As many of you already know, Carrie Fisher suffered a cardiac arrest while inbound to LAX on a United Airlines flight yesterday (more of the news here). Thankfully, she was successfully resuscitated, and is now undergoing intensive care at UCLA. Hopefully she will make a full recovery, and many fans around the world are following the frightening story closely. This may come up as a topic of conversation around your house during Christmas dinner.
As an emergency physician and cardiac arrest researcher for the past 15 years, I thought it would be helpful to share with you some basic information about cardiac emergencies. The media often confuses things terribly by mixing up terms such as “heart attack” and “cardiac arrest”, two very different problems with different treatments. Follow me below the fold for what I hope is a useful primer on cardiac emergencies. One day, you might unfortunately find yourself in a situation where this information could prove useful and even life-saving.
THE BASICS: HOW THE HEART WORKS
To understand cardiac emergencies, a brief review of how the cardiac system is organized is required to set the stage.
The heart is basically a pump. By sequentially squeezing and relaxing (known as “systole” and “diastole” , respectively), the heart pushes blood forward in the circulatory system, feeding vital organs and tissues throughout the body. Like any mechanical pump (or your car’s engine, for that matter), there are two other required elements to make everything work, beyond just the pump itself. These two elements are a control system (that is, the thing that makes the pump start and stop in coordinated fashion) and an energy supply (since pumps do work, they need an energy input).
The control system for the heart is basically an electrical wiring network composed of specialized heart tissue designed to coordinate the squeezing and relaxing actions. Crucial in this control system is the pacemaker (known as the “sinatrial node”) that gives us our heart’s rhythm, sending out regular impulses that say “beat….beat...beat” — these impulses usually range from 60-100 per minute but can vary depending on what we need from moment to moment. These impulses are then carried throughout the heart by the electrical system, allowing for well-organized beating of the muscle.
The energy supply for the heart comes in the form of blood flow, rich in oxygen and glucose, that is conveyed by the coronary arteries. The coronary arteries are relatively small (3-4 mm internal diameter, smaller than the width of a pencil), and they are essential for the heart muscle to be fed. As you can imagine, heart muscle squeezing day and night takes a lot of energy, and without interruption. Think it’s bad when your home power goes out in a storm? At least you have back up system options (candles, battery-powered flashlights, nearby restaurants for food) — the heart doesn’t, more or less. If the power goes out (no coronary blood flow), big problems ensure. That comes next in our discussion.
So, summary so far — the heart is composed of three basic functions
THE PUMP — the cardiac muscle itself
CONTROL SYSTEM — electrical wiring to manage pump
ENERGY SUPPLY — blood via the coronary arteries
So now you are equipped with everything you need to understand what happens when things go horribly wrong.
ENERGY SUPPLY DISRUPTION: HEART ATTACK
We’ve all heard the term “heart attack” in popular culture, in the news, and unfortunately from friends or family. What IS a heart attack?
From a multitude of factors, including high blood pressure, smoking, enjoying a diet with too much fat (editorial note: I am guilty of this one too, lest you think I’m preaching), many of us will develop blockages in coronary arteries. Basically, the pipes accumulate “crud”, spoken plainly. Just like the pipes in your home, when the crud builds up too thickly, it impairs the flow of fluid. When coronary arteries get this build up, blood flow is compromised. Now the good news is that the heart can make do with partial blockages (amazingly, even a 70% blockage of a big coronary artery may not yield any symptoms or noticeable problems). What the heart DOES have problems with, however, is the sudden 100% blockage of a coronary artery, usually from a combination of this crud building up plus an acute blood clot that forms as a reaction to this build-up (I’m skipping some biology here regarding the reason for the clots, please forgive me, but trust me when I say that what I have told you is basically true). When you get a sudden blood clot at the site of the build-up, you have a heart attack (also known as a “myocardial infarction”). If the blockage isn’t fixed quickly (within 1-2 hours), a small piece of heart muscle may die, and future pump function will be impaired.
Practical information on heart attacks: when people have heart attacks, they usually don’t collapse. They don’t become unresponsive. What they DO experience, however, are symptoms such as chest pain, shortness of breath, sweating, or vomiting. Often all of these symptoms occur at the same time, and come on fairly suddenly. What do you need to do? If someone has sudden chest pain and sweating, for example, you should call 911. They need to get to the hospital, and fast. Often these symptoms aren’t from a heart attack, but leave that to the ER team. If it is a heart attack, emergency procedures may be required, chiefly among them being ANGIOPLASTY, where cardiologists snake tubes into the blockages and break them up (think roto-rooter for your home plumbing, it’s really that similar). Another truly life-saving tip: if you have a loved one with heart disease or risk factors, and they develop sudden chest pain, they should be given an aspirin as soon as possible (in fact, most ambulance crews will give aspirin for these situations, if you haven’t already administered one) — aspirin reduces the ability of blood to clot, and can thus reduce the chance of a clot making a 100% blockage. Strong medical evidence shows that aspirin can be life-saving. What NOT TO DO: if a loved one has symptoms of a heart attack, but is awake, they DO NOT need CPR (cardiopulmonary resuscitation). That is a treatment for cardiac arrest, coming next in this discussion.
CARDIAC ARREST: THE BIGGEST KILLER THAT NO ONE FULLY APPRECIATES
Above, we talked about the energy supply going bad. But what if the electrical system fails? In some cases, a serious electrical system failure can actually lead the heart pump to stop working altogether — this is known as CARDIAC ARREST. Unlike heart attack (where the energy supply has a partial failure), when the electrical system (and thus the pump) suddenly fails, the heart very likely will stop beating. Without a heart beat, a person becomes unresponsive within seconds. They stop talking, stop breathing, and stop moving. Technically, this person is dead UNLESS something is done, and quickly, to restore blood flow throughout the body.
Cardiac arrest strikes over 300,000 people in the US each year — and over 80% of people die from this abrupt condition. And yet, would it surprise you to know that the majority of people in the US haven’t been CPR trained in the past decade? Or that over 70% of cardiac arrest victims don’t receive CPR from onlookers? If you need some context from links to real-life stories, Tim Russert, Michael Jackson, and James Gandolfini all suffered cardiac arrest. If you want a recent story of cardiac arrest survival, check out the amazing story of UK football star Fabrice Muamba. And, of course, Carrie Fisher — who we hope will survive much like Mr. Muamba.
This is CPR (cardiopulmonary resuscitation)
Practical information on cardiac arrest: The most important thing you can do — learn CPR! In my opinion, this is essential life instruction in the modern world, much like learning to swim. Most cardiac arrest events occur in the home setting (after all, that’s where we spend most of our time) — and what would you do if your loved one suddenly collapsed next to you? Calling 911 is essential, but it will take precious minutes for the ambulance to arrive (in most big US cities, 8-10 minutes). It is essential to know that survival from cardiac arrest falls by 10-15% for every minute spent without CPR. So calling 911 is not enough. Immediate CPR is essential.
This is an older model defibrillator
The other thing to know — remember we talked about how cardiac arrest is often a failure of the electrical system? Well, sometimes the best way to get an electrical system to behave is do a “hard reset” (you all know about this from your home computer, sometimes the “blue screen of death” is best fixed by just turning the darn thing off and back on 10 seconds later). In medical terms, an electrical hard reset is accomplished by a defibrillator, shown on the left. There are defibrillators that you can use, available in airports, gyms, train stations, and many other public locations. These are simplified, easier to use devices known as automated external defibrillators, or AEDs. In theory, they are designed to be used without any previous training or experience.
SO IN SUMMARY….
I hope you found this a useful diary in light of Carrie Fisher’s unfortunate experience. Now you know the difference between a heart attack and a cardiac arrest, and you know the key features of how patients appear with both conditions. You also are now aware of the required treatments.
Here are some useful links that you may seek out if you want to learn more:
CPR basics with a video, from a well respected CPR research team
Finding CPR classes through the American Heart Association
A reputable YouTube video on heart attacks and cardiac arrest
Site that houses the international guidelines on CPR and AED use
May you have a peaceful and healthy holiday season, free from cardiac emergencies. I, for one, will be working in the ER tonight — and hopefully I won’t need to perform CPR. But in emergency medicine, you never know what is going to happen on a given shift — CPR may be in my future just hours away.
Sunday, Dec 25, 2016 · 12:12:40 AM +00:00
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ERdoc in PA
Thanks for the rec list! Glad to help this amazing community with some medical education. I’ve often toyed with the idea of a regular diary on emergency medicine topics — let me know if you think this is a good idea, and maybe I’ll motivate to get ‘er done.
