Sick sinus syndrome is the inability of the heart’s natural pacemaker (sinus node) to create a heart rate that’s appropriate for the body’s needs. It causes irregular heart rhythms (arrhythmias). Sick sinus syndrome is also known as sinus node dysfunction or sinus node disease.
The sinus node is an area of specialized cells in the upper right chamber of the heart. This area controls your heartbeat. Normally, the sinus node creates a steady pace of electrical impulses. The pace changes depending on your activity, emotions, rest and other factors.
In sick sinus syndrome, the electrical signals are abnormally paced. Your heartbeat can be too fast, too slow, interrupted by long pauses — or an alternating combination of these rhythm problems. Sick sinus syndrome is relatively uncommon, but the risk of developing it increases with age.
Many people with sick sinus syndrome eventually need a pacemaker to keep the heart in a regular rhythm.
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:
- Dizziness or lightheadedness
- Fainting or near fainting
- Shortness of breath
- Chest pain or discomfort
- Slower than normal pulse (bradycardia)
- A sensation of rapid, fluttering heartbeats (palpitations)
The rhythm of your heart is normally controlled by the sinus node, an area of specialized cells in the right upper heart chamber (atrium). If you have sick sinus syndrome, your sinus node isn’t working properly, causing your heart rate to be too slow (bradycardia), too fast (tachycardia) or irregular.
Problems of the sinus node include the following:
- Sinus bradycardia. The sinus node produces an electrical charge at a slower rate than normal.
- Sinus arrest. Signals from the sinus node pause, causing skipped beats.
- Sinoatrial exit block. Signals to the upper heart chambers are slowed or blocked, causing a pause or skipped beats.
- Chronotropic incompetence. The heart rate is normal at rest, but doesn’t increase with physical activity.
- Bradycardia-tachycardia syndrome. The heart rate alternates between abnormally slow and fast rhythms, usually with a long pause (asystole) between heartbeats.
Sick sinus syndrome can occur at any age, but it’s most common in people in their 70’s or older. Common heart disease risk factors may increase the risk of sick sinus syndrome:
- High blood pressure
- High cholesterol
- Excess body weight
- Lack of exercise
When your heart’s natural pacemaker isn’t working properly, your heart can’t work as well as it should. This can lead to:
- Atrial fibrillation, a chaotic rhythm of the upper chambers of the heart
- Heart failure
- Cardiac arrest
Symptoms of sick sinus syndrome — such as dizziness, shortness of breath and fainting — only occur when the heart is beating abnormally.
To determine if your symptoms are related to problems with the sinus node and heart function, I may use the following tests:
- Electrocardiogram (ECG). During this test, sensors (electrodes) are attached to your chest and legs to create a record of the electrical signals traveling through your heart. The test might show patterns that indicate sick sinus syndrome, including a fast heart rate, slow heart rate or long pause in the heartbeat after a fast heart rate. We perform this test on you every year at the time of your physical.
- Holter monitor. This portable ECG device is carried in your pocket or in a pouch on a belt or shoulder strap. It automatically records your heart’s activity for 24 to 72 hours, which provides your doctor with an extended look at your heart rhythms. You may be asked to keep a diary of symptoms.
- Event recorder. This portable ECG, which may be worn up to a month, enables your doctor to correlate symptoms and heart rhythm. When you feel symptoms, you push a button, and a brief ECG recording is saved.
- Other telemetry monitors. ZIO patch. Some personal devices, such as smart watches, offer electrocardiogram monitoring.
- Implantable loop recorder. This small ECG device is implanted just under the skin of your chest and is used for continuous, long-term monitoring of your heart’s electrical activity, particularly if you have infrequent symptoms.
The primary treatment goals are to reduce or eliminate symptoms and to manage and treat any other health conditions that may be contributing to sick sinus syndrome.
If you don’t have symptoms, I may recommend regularly scheduled exams to monitor your condition. For most people with symptoms, the treatment is an implanted electronic pacemaker. If your symptoms are mild or infrequent, the decision to use a pacemaker will depend on results of ECG exams, your overall health, and the risk of more-serious problems.
Lifestyle and Behavioral Changes
You many not necessarily prevent sick sinus syndrome, but you can take steps to keep your heart as healthy as possible and lower your risk of cardiovascular disease:
- Exercise and eat a healthy diet. Live a heart-healthy lifestyle by exercising regularly. Eat a diet with generous portions of nonstarchy vegetables, fruit and whole grains and modest portions of fish, lean meats, poultry and dairy.
- Maintain a healthy weight. Being overweight increases your risk of developing heart disease. Ask us what your goal weight should be.
- Keep blood pressure and cholesterol under control. Make lifestyle changes and take medications as prescribed to correct high blood pressure (hypertension) or high cholesterol.
- Don’t smoke. If you smoke and can’t quit on your own, talk to me about strategies or programs to help you break a smoking habit.
- If you drink, do so in moderation.
- Don’t use illegal drugs.
- Control stress. Avoid unnecessary stress and learn coping techniques to handle normal stress in a healthy way.
- Go to scheduled checkups. Have regular physical exams and report any signs or symptoms to me, Dr. Guy.