Episode 36: February 24, 2010
by Rob Lamberts, MD
My last article covered how to know when chest pain is serious. Today I’m going to back up and discuss the disease that is the most common cause of the chest pain you should worry about: coronary artery disease.
What Causes a Heart Attack?
The coronary arteries are the blood vessels that supply blood to the heart. The heart’s job is to pump blood; the heart also needs its own blood supply to bring it oxygen and food. If that blood supply is cut off, the heart muscle cells can’t survive--they suffocate.
If that blood supply is cut off suddenly, it’s called a heart attack. Doctors call it a myocardial infarction, but you know how doctors are. The process that leads to the heart attack occurs over the course of many years, whereas the heart attack itself can kill in seconds. Here are the 3 steps that lead to a heart attack.
Step 1: Fatty Blisters Form
The first thing that can lead to an eventual heart attack is the formation of fatty blisters on the inside of the coronary blood vessels. These blisters are part of what is known as atherosclerosis, which means “scarring of the arteries.” You probably have heard these blisters called “cholesterol plaques” or “fatty deposits.” Why do these plaques form? The consensus among those smart scientists is that they are the result of a number of things, including: high blood pressure, toxins from cigarettes, high LDL cholesterol (which is the bad cholesterol), and diabetes. Some people are predisposed to atherosclerosis, presumably because the walls of their blood vessels don’t function properly, and so form plaques more easily. Age is also an important factor, as even smaller trauma to the blood vessels will mount up over time.
The big event in a heart attack is when a blister in the coronary artery bursts. Upon rupture, the substance in these plaques causes a blood clot to form, which blocks off the flow of blood in the artery
There are a lot of other factors involved, like inflammation, chemicals, and probably some covert conspiracy of big business and the CIA (as is the case in most areas of life); but I’m going to leave the fancy scientific stuff to those smart scientists. What you need to know is that these fat-filled blisters form over a number of years, and the best way to prevent a heart attack is to prevent these plaques from forming
Step 2: The Blister Bursts
The big event in a heart attack is when a blister in the coronary artery bursts. Upon rupture, the substance in these plaques causes a blood clot to form, which blocks off the flow of blood in the artery. The heart muscle downstream from the blood clot gets starved for oxygen, and this is what causes the chest pain. Depending on which coronary blood vessel is blocked, and how far upstream the blood clot occurs, the clot may threaten to kill a small amount of heart tissue, or nearly the entire heart.
What exactly causes this fatty blister to burst? A lot of times, we don’t know what brings on the final event, but intense exercise--especially in people who are out of shape--as well as other stressors on the body, such as infection, can cause plaque rupture.
Step 3: The Heart Suffocates
The third step in the process happens over the course of minutes. The heart tissue that is starved for oxygen can survive for about 20 minutes before it dies off. That is why I said in my last article that continuous pain lasting more than 20 minutes is not likely to be a heart attack. If a small part of the heart is cut off from oxygen, the person may not even know they’ve had a heart attack. If it is a large part of the heart that is cut off, it is critical to get help as soon as possible.
Why Heart Attacks Kill
Two things can kill a person from a heart attack: either the heart tissue dies off and so the heart can’t pump enough to keep the person alive, or the heart goes into a fatal heart rhythm, known as ventricular fibrillation. Both of these are not necessarily fatal, as emergency care can lessen their damage and save the person’s life.
How to Treat a Heart Attack
Did I mention that time is of the essence in treating a heart attack? Restoring the blood flow and treating the heart arrhythmias that happen as a result can save a person’s life. I need to make sure I mentioned this small fact: RESPONDING QUICKLY TO A HEART ATTACK CAN SAVE YOUR LIFE.
What can be done to save a person’s life? The first thing is something you can do at home. Take an aspirin; take two baby aspirin, which are 81 mg each, or a whole 325mg aspirin. Chewing it will make it enter your bloodstream faster. Aspirin has several effects that help fight a heart attack, the main one is to decrease the blood’s ability to clot.
Other medications, known as “clot busters” can break up clots and return normal blood flow. They can only be given at the hospital, which again, is why responding quickly to a heart attack can save your life. Dangerous heart rhythms can also be treated or prevented at the hospital.
Quick and Dirty Tips for Heart Attack
Let me finish with my quick and dirty tips for heart attack.
Tip 1: Prevent It
If you have any of the risk factors for heart disease, please see your doctor and do what you can to prevent a heart attack. If you aren’t sure you have any of these risk factors, ask your doctor. You don’t want to find out in the emergency room.
Tip 2: If You Have Chest Pain, Get Seen as Soon as Possible
Did I mention this? Don’t delay! Get seen as soon as you can! Don’t page your doctor. Don’t call your neighbor. Get help as soon as possible! Don’t be embarrassed. You’d rather go in for gas, than stay at home with a heart attack. Time is of the essence. Don’t delay! I am sure I said that at least once.
Tip 3: Be Prepared
Keep aspirin on hand and chew one up immediately if you think you may be having a heart attack. It’s also good to learn CPR so that if someone around you does have a heart attack, you can keep them alive long enough for them to get help.
That’s all for today. My next article will cover all of the tests and procedures that are done for the heart, like EKG’s, stress tests, bypass surgeries, and heart catheterization.
If you have subjects you want me to cover, send them to firstname.lastname@example.org. You can find me on Twitter as @housecalldoc and on Facebook under “House Call Doctor.”
Let me remind you that this podcast is for informational purposes only. My goal is to add to your medical knowledge and translate some of the weird medical stuff you hear, so when you do go to your doctor, your visits will be more fruitful. I don’t intend to replace your doctor; he or she is the one you should always consult about your own medical condition.
Catch you next time! Stay Healthy!