This heart rhythm disorder causes slow, paused or irregular heartbeats. Learn the symptoms and how it's treated.
Sick sinus syndrome is a type of heart rhythm disorder. It affects the heart's natural pacemaker (sinus node), which controls the heartbeat. Sick sinus syndrome causes slow heartbeats, pauses (long periods between heartbeats) or irregular heartbeats (arrhythmias).
Sick sinus syndrome is relatively uncommon. The risk of developing it increases with age. Many people with sick sinus syndrome eventually need an implanted device called a pacemaker to keep the heart in a regular rhythm.
Sick sinus syndrome may also be called sinus node dysfunction or sinus node disease.
Most people with sick sinus syndrome have few or no symptoms. Symptoms may be mild or come and go — making them difficult to recognize at first.
Signs and symptoms of sick sinus syndrome may include:
Talk to your health care provider if you have any signs or symptoms of sick sinus syndrome. Many medical conditions can cause these problems. It's important to get a timely and accurate diagnosis.
If you have new or unexplained chest pain or think you're having a heart attack, call for emergency medical help immediately.
To understand the cause of sick sinus syndrome, it may be helpful to know how the heart typically beats.
The heart is made up of four chambers — two upper (atria) and two lower (ventricles). The rhythm of the heart is typically controlled by the sinus node, an area of specialized cells in the right upper heart chamber (right atrium).
This natural pacemaker produces electrical signals that trigger each heartbeat. From the sinus node, electrical signals travel across the atria to the ventricles, causing them to contract and pump blood to the lungs and body.
Typically, the sinus node creates a steady pace of electrical impulses. The pace changes depending on activity, emotions and other factors.
In sick sinus syndrome, the electrical signals are irregularly paced. The heartbeat can be too fast, too slow, interrupted by long pauses — or an alternating combination of these rhythm issues. Sick sinus syndrome is relatively uncommon, but the risk of developing it increases with age.
Causes of sick sinus node syndrome can include:
Features of sick sinus syndrome include:
In a typical heart rhythm, a tiny cluster of cells at the sinus node sends out an electrical signal. The signal then travels through the atria to the atrioventricular (AV) node and into the ventricles, causing them to contract and pump blood.
Sick sinus syndrome can occur at any age. It's most common in people in their 70s or older. Common heart disease risk factors might increase the risk of sick sinus syndrome. Risk factors for heart disease include:
Complications of sick sinus syndrome include:
To diagnose sick sinus syndrome, a health care provider performs a physical exam and asks about symptoms and medical history.
Symptoms of sick sinus syndrome — such as dizziness, shortness of breath and fainting — only occur when the heart is beating irregularly. You may not have symptoms at the time of the appointment.
To determine whether symptoms are related to problems with the sinus node and heart function, a health care provider may use the following tests:
This test, also called an EP study, is rarely used to screen for sick sinus syndrome. However, it may be done to check the function of the sinus node and to evaluate other electrical properties of the heart.
During an EP study, thin, flexible wires tipped with electrodes are threaded through blood vessels to different areas within the heart. Once in place, the electrodes can map the spread of electrical signals through the heart.
An electrocardiogram (ECG or EKG) is a simple test to determine how the heart is beating. Sensors (electrodes) placed on the chest record the heart's electrical signals. The signals are shown as waves on an attached computer monitor or printer.
The goals of sick sinus treatment are to reduce or eliminate symptoms and to manage any other contributing health conditions.
Treatment of sick sinus syndrome may include:
If you don't have symptoms, your health care provider may simply recommend regular health checkups to monitor your condition. Most people with symptoms need to have a procedure to implant a device to maintain a regular heartbeat (pacemaker).
Some medications, including those used to treat high blood pressure or heart disease, may interfere with sinus node function. Your health care provider will likely review the medications you take and may adjust them or prescribe different ones.
Medications may be needed to prevent or to slow down fast heartbeats.
Blood-thinners (anticoagulants), such as warfarin (Jantoven), dabigatran (Pradaxa) or others, may be prescribed if sick sinus syndrome is associated with atrial fibrillation or other irregular heart rhythms linked to stroke.
Most people with sick sinus syndrome eventually need a permanent device to control the heart rhythm (pacemaker). A pacemaker is a small, battery-powered device that's implanted under the skin near the collarbone during a minor surgical procedure. The pacemaker stimulates (paces) the heart as needed to keep it beating regularly.
If sick sinus syndrome symptoms are mild or infrequent, the decision to use a pacemaker will depend on the results of electrocardiograms (ECGs), your overall health and the risk of more-serious problems.
The type of pacemaker you need depends on the type of irregular heart rhythm you have. Types of pacemakers include:
If your heart rate is still irregular after getting a pacemaker, you may need medications or a catheter-based procedure called cardiac ablation to correct or control it. Cardiac ablation uses heat or cold energy to create tiny scars in the heart to block faulty signals and restore a regular heartbeat. It's most often done using thin, flexible tubes called catheters inserted through the veins or arteries. Less commonly, ablation is performed during cardiac surgery. A type of cardiac ablation called AV node ablation is often used to control fast heart rhythms in people with pacemakers.
In atrioventricular (AV) node ablation, a heart doctor uses radiofrequency energy to destroy the electrical connection between the upper and lower heart chambers (AV node), blocking the heart's electrical impulses. Once the AV node is destroyed, the heart doctor then implants a small medical device to maintain a heart rhythm (pacemaker).
It's important to take steps to lower the risk of heart disease. Try these heart-healthy strategies:
Call your health care provider if you have symptoms of sick sinus syndrome. You might be referred to a doctor trained in diagnosing and treating heart conditions (cardiologist).
Be prepared to answer questions about your medical history and symptoms. Write down your answers to help you remember details.
Questions your provider may ask about symptoms include:
Other questions may include the following:
Write down any questions you have for your provider. You might bring a friend or relative to write down information during the appointment.
If exercise makes your symptoms worse, avoid exercise until you see your provider.