What is sick sinus syndrome?

Any interruption in the normal flow of the electrical signal through the cardiac conduction system can cause an abnormality in the heart's rhythm. The electrical signals originate in the upper right chamber (atrium) of the heart in a region called the sino-atrial or "SA" node. The SA node can "slow down" as the result of the normal aging process. This can cause the heart to beat too slowly or fail to accelerate the heart rate with normal activity/exercise. The condition is called "sick sinus syndrome." The slowly beating heart does not circulate enough blood to meet the metabolic needs of the body and resultantly can cause fatigue, activity intolerance, or potentially even loss of consciousness (syncope).
Sick sinus syndrome is a heart-rhythm disturbance, or arrhythmia, that involves a group of symptoms, such as the heartbeat switching from too slow to too fast. The heart’s electrical signals control its contractions and your heartbeat. The source of these signals is the sinoatrial node in the heart. Collectively, the symptoms of sick sinus syndrome indicate that the sinoatrial node is not working properly.

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