A relatively common heart abnormality that in the past had a significant fatality rate is called the “sick sinus syndrome”.  This clinical problem has to do with the clock that tells the heart how fast to beat.  In people with the “sick sinus syndrome” the clock gets tired and just runs too slow letting the heart rate drop so low that it doesn’t provide enough blood to run the person’s body.  Patients would have heartbeats at 30-40 beats per minute (normal heart beat 60-100 beats per minute).  When these very slow heart rates occur, these individuals become very easily fatigued, lack energy and often die from heart failure.

     One of the true miracles of modern medical science is the electronic pacemaker that now effectively treats this condition.  People often shudder to think about “having a pacemaker”.  The truth is placing a pacemaker is a very simple operation and truly miraculous in regard to what it does for the patient.

     To understand how the pacemaker works, it first needs to be recognized that there is an upper chamber of the heart that pumps first and squirts an extra amount of blood into the lower big chambers of the heart. Then follows valve closures and the big chambers of the heart pump the blood out to the lungs and the body.  These two parts of the heartbeat are distinctly different and need to be timed just perfectly in order to get an effective heartbeat.

     With today’s pacemakers, a tiny wire is first passed into the upper chamber of the heart and then a second wire is passed into the lower big chamber of the heart.  These two wires are placed through a large vein that is just beneath the collarbone.  That vein leads directly to the heart, a short distance away.  The pacemaker packet is then implanted just beneath the collarbone in the soft tissue around the upper chest.  Old style pacemakers used to be as big as one of the little cereal boxes and had to be put in the abdomen.  The modern pacemakers are roughly twice the size of a silver dollar and the person really doesn’t notice the pacemaker in the upper chest.

     The amazing part of pacemakers is how diverse they’ve become in their function.  The electric circuits are now very sophisticated.  The electric wires in the two heart chambers can detect if a heartbeat has occurred.  If a heartbeat is detected at an adequate rate, then the pacemaker does nothing but sit and count heartbeats.  If it tuns out that the heart is beating too slowly, the pacemaker can sense that and then deliver a tiny electric shock to the heart to initiate a heartbeat.  The circuitry in the pacemaker allows the upper chamber to be individually sensed and paced and the lower chamber individually sensed and paced independent of the upper chamber.

     In the last fifteen years, a remarkably clever touch has been added.  In the tiny pacemaker is a small jelly capsule with a special electric crystal present.  When the person is moving and being more active, the jelly in the pacemaker gets shaken and the heart rate speeds up directed by the tiny electric crystal mentioned.  Thus, pacemakers are now what we call rate responsive.  When the person is sitting still, they allow the heart rate to return to a normal range.  When a person becomes more active, the pacer will allow a heartbeat to go up into the 80’s and 90’s to provide more blood flow for the person when they are active.

     Most of the time, pacemakers are placed in order to speed up a heart that is going too slow.  However, for some individuals very fast heart beats provide an opposite problem.  When the clock in the heart beats too fast, the heart doesn’t have time to fill up with blood and each heartbeat becomes relatively ineffective.  When this occurs, special pacemakers are now available that will sense this and turn down a heartbeat that has become too fast.

     Lastly, very sophisticated pacemakers are available that have an electric shock device built right into them to correct problems when the person has a cardiac arrest.  I recently reviewed the number of persons in my practice that had one of these devices in place and counted fourteen individuals just in central South Dakota that have the electric shock device (AICD) in place.

     In summary, a pacemaker can be both a life saving and a life improving device.  They are relatively easy to put in place, have very few complications and are something to be welcomed rather than dreaded.  The healthcare providers at your local clinics are aware of these considerations and can help identify individuals who might benefit from a pacemaker placement  when needed.