What is sick sinus syndrome?Sick sinus syndrome, also called Bradycardia-tachycardia syndrome is a group of abnormal heartbeats (arrhythmias) presumably caused by a malfunction of the sinus node, the heart's "natural" pacemaker. Sick sinus syndrome is a disorder of the sinus node of the heart, which regulates heartbeat. With sick sinus syndrome, the sinus node fails to signal properly,
resulting in changes in the heart rate.
The sinus node in the heart functions as the heart's pacemaker, or beat regulator. In sick sinus syndrome, patients normally will experience bradycardia, or slowed heart rate. Also, it is not uncommon to see fluctuations between slow and rapid heart rate (tachycardia). This makes the diagnosis and treatment of sick sinus syndrome more complicated than most other cardiac arrhythmias (irregular heart beats). A sick sinus node may be responsible for starting beats too slowly, pausing too long between initiation of heartbeats, or not producing heartbeats at all.
Sick sinus syndrome 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).