Gettysburg Medical Center
 The Clinical View
 by P.E. Hoffsten, M.D.
 2 February 2005

WHAT IS AN AICD?

            This is a column about two people.  They are representative of many people who have an AICD.  Those initials stand for “automatic implantable cardiac defibrillator”.  To explain what an AICD is and what is does, I need to first explain the problem that it deals with.

            As most people know the most common cause of death in the United States has to do with heart disease.  Basically, the cause of death is that the heart stops beating and blood circulation ceases.  About 1 in 5 people that die do so “suddenly, unexpectedly”.  When I have discussed this with groups before, there is always someone in the audience that says that everybody dies suddenly.  One moment their heart is beating, the next moment it is not.  That seemed pretty sudden to them.  The pivotal word here is unexpectedly.  This is the person sitting in their easy chair at 50 years of age with no hint that there is anything wrong and they die sitting there.  It is the person walking down the street having no clue that there is a problem and simply falls down dead in the street.  Believe it or not, 20% of all the deaths in the United States occur unexpectedly.

            Over years of research, we have learned that those people who die “suddenly unexpectedly” do so because their heart develops a condition called ventricular tachycardia which then leads to ventricular fibrillation.  These two words describe the condition of a heart that vibrates and quivers but doesn’t have any effective heart beat.  It is due to the electrical current that runs the heart, short circuiting and not leading to a rhythmic heart beat as is normal.  This electrically chaotic condition develops in hearts that don’t get enough blood or in hearts that are fatigued or in hearts that are sick for various other reasons.  But ventricular fibrillation is the final common pathway for the majority of sudden, unexpected deaths.

            What if there was a way to predict who is likely to develop ventricular fibrillation.  Through many more years of research, we have learned that there are certain characteristics that a person might have that predict the likelihood of unexpected death.  Your local clinics can help identify people that are at high risk for this problem.  When these individuals are identified, they are referred to a special kind of heart doctor called an electrophysiologist.  The electrophysiologists evaluate the patient and determine the likelihood that they will develop ventricular fibrillation and then select those at highest risk for placement of an AICD.

            In the 1950’s it was learned that a direct electric shock applied to a heart that is fibrillating will line up all the electrical circuits again and frequently lead to the heart returning to a normal rhythm as it had before the ventricular fibrillation.  Many people have probably seen this depicted on television where the paddles are applied to a person’s chest and an electric shock is delivered.  The person seemed to bounce off of the bed and sometimes will return to a normal rhythm.  An AICD is a device that does this for the person.  The device is about the size of your smallest cell phone.  It is implanted usually in the left upper shoulder area.  It is connected to the heart through two wires that go through a vein in the upper chest.  The AICD has a built in electrocardiogram recorder.  It monitors every heart beat and when it sees that a person has developed ventricular fibrillation, it will deliver a shock to convert that rhythm back to normal.  The newer devices are so sophisticated that they can often correct an abnormal rhythm before it deteriorates into ventricular fibrillation.  When the shock from the AICD occurs, it is definitely an attention getting event.  It is physically very disruptive but also the symbolism of what it represents is very frightening.

            Recent data have shown that the AICD is a better device for preserving life and well being than any of the drugs that we have used in the past.  Unfortunately, an AICD is very, very expensive but fortunately now covered by Medicare for those that have qualifying clinical situations.

            The first person to describe in this column was a gentleman who had no inkling that he had anything wrong with his health.  He developed chest pain and had a myocardial infarct (heart attack).  He came to the hospital and on arrival he had ventricular fibrillation and a cardiac arrest.  He was treated with an electric shock that re-established his normal rhythm.  Over the next several days, his course was very stormy with several additional cardiac arrests.  Each time the nurses and doctors helping care for him would shock him back to a normal rhythm.  By the third time this happened, he was flown to a heart center and an AICD was placed in his chest.  Fortunately, he recovered from his heart attack and now three years later continues his normal function as a father, grandfather, cattle rancher, and avid fisherman.  His AICD has discharged twice in three years.  Each time it discharged, he was unusually fatigued and he was warned about that problem.  He has not had a discharge from AICD now for 18 months.  It seems that those electric shocks provide wonderful negative feedback telling the person that they probably shouldn’t get fatigued.  This is a person whose life has been spared with productive and enjoyable time that would not have been his except for his AICD.

            The second person to talk about in this column is an elderly lady who had her AICD placed twelve years ago.  Through the years, it had discharged only twice but recently, she had become infirmed and clinically ill.  She developed a pneumonia and the strain on her heart with this led to ventricular fibrillation and her AICD discharged with a painful shock.  She came to the hospital and antibiotics and various other steps were taken.  Unfortunately, she had multiple other medical problems and it was highly likely that she was going to have a mortal outcome in the near future.  She requested that her AICD be turned off so that she could pass away in peace without having to undergo a large number of shocks bringing her back to nothing but more grief.  Quite appropriately, a device very much like the remote control for your TV set was directed to the AICD in her chest and the AICD was turned off.  Shortly, thereafter, she did pass away in peace without the need for further shocks.  So there is a time to use an AICD and there is a time to stop.

            The healthcare providers at your local clinics are well aware of the above considerations and recent research has shown clearly that individuals with an AICD live longer and more comfortable productive lives than those who elect not to use them or those who use medications alone.