Sick sinus syndrome (SSS), is a collection of diseases: The heart cannot effectively perform pacemaking duties

Bradycardia-tachycardia syndrome, or sick sinus syndrome (SSS), is actually a collection of diseases where the heart is no longer able to effectively perform its regular pacemaking duties. A small area of the heart located in its right upper chamber is composed of special fibers in what is called the sinus node. It is responsible for all the normal and regular heartbeats we have when no one is thinking about it, as well as speeding the heart up when necessary (as in exercise or increased blood flow needs) and slowing it down (in periods of rest or sleep). When the sinus node malfunctions, or wears out, or is prevented from performing its “command” function in keeping an appropriate and regular rhythm, the heart rate no longer is regular (arrhythmia) or appropriate to the stimulating action in the body. It may provide an inadequate heart rate response to stress or exercise which, needless to say, can lead to serious consequences if not attended to.

While primarily a disease of those in their seventies and older, SSS can occur in much younger ages. It’s estimated that more than one in every 600 cardiac patients over the age of 65 has this syndrome. The majority of cases involves a “remodeling” of the tissues of the sinus node, such that they may become hardened or fibrosed and, as a result, less and less effective at putting out a signal strong enough for the heart to march to. Often coexisting cardiac conditions such as heart failure, heart blockages near the area, or infiltrative diseases such as sarcoidosis or hemochromatosis may be involved. Intrinsic cases such as electrolyte and metabolic disturbances or the actions of certain cardiac medications that slow conduction in the heart can mimic SSS, but withdrawal of the medication or correction of the imbalance generally restores the sinus node function to normal. Read More