Sick Sinus Syndrome | Heart and Vascular

Heart and Vascular Care

Sick Sinus Syndrome

You can rely on our leading heart specialists to create a personalized plan for your sick sinus syndrome care, based on the latest treatment available.

Medically reviewed by M. Bilal Munir, M.D. on May 25, 2023.

Older woman and man talking to a health care provider in a clinic room.

What Is Sick Sinus Syndrome?

The heart has a natural pacemaker that regulates its heartbeat called the sinus node. When this sinus node does not function correctly, the condition is known as sick sinus syndrome, a type of heart arrhythmia. Sick sinus syndrome may also be called sinus node dysfunction, sinus node disease or sinus bradycardia.

Sometimes this condition occurs in patients with other fast rhythms (tachycardia). In those cases, your heartbeat may become too slow (bradycardia), too fast (tachycardia) or alternate between the two (bradycardia-tachycardia). Your heart’s sinus node also may suddenly pause or stop (sinus pause or sinus arrest) for more than 2 to 3 seconds.

Sick sinus syndrome is uncommon and is often found in people aged 50 and older, with increasing prevalence as people age. Most people don’t have symptoms, while some need an implanted pacemaker to restore their normal heart rhythm.


Symptoms of Sick Sinus Syndrome

Most people with sick sinus syndrome report few or no symptoms. Some people report symptoms that come and go. A physician or other health care provider may also notice an irregular heartbeat during your examination for another health reason.

Common Symptoms

It’s important to talk to your physician if you experience any sick sinus syndrome symptoms, which can include: 

  • Alternating fast (tachycardia) and slow (bradycardia) heartbeat  
  • Dizziness or feeling lightheaded 
  • Fainting or near-fainting 
  • Confusion 
  • Fluttering sensation in the chest 
  • Heart palpitations 
  • Tiredness or weakness  

Emergency Symptoms

In some cases, sick sinus syndrome or any irregular heartbeat can be dangerous and require immediate medical attention.

Call 911 if you experience heart attack symptoms such as: 

  • Chest pain or pressure 
  • Cold sweats, nausea or lightheadedness 
  • Collapse and sudden cardiac arrest 
  • Discomfort in your arms, back, stomach, neck or jaw 
  • Heart palpitations 
  • Shortness of breath 

Causes of Sick Sinus Syndrome

Sick sinus syndrome, a type of irregular heartbeat, can happen for many reasons. Sometimes, your physician may not be able to find the cause. Any medical condition that can cause heart damage can damage the sinus node, including:

Atrial Fibrillation

Atrial fibrillation is a common arrhythmia in which the upper chambers of heart quiver. Long-term atrial fibrillation can sometimes change how your sinus node works, resulting in dysfunction.

Connective Tissue Diseases

Connective tissue diseases are autoimmune disorders that affect the skin, joints and internal organs. Some are known to affect your heart rhythm.

Coronary Artery Disease (CAD)

When the arteries that carry blood to the heart become hardened and narrowed due to plaque buildup, it is called CAD.

Genetic Mutations

Genetic mutations are a rare problem with your genes. Mutations in the HCN4 gene can cause sick sinus syndrome. The disease is not considered hereditary (passed down in families).

Heart Attack or Heart Failure

A heart attack (blockage of coronary arteries) or heart failure can damage to the heart muscle, including the sinus node cells.


Hypertension (high blood pressure) is a condition in which your blood pressure is higher than the normal range. It can contribute to atrial fibrillation or CAD.

Injury or Breakdown of Sinus Node

The heart’s sinus node can be affected by heart surgery or aging as the heart rate slows with age due to lower sinus node function.


Medicines used to lower your blood pressure (channel blockers), slow (beta-blockers) or regulate the heart rate (antiarrhythmics) may interfere with sinus node function.

Muscular Dystrophy (MD)

MD can cause progressive weakness and degeneration of your muscles. In some types of MD, diseases of the lungs and heart can occur.

Severe Hypothyroidism

Hypothyroidism (an underactive thyroid) happens when your thyroid gland doesn’t make enough thyroid hormones. This condition can slow down many of your body’s functions, including your heartbeat.


Sick Sinus Syndrome Risk Factors

Changes in heartbeat are expected during sleep, physical activity and moments of stress. However, you should talk to your physician if you experience an irregular heartbeat, as it may be a serious problem.

In addition to the causes of sick sinus syndrome, you are more likely to get sick sinus syndrome if you:

Carry Excess Body Weight

As with an inactive lifestyle, excess body weight is associated with heart disease. Among its many effects, it can lead to inflammation and stress on the heart muscle.

Don’t Exercise Regularly

Regular physical activity helps to promote healthy heart function. Sedentary lifestyles can impair blood flow to the heart and are associated with many heart-related diseases, including sick sinus syndrome.

Use Tobacco Products

Tobacco use significantly contributes to cardiovascular disease. Chemicals in tobacco can cause narrow and blocked arteries and blood vessels and increase the risk of blood clots.


Diagnosing Sick Sinus Syndrome

Expect your physician to do a physical exam and ask questions about your medical history and symptoms. They may rule out other conditions first, like electrolyte imbalance, hypothyroidism, or sleep apnea.

Keep track of when and how often your symptoms occur, and bring that information to your appointment. Your observations can help your physician diagnose and treat sick sinus syndrome.

Your physician may order common tests to confirm an irregular heartbeat and any conditions that can cause sick sinus syndrome.

You may undergo: 

  • Heart rhythm monitoring (Holter monitor) to record your heart’s activity over a period of time.  
  • Blood tests to check your electrolyte levels or look for genetic issues. 
  • Electrocardiogram (ECG or EKG) to detect your heart’s electrical activity and measure the time and duration of its activity. 
  • Electrophysiology testing (EP study), which shows the electrical activity in your heart through electrodes placed in the heart. 
  • Stress tests, which are medically-supervised exercise tests performed on a treadmill or stationary bike. Your physician may use these tests to check if physical activity triggers or worsens an irregular heartbeat and also to see if you have an appropriate response to stress. 

Treatments for Sick Sinus Syndrome

Treatment may not be necessary if you do not have any symptoms. Your physician will review your current medications during an initial exam to make sure they won’t worsen your condition.

Sick sinus syndrome is most often treated with a permanent pacemaker. There may also be alternative treatment options using medications and other procedures. Your physician will recommend treatments based on the type and severity of your condition.


Your physician may recommend medications to prevent or to slow down a fast heartbeat (tachycardia). Blood-thinners could be prescribed if your sick sinus syndrome is associated with atrial fibrillation, which puts you at risk for a stroke.

Lifestyle Changes

Adopting a heart-healthy lifestyle is the most common way to lower your risk of more severe health complications.

These changes include: 

  • Controlling cholesterol levels
  • Eating a heart healthy diet
  • Exercising regularly
  • Limiting or avoiding alcohol consumption
  • Losing excess weight
  • Managing stress

Quitting smoking or other tobacco use.

Learn about our heart health classes


  • Pacemaker: Most people with severe sick sinus syndrome symptoms have a permanent pacemaker surgically implanted. This device delivers small electrical pulses to the heart to restore your regular heartbeat. It is placed under the skin, typically below the collarbone.
  • Catheter Ablation: This surgical treatment creates tiny scars in the heart. Creating this scar tissue blocks irregular electrical signals and restores a typical heartbeat.

Who does it affect?

50+Age of people commonly diagnosed with sick sinus syndrome

Source: MedlinePlus: Sick Sinus Syndrome

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