Sick Sinus Syndrome

Sick sinus syndrome (SSS) is a type of bradycardia 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). SSS 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).

Normal Rhythm

Every heart has a normal rhythm. That rhythm varies from person to person. In most healthy people, the heart at rest beats about 60 to 100 times per minute. A small bunch of heart cells called the sinoatrial node keeps time.