Did you know that your heart comes with its own built in pacemaker – the sinus node? I guess the fact that we come with a pacemaker already pre-installed and hard-wired into our system should be intuitive, especially since keeping the pace (or beat) is what our heart is, after all, design to do!
Unfortunately, just like the rest of our working and moving parts, they sometimes wear out, break down, or catch a cold. In other words, we (or parts of us) get sick: the sinus node is no exception. The problem with the sinus node is that when gets “sick,” it may come in the form of Sick Sinus Syndrome. Sick Sinus Syndrome is not your average run-of-the-mill illness and refers to a group of arrhythmia problems.
Much of the time (but not always) arrhythmias are pretty harmless. To understand an arrhythmia, think in terms of musical beat and rhythm. The beat is music is that steady underlying pulse that just keeps on going, never varying and moving the song along. On the other hand, rhythm can be described as the way the words go. It’s easy to see that while beat and rhythm each involve movement, they function in very different ways. That wonderful built in pacemaker, the sinus node, keeps your heart drumming out that steady beat. An arRHYTHMmia (see the word “rhythm” in there?), on the other hand, is not steady and may cause your heart to speed up or slow down. For persons with Sick Sinus Syndrome, the arrhythmia takes the heart someplace else entirely – someplace too fast (tachycardia), too slow (bradycardia), too irregular (and sometimes a combination of all those) – someplace away from that steady drum beat that our bodies so need.
Sick Sinus Syndrome comes in three flavors, all with different causes:
• Sinoatrial block: Slower than normal heart beat caused by electrical signals that slow down when passing through the sinus node.
• Sinus arrest: To go back to the musical analogy, think of a “rest” (a musical beat of silence). In sinus arrest, the sinus node takes a rest or pauses for a moment.
• Tachycardia-bradycardia syndrome: This form of Sick Sinus Syndrome gives the sufferer the full spectrum – heart beats that are too fast, too slow, and that pause (really long pauses called asystole).
Sick sinus syndrome can affect anyone of any age, although it’s most commonly found in persons over the age of 70 years. Causes can vary but may include scar tissue from earlier surgeries (especially in children) along with various medicines such as beta blockers or calcium channel blockers. Normal aging, of course, is a contributor to sick sinus syndrome. Let’s face it, as we age our body parts are just like tires – they lose a little tread and don’t hold up as well as when they are brand new. The treatment for sick sinus syndrome can be as simple as changing medications but most people with this eventually need an artificial pacemaker installed.
Sources:
Sick Sinus Syndrome, The Mayo Clinic, 23 May 2009, http://www.mayoclinic.com/health/sick-sinus-syndrome/DS00930
Heart Arrhythmias, The Mayo Clinic, 14 Feb 2009, http://www.mayoclinic.com/health/heart-arrhythmias/DS00290