Related terms: arrhythmia, sinoatrial node (SA node)
Any irregularity in your heart's natural rhythm is called an arrhythmia. Almost everyone's heart skips a beat now and again, and these mild palpitations are usually harmless. But there are about 4 million Americans with recurrent arrhythmias, and these people usually need treatment for their condition.
Electrical impulses from your heart muscle (the myocardium) cause your heart to beat (contract). This electrical signal begins in the sinoatrial node, also called the SA node or the sinus node. The SA node is located at the top of the heart's upper-right chamber (the right atrium). The SA node is sometimes called the heart's "natural pacemaker." When an electrical impulse is released from the SA node, it causes the heart's upper chambers to contract.
Sick sinus syndrome is a type of arrhythmia. It is a group of signs and symptoms that tells doctors that the SA node is not working properly. The SA node usually sends electrical impulses at a certain rate, but if the SA node is not working properly, the heart may beat too fast, too slow, or both.
What causes sick sinus syndrome?
Sick sinus syndrome usually develops slowly over many years, and doctors do not always know the cause. It occurs more often in people over 50, but children may develop the condition after having open heart surgery.
What are the signs and symptoms?
Many people with sick sinus syndrome do not have symptoms, or they do not think their symptoms are serious enough for them to see a doctor.
Here are some signs and symptoms of sick sinus syndrome.
- Fainting (called syncope)
- Dizziness or lightheadedness
- Confusion that comes and goes
- Heart palpitations (the feeling that the heart has skipped a beat)
- Chest pain
- Shortness of breath
- Muscle aches
How is sick sinus syndrome diagnosed?
Sick sinus syndrome can be hard to diagnose because you may not have many of the symptoms. Your doctor will take a medical history, ask about your symptoms, and listen to your heart with a stethoscope. With the stethoscope, the doctor may be able to hear an irregular heartbeat, which can be a sign of sick sinus syndrome. Here is a list of other tests that your doctor may order.
- A standard electrocardiogram (ECG or EKG), which is the best test for diagnosing arrhythmia. This test helps doctors analyze the electrical currents of your heart and determine the type of arrhythmia you have.
- Holter monitoring, which gets a non-stop reading of your heart rate and rhythm over a 24-hour period (or longer). You wear a recording device (the Holter monitor), which is connected to small metal disks called electrodes that are placed on your chest. With certain types of monitors, you can push a "record" button to capture a rhythm when you feel symptoms. Doctors can then look at a printout of the recording to find out what causes your arrhythmia.
- Event monitors, which are devices that record problems that may not be found within a 24-hour period. The devices used for this type of test are smaller than a Holter monitor. One such device is the size of a beeper, and another is worn like a wristwatch. As with Holter monitoring, you wear the recording device. When you feel the symptoms of an arrhythmia, you can telephone a monitoring station, where a record can be made. If you cannot get to a telephone during your symptoms, you can turn on the device's memory function. Later, you can send the recorded information to a monitoring station by using a telephone. These devices also work during episodes of fainting.
- Electrophysiology studies (EPS), which are usually done in a cardiac catheterization laboratory. A long, thin tube called a catheter is inserted in an artery in your leg and guided to your heart. Electrical impulses from your heart are sent through the catheter and mapped out. This map helps doctors find out what kind of arrhythmia you have and whether it is caused by sick sinus syndrome.
How is sick sinus syndrome treated?
If you do not have any symptoms, you will not need treatment for sick sinus syndrome. If you do have symptoms, your doctor may want you to stop taking certain medicines and avoid food and drinks that make your symptoms worse.
If sick sinus syndrome is causing a slow heart rate (bradycardia), you may need to have a pacemaker implanted and you may need to take antiarrhythmic medicines.
If sick sinus syndrome is causing a fast heart rate (tachycardia), it may be treated with antiarrhythmic medicines. Sometimes a procedure called radiofrequency ablation is also recommended to treat tachycardia.
See also on this site: Arrhythmia
See also on other sites:
Sick sinus syndrome
Updated October 2012