Sick sinus syndrome (SSS) is not a relatively common heart rhythm disorder. SSS isn’t a specific disease, but rather a group of symptoms or signs that indicate the sinus node, the heart’s natural pacemaker, isn’t functioning properly. An individual with SSS may have a heart rhythm that is beating too slow (bradycardia), too fast (tachycardia), or a rhythm that alternates between the slow and fast (bradycardia-tachycardia).
What is Sick Sinus Syndrome?
The sinus node is a group of cells in the atria, the upper chamber of the heart, that generates electrical signals that regulate the rhythm and pace of the heartbeat. Normally, the sinus node creates a steady regular pattern of signals. With SSS, this pattern is irregular. Sick sinus syndrome may be caused by defects in the heart itself, or it can be affected by other factors outside the heart.
Symptoms of Sick Sinus Syndrome
Most people with sick sinus syndrome have no or a few symptoms. Other people have sporadic symptoms, such as:
- Fainting (syncope)
- Weakness
- Chest pain (angina)
- Confusion
- Slower pulse rate (bradycardia)
- Always feeling tired (fatigue)
- Shortness of breath (dyspnea)
- Disturbed sleep
- Heart palpitations (feeling like your heart is racing)
Risk Factors for Sick Sinus Syndrome
The exact cause of SSS remains unknown. However, there are some risk factors associated with this condition:
- A previous heart attack (a.k.a. myocardial infarction)
- Hyperkalemia (excess potassium in the blood)
- Sleep apnea
- Age
- Certain blood pressure lowering medications
- Thyroid disease
- Heart surgery
In rare cases, SSS may be associated with other conditions such as:
- Hemochromatosis (excess levels of iron in the blood)
- Amyloidosis (a condition where a protein called amyloid is deposited in tissues)
- Diphtheria (an infection that may damage the heart muscle)
- Muscular dystrophy (an inherited condition where the body’s muscles are weak and damaged)
