Inside Artery Disease: Peripheral and Carotid Artery Diseases
OCT 28, 2024Just as the pipes in your house can become clogged over years of use, the human body’s miles of arteries can become narrowed due to the buildup of plaque.
Read MoreHere's a morbid thought: Walk through the part of a cemetery housing newcomers and take a look at the grounds where the recently deceased were buried.
There are half a dozen pacemakers quietly toiling away under your feet, providing unneeded electrical impulses to their owners sixty times per minute while their batteries slowly deplete and wind their way down to lifelessness.
The devices function like the faithful dog standing at the doorstep of a deceased owner who will never return, without the slightest indication that their efforts will never again lead to the pulsating blood of a living body. This concept seems straight out of a horror movie with lifeless zombies being driven through the night by the incessant bustle of their artificial pacemakers.
The reality is not quite as morbid and much less exciting, despite the accuracy of the premise. We do not turn off pacemakers when patients die, nor do we remove them. Because people with pacemakers are repeatedly implanted with new batteries when the old one gives out, they are inevitably outlived by their pacemakers.
Just last week, I had a conversation with a relatively healthy patient who is a candidate for a pacemaker. He and his wife were full of questions after coming to the appointment prepared with extensive information from the Internet. One question concerned the man's ability to actually die as soon as he gets the device. "If I'm on my deathbed with cancer will the pacer keep me alive even when I want to pass away?"
It was this line of questioning that prompted me to write on this topic. I have had several other patients who have raised this issue and probably even more who wondered about it without having the courage to ask me. Surprisingly, a large number of doctors and nurses are also relatively naïve about the interaction between a functioning pacemaker and a non-functioning human being.
The purpose of a pacemaker is simple: it prevents your heartbeat from becoming too slow. Connected to the heart via wires called leads, the device spends its life searching for natural impulses emanating from the heart muscle. If your natural pulse drops below 60, or whatever our programmed number is, the pacemaker begins to stimulate the heart with an imperceptible electric shock once a second.
The current flows through the tip of the lead into the adjacent heart muscle and then spreads throughout the ventricle, moving from cell to cell at lightning speed. The stimulus triggers a short restructuring of the proteins and leads to a contraction of the muscle fibers. Within a fraction of a second, the entire ventricle expresses about one hundred milliliters of blood into the aorta.
To summarize this series of events:
Step 1. Pacer sends electricity to the lead tip.
Step 2. Electrical impulse conducts to tissue at the point of contact and spreads throughout the heart.
Step 3. The electrical impulse causes the heart to contract.
Now let's talk about what happens to the heart at the moment of imminent doom. One thing a healthy body is really good at is eliminating waste products (and, no, I am not complimenting you on your bathroom talents): the lungs eliminate carbon dioxide and the kidneys and liver break down and eliminate unwanted metabolic byproducts.
As these organs deteriorate, your blood becomes saturated with metabolic debris and becomes an inhospitable environment for normal cell functions. In particular, the pH of the blood drops and the normally neutral serum slowly turns into a weak acid. Once the pH drops by more than a fraction of a point, the heart muscle is no longer able to propagate an electrical stimulus or create an effective ventricular contraction.
In other words, no amount of external electricity will cause a contraction as soon as the heart muscle becomes electrically sluggish and mechanically dormant. Step 1 in the cascade described above does not matter if steps 2 and 3 fail. Therefore, we do not switch off pacemakers in dying patients - it simply makes no difference.
This, of course, does not stop people from asking us to decommission implanted devices. Occasionally, a doctor or family member will demand that we turn off a pacemaker in a dying patient and in the final stages of palliative care. Why not also remove pacemakers, when other life-saving services such as antibiotics, infusions and artificial ventilation are being scaled back?
I would like to clarify another concept: the purpose of a pacemaker for most people is to improve quality of life by increasing mobility, preventing fainting, and providing more energy. Indeed, it is somewhat unlikely that a patient's heart would simply stop beating without the services of a pacemaker.
In other words, for most pacemaker patients, their device is a quality-of-life improvement rather than a life-and-death therapy. I do not have exact figures on how many patients would simply die if their pacemakers were switched off today, but I would put them at no more than 20% of patients.
Switching off a functioning pacemaker in a terminally ill patient would most likely not result in their rapid death. In a patient who dies but is not yet on his deathbed, such an intervention would most likely lead to a dramatic deterioration in the quality of life without speeding up the end of life, with the patient suffering even more exhaustion and periodic falls or unconsciousness.
Handling pacemakers in the terminally ill population is by no means straightforward and is often discussed in the medical literature. In the US, there is no law against switching off a pacemaker in dying patients (such laws exist in some countries), and the consensus among experts is that artificial pacemaking is nothing more than artificial ventilation and can be removed with the consent of the patient, family and caregivers. However, the simple fact remains that such a decision makes little difference to the final outcome of the patient for most patients and can cause undesirable results before death.
This issue is very different from that of the implantable cardioverter defibrillators in this patient group. This device differs from a pacemaker in its ability to deliver a shocking shock to the heart in the event of cardiac arrest. In a patient dying of other causes, it would be a blessing rather than a curse to die suddenly and without sudden arrhythmias. We routinely offer to deprogram the shock function of the ICD for patients like these, allowing them to die without the intrusion of a 35-joule kick into the chest.
In short, if you are a patient with a pacemaker, you can stop worrying about your device keeping your body alive long after the rest of you leave this earthly existence. There will be no cemetery escapees or zombies roaming the streets at night in search of edible brain tissue.
Your pacemaker will be a reliable, useful companion for you until your body decides it is no longer needed. After that, your pacemaker will be no more alive than the fillings in your teeth or the artificial joint in your knee, slowly and quietly draining its battery while you move on to better things.
CHI Health Heart Institute's Cardiologists can talk with you about heart care for you or a loved one.
Original post date: April, 2011. Revised: January, 2019.
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