Sick Sinus Syndrome
The sinoatrial node (also called the sinus node) is called your heart's natural pacemaker. When its ability to function normally is disturbed and no cause can be identified, the condition is known as sick sinus syndrome.
One variation of sick sinus syndrome is a pattern of slow heart beats followed by a period of very rapid heart beats. This can cause atrial flutter and fibrillation.
Symptoms
While some people with certain types of sick sinus syndrome have no symptoms, others with sick sinus syndrome may have:
- A low heart rate
- Fatigue
- Heart palpitations
- Lethargy
Causes and Risk Factors
No cause for sick sinus syndrome has been identified. It may be a defect in the sinoatrial node. However, many patients have features that suggest there may also be abnormalities of the atrioventricular nodal as well.
Diagnosis
Your doctor will note your medical and family history and your symptoms before doing a physical examination.
A slow pulse, especially if it is irregular, may be a sign of sick sinus syndrome. In this case, your doctor may order a 24-hour Holter Monitor test to record your heart's electrical activity over a 24-hour period as you go about your regular activities.
Another test your doctor may order is tilt table testing. This is usually recommended for people who have a history of fainting for an unknown reason and don't have any structural heart disease. During this test your blood pressure and heart rate are continuously monitored while you lay on a mechanized table that is tilted at a 60° to 80° angle for 15 to 20 minutes at each angle. If your blood pressure doesn't increase, you will be given a drug intravenously to raise your heart rate by about 20 beats a minute and the test is repeated.
Treatment
If sick sinus syndrome is causing you symptoms, you may need to have an artificial pacemaker implanted to regulate your heart rhythms.
Drugs to prevent
arrhythmias (irregular heart rhythms) may also be prescribed.
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