Sick Sinus Syndrome

Sick sinus syndrome (SSS) is a type of bradycardia (heart rates that are too slow) in which the sinoatrial node (the heart's natural pacemaker) is not functioning as it should. This means that the electrical signal that starts a heartbeat either moves too slowly through the SA node (sinoatrial block) or that there are pauses in delivery of the electrical signal (sinus arrest). Sick sinus syndrome can also cause tachycardia (heart rates that are too fast) or bradycardia-tachycardia syndrome (heart rates that fluctuate between being too slow and too fast).