connection between the upper and lower chambers (the AV node), after which a pacemaker is implanted to maintain the rhythm.
How can you protect your heart with sick sinus syndrome?
Lowering your overall heart disease risk matters. Try these heart-healthy strategies.
Step | How It Helps |
Eat a healthy diet | Generous portions of nonstarchy vegetables, fruits, and whole grains [2]; modest portions of fish, lean meats, poultry, and dairy |
Exercise and maintain a healthy weight | Being overweight raises heart disease risk; aim for at least 30 minutes of moderate activity daily unless told otherwise [2] |
Control blood pressure and cholesterol | Lifestyle changes plus medications taken as prescribed [2] |
Don't smoke | Quitting programs are available if you cannot quit on your own [2] |
Limit or avoid alcohol | Drink in moderation if at all; some conditions call for avoiding it entirely [2] |
Don't use illegal drugs | Programs are available to help with quitting [2] |
Control stress | Exercise, mindfulness, and support groups all help [2] |
Keep scheduled checkups | Regular exams let you report new signs or symptoms early [2] |
How should you prepare for a sick sinus syndrome appointment?
If you have symptoms of sick sinus syndrome, call your healthcare provider. You may be referred to a cardiologist, a doctor trained in diagnosing and treating heart conditions. [2]
If exercise makes your symptoms worse, avoid exercise until you see your provider. [2]
Expect questions about your symptoms, such as whether you feel lightheaded or dizzy, whether you have fainted, whether you have rapid or fluttering heartbeats, whether you feel chest pressure or pain, whether activity worsens symptoms, and how often and how long symptoms last. [2]
Your provider will also ask about other diagnoses such as high blood pressure, high cholesterol, diabetes, or a heart condition. Write down all medicines you take with dosages, including over-the-counter drugs, herbal remedies, and supplements, and note any recent medicine changes. [2]
Bringing a friend or relative who can write down information during the appointment can be very helpful. Write down your own questions beforehand too. [2]
Conclusion and Next Steps
Sick sinus syndrome is a problem of the heart's own pacemaker, and it often stays quiet until its symptoms begin to interfere with daily life. Because dizziness, fainting, and fatigue have many possible causes, getting an accurate diagnosis is the key first step.
Monitoring, medication review, and blood thinners play a role, but the cornerstone of treatment for most people with symptoms is a permanent pacemaker. Modern pacemakers are small, implanted through minor surgery, and available in single-chamber, dual-chamber, and biventricular designs matched to the person's rhythm problem.
Take the next step: If you or someone you know has unexplained fainting, a racing or fluttering chest, or extreme tiredness, especially later in life, bring it up with a healthcare provider.
Frequently Asked Questions
What does sick sinus syndrome feel like?
Many people have no symptoms at all. When symptoms occur, they may include fluttering heartbeats, dizziness, fatigue, shortness of breath, chest discomfort, confusion, fainting, or a slower-than-normal pulse, and they often come and go.
Is sick sinus syndrome the same as sinus node dysfunction?
Yes. Sick sinus syndrome, sinus node dysfunction, and sinus node disease are three names for the same condition affecting the heart's natural pacemaker.
Can sick sinus syndrome be cured?
There is no cure for the underlying pacemaker problem, but it can be managed. Most people with symptoms receive a pacemaker that restores and maintains a regular heartbeat.
Who is most likely to get sick sinus syndrome?
Sick sinus syndrome can occur at any age but is most common in people in their 70s or older. Risk also rises with high blood pressure, high cholesterol, excess weight, and lack of exercise.
What does a pacemaker do for sick sinus syndrome?
A pacemaker is a small battery-powered device implanted under the skin near the collarbone. It monitors the heart and sends electrical signals as needed to keep the beat regular.
Is sick sinus syndrome dangerous?
It can usually be managed well, often with a pacemaker. Left untreated, it can lead to problems such as atrial fibrillation, heart failure, stroke or cardiac arrest. Call 911 for fainting, new chest pain or severe shortness of breath.
How is sick sinus syndrome diagnosed?
An electrocardiogram (ECG) is the main test. Because symptoms come and go, a provider may also use a Holter monitor, an event recorder or a small implanted loop recorder to catch the rhythm problem.
Can medicines cause sick sinus syndrome symptoms?
Yes. Some blood pressure medicines, such as beta blockers and calcium channel blockers, and some heart rhythm or Alzheimer's medicines can slow the sinus node. Do not stop any medicine on your own; ask your provider to review them.
Can I exercise with sick sinus syndrome?
If exercise makes your symptoms worse, avoid it until you see your provider. After diagnosis and treatment, your care team can tell you what kind of activity is safe for you.
Do people with sick sinus syndrome need blood thinners?
Some do. If the condition comes with atrial fibrillation or other rhythms that raise stroke risk, a provider may prescribe a blood thinner (anticoagulant).
Trusted External Resources
Related Reading
Bradycardia: Slow Heart Rate, Symptoms, Causes, and Treatment explains a slow heart rate, its causes and when it needs treatment.
Permanent Pacemakers: A Complete Guide to Heart Rhythm Management explains how pacemakers are placed and how they control heart rhythm.
Holter Monitor: What It Detects, How It Works and Results describes the wearable ECG used to catch rhythm problems that come and go.
Atrial Fibrillation (AFib): Symptoms, Causes & Treatment Guide explains a common irregular rhythm that can occur with sick sinus syndrome.
References
Mayo Clinic Staff. Sick sinus syndrome - Symptoms & causes. Mayo Clinic. April 30, 2022. https://www.mayoclinic.org/diseases-conditions/sick-sinus-syndrome/symptoms-causes/syc-20377554
Mayo Clinic Staff. Sick sinus syndrome - Diagnosis & treatment. Mayo Clinic. April 30, 2022. https://www.mayoclinic.org/diseases-conditions/sick-sinus-syndrome/diagnosis-treatment/drc-20377560
National Heart, Lung, and Blood Institute. Pacemakers: What Are Pacemakers?. National Heart, Lung, and Blood Institute. Last updated March 24, 2022. https://www.nhlbi.nih.gov/health/pacemakers
American Heart Association. Ablation for Arrhythmias. American Heart Association. Last reviewed October 24, 2024. https://www.heart.org/en/health-topics/arrhythmia/prevention--treatment-of-arrhythmia/ablation-for-arrhythmias
Liu Y, Zheng Y, Tse G, et al. Association between sick sinus syndrome and atrial fibrillation: A systematic review and meta-analysis. Int J Cardiol. 2023;381:20-36. PMID 37023861. https://doi.org/10.1016/j.ijcard.2023.03.066
Edwards SJ, Karner C, Trevor N, Wakefield V, Salih F. Dual-chamber pacemakers for treating symptomatic bradycardia due to sick sinus syndrome without atrioventricular block: a systematic review and economic evaluation. Health Technol Assess. 2015;19(65):1-210. PMID 26293406. https://doi.org/10.3310/hta19650
Ng Kam Chuen MJ, Kirkfeldt RE, Andersen HR, Nielsen JC. Syncope in paced patients with sick sinus syndrome from the DANPACE trial: incidence, predictors and prognostic implication. Heart. 2014;100(11):842-847. PMID 24711481. https://doi.org/10.1136/heartjnl-2013-304976
Medical disclaimer
The information provided in this article is for educational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
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