Sinus of the Heart

QUESTION: I am told I am suffering from a sick sinus in my heart. It may
mean that I must have a pacemaker put in to keep my heart beating, and I need
to know all I can about this. I thought sinuses were in your nose; can you
tell me about this sinus in my heart?
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ANSWER: Though the words are they same, the anatomical structures are quite
different. Sinuses in the head are open spaces in the bones of the head. The
sinus in the heart is called the "sinus node", and is made up of cells that
are responsible for kicking off the nerve impulses that control the beat of
your heart. These impulses travel along a conduction system within the heart
and assure that the rhythm and sequence of the heart muscle contractions will
propel the blood through the heart and thus through the entire body. The
"sick sinus syndrome" (SSS) is the condition in which the system of impulse
formation and conduction fails to operate properly, slowing the heart beat or
reducing its effectiveness. It is most common in patients over the age of 60
and is the reason for the placing of about half of the permanent pacemakers in
use in the United States. There are a number of diseases that can cause SSS,
including situations where the blood flow to the heart is reduced, infections
of the heart and rheumatic heart disease.