Sick Sinus Syndrome

What is Sick Sinus Syndrome?

Sick sinus syndrome refers to heart rhythm disorders (dysrhythmias) caused by improper function of the heart’s natural pacemaker, called the sinus node. Sick sinus syndrome can cause a heart rhythm to be too fast, too slow, interrupted by long pauses or a combination of all of these. Sick sinus syndrome can be controlled with a pacemaker.

In sick sinus syndrome, the heart’s sinus node has trouble creating the electrical impulses that trigger each heartbeat. There are three types of sick sinus syndrome:

  • Sinoatrial block occurs when electrical signals move too slowly through the node, causing a slow heart rate.
  • Sinus arrest occurs when sinus node activity pauses.
  • Bradycardia-tachycardia syndrome causes the heart to alternate between abnormally fast and slow rhythms, often with long pauses between heartbeats.

If you have sick sinus syndrome causing a slow heart rate, you are at risk of fainting. Rarely, long periods of abnormally slow or fast rhythms can lead to heart failure, when the heart can’t pump enough blood to meet your body’s needs.

If you have bradycardia-tachycardia syndrome, the fast heart rhythm often indicates atrial fibrillation , which may put you at a higher risk of blood clots and stroke.

Baptist Health is known for advanced, superior care for patients with heart disease and the diagnosis, management and treatment of sick sinus syndrome. You will appreciate timely appointments and a professional, friendly atmosphere where we take time to listen to your concerns. At Baptist Health, you have access to the region’s most comprehensive, multidisciplinary team of specialists and innovative therapies, including many available only through specialized clinical trials. In every way, we work to demonstrate the utmost in excellent care to those who trust us with their health.

Sick Sinus Syndrome Signs and Symptoms

Sick sinus syndrome may cause no initial symptoms, or symptom may come and go. That’s why regular checkups are important. When they do occur, symptoms may include:

  • A fluttering or rapid heartbeat sensation, known as palpitations
  • A slow pulse
  • Chest pains
  • Dizziness
  • Fainting, or feeling faint
  • Fatigue
  • Lightheadedness
  • Shortness of breath

Sick Sinus Syndrome Diagnosis

Symptoms of sick sinus syndrome are nonspecific and can be caused by many conditions, as well as by minor issues like dehydration, a viral illness or too much caffeine. To determine if someone has sick sinus syndrome, we use advanced technology to determine if the heart is beating abnormally.

Electrocardiogram (EKG): This test measures the electrical activity of the heart and can help determine if the heart rate is fast, slow or interrupted by pauses. The heart’s electrical currents are detected by 12 to 15 electrodes that are attached to the arms, legs and chest via sticky tape.

Event monitor: This portable EKG device records the heart rate when a button is pressed. It can be worn for weeks, or until symptoms occur.

Holter monitor: This portable EKG device continuously records the heart’s rhythms and is worn for 24 to 48 hours during normal activity.

Implantable loop recorder: This small device, implanted just under the skin of the chest, is automatically triggered by an irregular heart rhythm, but can also be triggered manually. It is used for continuous, long-term monitoring of the heart's electrical activity and may be worn from months to years.

Sick Sinus Syndrome Causes

Sick sinus syndrome doesn’t have any preventable causes, but it can be triggered by calcium channel blocker or beta blocker medications used to treat high blood pressure or heart disease.

Risk Factors

Risk factors that could contribute to sick sinus syndrome include:

Age: Sick sinus syndrome develops slowly and most often affects people 70 and older, though it has been found in people of all ages. It’s typically associated with wear and tear to the heart muscle.

Diseases: In rare cases, sick sinus syndrome can be associated with conditions like muscular dystrophy and other diseases that affect the heart, especially those that can scar or damage the electrical system.

Heart attack: A heart attack can damage the heart’s electrical system.

Medications: Some drugs, such as calcium channel blockers or beta blockers used to treat high blood pressure, heart disease or other conditions, can trigger sick sinus syndrome.
Previous heart surgery: Scar tissue from a previous heart surgery can lead to sick sinus syndrome, particularly in children.


While most risk factors for sick sinus syndrome cannot be controlled, there are ways you can help prevent high blood pressure, heart disease and other conditions that can damage the heart muscle and its electrical system.

Practice good heart health: Watch what you eat, exercise and avoid smoking.

Take your medications as prescribed: If you have high blood pressure, high cholesterol or diabetes, be certain to take your prescribed medications as directed.

Get regular check-ups: Abnormal heart rhythms can be detected at a regular appointment. If you have sick sinus syndrome, the earlier you’re diagnosed and treated, the better.

Sick Sinus Syndrome Prognosis

Many people with sick sinus syndrome don’t have symptoms for years. If it’s causing a slow heart rate, pacemakers are not a cure, but they are a very effective treatment. Most patients treated with pacemakers have a positive prognosis.

Treatment and Recovery

If you have sick sinus syndrome, but don’t have symptoms, you may not need immediate treatment. Sometimes, symptoms can be managed with simple medication and dietary changes.


If sick sinus syndrome is causing a fast heart rate (tachycardia), you may be treated with antiarrhythmic medicines.

Pacemaker Implantation Surgery

Most people with sick sinus syndrome eventually need a permanent pacemaker to regulate the heartbeat. This small, battery-powered electronic device is implanted under the skin near your collarbone during a minor surgical procedure. The type of pacemaker you need depends on your irregular heart rhythm. Some people can be treated with a single- chamber pacemaker, which uses only one wire to pace one chamber of the heart, while others benefit from dual-chamber pacemakers, in which one wire paces the atrium and the other paces the ventricle.

AV Node Ablation

In this procedure, one or more catheters are threaded through blood vessels to the heart. Electrodes at the catheter tips use heat, extreme cold or radiofrequency energy to damage (ablate) the AV node and create an electrical block along the pathway.


Untreated sick sinus syndrome may lead to complications including:

Blood clots or stroke:  If you have bradycardia-tachycardia syndrome, you may be at a higher risk of developing a blood clot in your heart that may lead to a stroke. The fast heart rhythm that occurs in bradycardia-tachycardia syndrome often indicates atrial fibrillation.

Fainting: A low heart rate (bradycardia) can cause you to faint.

Heart failure: Rarely, extended periods of abnormally slow or fast heart rates can prevent the heart from pumping enough blood to meet the body’s needs — a condition called heart failure.

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