Sick Sinus Syndrome
Normally, the heartbeat starts in an area in the top chambers of the heart (atria). This area is the heart's pacemaker. It may be called the sinoatrial node, sinus node or SA node. This keeps the heart beat steady and regular.Sick sinus syndrome is a group of heart rhythm problems due to problems with the sinus node, such as:The heartbeat rate is too slow, called sinus bradycardia The heartbeat pauses or stops, called sinus pauses or sinus arrestEpisodes of a fast heart rateSlow heart rhythms that alternate with fast heart rhythms, called bradycardia-tachycardia or "tachy-brady syndrome"