Heart Attack / Coronary Artery Disease
Ischemia means that the flow of blood (and therefore oxygen) to a part of the body has been reduced; cardiac ischemia means not enough blood and oxygen are flowing into the heart muscle, which can severely damage it and lead to a heart attack. In this episode of Second Opinion, you'll learn how to recognize the symptoms of cardiac ischemia, how it is treated, and how you can take steps to prevent it.
The heart is a muscle, about the size of a fist, whose main job is to pump blood to all parts of the body, bringing needed nutrients and oxygen and delivering waste products to other organs for removal. The heart has four chambers. The upper two are the atria (the right and the left atrium) and the lower two are the right and left ventricles. These chambers contract in a regular sequence, or rhythm (the heartbeat); the contractions enable the heart to pump blood. The rhythm of the contractions is controlled by the heart's "pacemaker," a group of cells in the right atrium (called the sinoatrial node, SA node, or sinus node) that generate electrical impulses. This is the "normal" rhythm, usually at a rate of 60 to 100 beats a minute. These impulses travel across the heart's chambers, making them contract.
The coronary arteries are the blood vessels that bring blood to the heart. When these arteries become hard and narrowed, the blood supply to the heart becomes reduced. Arteries usually harden and narrow because they get clogged with a fatty substance called plaque. This condition is known as coronary artery disease, coronary heart disease, or atherosclerosis and is a leading cause of cardiac ischemia. Sometimes the plaque in the arteries ruptures or tears; a blood clot can form, badly blocking the artery, which can lead to a heart attack. The coronary arteries can also be narrowed by spasm, and sometimes the narrowing is from a thick cholesterol deposit known as a "soft" plaque.
A heart attack means the supply of blood and oxygen to the heart has been so drastically reduced that cells in the heart die. The more severe the heart attack, the more heart muscle dies. The technical name for the heart muscle is the myocardium, and the most widely used technical term for a heart attack is myocardial infarction. But you may also hear the terms coronary thrombosis or coronary occlusion.
Cardiac ischemia usually causes chest pain, a condition known as angina or angina pectoris. But you can have cardiac ischemia with no pain, no symptoms. This is called "silent ischemia," and an individual may not be aware of the ischemic episode. One can even have a heart attack with no symptoms at all, called a silent heart attack.
But the good news is that heart attacks are no longer necessarily fatal. Better understanding of the causes, signs and symptoms of heart disease plus new treatment methods mean that the majority of people who have a heart attack now survive.
Cardiac ischemia can also cause arrhythmia , an abnormal heart rhythm. For more information about arrhythmia, watch the Heart Rhythm Disorder episode of Second Opinion and visit its web page.
Ischemia means that the flow of blood (and therefore oxygen) to a part of the body has been reduced; cardiac ischemia means not enough blood and oxygen are flowing into the heart muscle, which can severely damage it and lead to a heart attack
A heart attack is not a death sentence. Today, the majority of people who have a heart attack survive it and go on to live normal, active lives. Following a program of secondary prevention (usually involving taking medicines and making some lifestyle changes) can prevent a second heart attack.
Although some risk factors for a heart attack are beyond our control, many more are not. To prevent a heart attack, live in a "heart-healthy" way. That means:
- Get more physical exercise
- Stop smoking
- Stop drinking alcohol heavily
- Keep your blood pressure under control
- Keep your cholesterol under control
- Eat a heart-healthy diet
How often does the average heart beat (expand and contract) each day? About 100,000 times. How much blood does it pump? About 2,000 gallons. If you live to age 70, your heart will beat more than 2.5 billion times.
Learning CPR (cardio-pulmonary resuscitation ) takes only a few hours, and when you do, you may save a life! Contact your local chapter of the Red Cross or American Heart Association to find out when and where courses are given.
Ask Your Docotor
Provided by Nora Goldschlager, M.D.
Director, Coronary Care Unit, San Franciso General Hospital
Professor of Medicine, University of California, San Francisco
This list of questions is a good starting point for discussion with your doctor; however, it is not a comprehensive list.
- What are the risk factors for coronary artery disease?
- What causes a heart attack?
- What's the role of stress?
- Does alcohol cause heart attacks?
- My cholesterol is normal - why should I take medicines to lower it even more?
- What is angina and how do I know if I have it?
- What sorts of symptoms should I be watching for?
- How do they treat angina?
- When should I suspect that I am having a heart attack?
- When do I go to the emergency room?
- What are the complications of having a heart attack and not getting early treatment?
- What's an angiogram?
- What's an angioplasty? What's a stent? Do these things work?
- What's a 'clot-busting' drug?
- What's a bypass procedure? How long does it take, how long do I have to stay in the hospital, and when can I go back to work?
- Why do some people get recommended for bypass operations and others for the balloon procedure?
Key Point 1
Early intervention to protect the heart is critical, so seeking help quickly and describing your symptoms accurately will lead to a faster diagnosis and faster treatment. Heart attack symptoms may present differently in women than in men.
You can have cardiac ischemia with no pain and no symptoms. This is called "silent ischemia," an ischemic episode the person does not know about. This is especially true for people with diabetes. You can even have a silent heart attack, one with no symptoms.
However, the typical symptoms of heart attack include:
- Chest pain or discomfort
- Can feel like squeezing, pressure, or fullness
- Can last more than a few minutes, or come and go
- Pain, discomfort or numbness in other parts of the body, especially
- One or both arms and/or shoulders
- Jaw and/or tooth
- Stomach or abdomen
- This pain can be mistaken for gastrointestinal symptoms, such as heartburn
- Shortness of breath
- Cold sweat and/or clammy skin
- Nausea and/or vomiting
The more of these symptoms you have at the same time, the more important it is to get medical help as soon as possible.
A heart attack can be diagnosed through a variety of tests, including:
- Electrocardiogram (EKG, ECG, or cardiogram): a measurement of the heart's electrical activity (which controls the heartbeat) by an EKG machine (which is attached to the chest with electrodes)
- Echocardiogram: sound waves are bounced off the heart to produce still and moving images of it (similar to ultrasound imaging used with pregnant women to produce images of fetuses.)
- Cardiac catheterization: in this more invasive test, a small tube (catheter) is inserted through a blood vessel and threaded up into the heart, to measure blood flow and pressure
- Coronary angiogram (also called arteriogram): an x-ray of the inside of the coronary arteries to look for blockages
- During cardiac catheterization, a contrast dye is injected into the catheter that enables blockages to be seen on the x-ray
- Blood tests: when cells (including heart muscle cells) die, enzymes are released into the blood; blood tests can detect the presence and amount of these enzymes
Key Point 2
Secondary prevention, which is prevention of another heart attack after a heart attack, and includes drugs, diet and exercise, does work very well. It reduces the risk of a second heart attack by 50% to 80%.
Of course, the first step in preventing a second heart attack is to treat the first one effectively. The purpose of all treatments is to increase blood flow to the heart muscle. A variety of treatments are currently available, most involving medication and/or surgery.
As indicated in the program, recovering heart attack patients are often asked to take a "cocktail of drugs," that is, several medicines at the same time, on a prescribed schedule. These medicines can include:
- Anticoagulant drugs to prevent blood clots that can block blood flow to the heart
- Aspirin, also useful in preventing blood clots
- Other classes of drugs, such as antiplatelet agents, that also prevent blood clots,
- Plavix, mentioned in the program, is a brand name for clopidogrel, an antiplatelet agent
- Thrombolytic drugs to dissolve blood clots
- To be most effective, thrombolytics must be given within one hour of start of symptoms
- Beta blockers : drugs that slow down the heart rate, correct arrhythmias (irregular heartbeat) and reduce blood pressure, all of which helps lower the heart's workload; they can also reduce chest pain and fluid retention
- ACE inhibitors (angiotensin enzyme inhibitors) : drugs that act as vasodilators, that is, they open ("dilate") the arteries, lowering blood pressure and the heart's workload. ARB's, angiotensin receptor blockers work in a similar manner.
- Nitrates (including nitroglycerin): drugs that relax blood vessels and reduce the work load of the heart
- Statins : a class of drugs that help lower lipid levels in the blood and have anti-inflammatory properties, stabilizing the inner walls of the coronary arteries
- Other cholesterol lowering drugs
- Antiarrhythmic drugs that stabilize an irregular, fast or slow heart beat
- Diuretics: drugs that help eliminate excess fluid, and therefore aid the heart in working more efficiently
There is also a wide variety of surgical methods to treat heart attack. One commonly used technique to widen a narrowed artery is called angioplasty (or balloon angioplasty). A small tube (catheter) is inserted through a blood vessel and threaded up into the heart and into the coronary artery needing treatment. A balloon located on the catheter is inflated and reopens the artery. Sometimes, a spring-like device called a stent is used with a balloon. Because a blood clot can form around a stent, a clot preventing drug, such as clopidogrel mentioned above, may be prescribed. Often a balloon angioplasty and/or a stent work permanently, but sometimes the procedure has to be repeated.
Another important surgical technique is coronary artery bypass grafting popularly known as "a bypass." As its name implies, its purpose is to allow blood to bypass or go around a blocked artery. During the procedure, blood vessels from other parts of the body (usually arteries from the chest, arm and veins from the leg) are grafted into place to create a detour around the blockage in the coronary artery. This process is also known as revascularization.
There are many other surgical options depending, of course, on the nature and severity of the heart attack. They range from implanting a pacemaker if a slow heart rate caused the heart attack (a tiny device that sends electrical signals to the heart to restore its regular rhythm) in a person's chest, to giving them a new heart through a heart transplant.
For information about many of these options, watch the "Heart Failure" episode of Second Opinion and visit its web page. You can also learn about them at the American Heart Association's web site.
Along with the continued use of medications, secondary prevention includes a medically supervised cardiac rehabilitation program. This program normally has several components, such as directed exercises (under the care of a physician or nurse) and important lifestyle changes to minimize the risk of another heart attack, such as:
- Changes in diet to reduce obesity, lower cholesterol and lower blood pressure
- Other steps to lower cholesterol, lipids, and blood pressure
- Stopping smoking
- Controlling diabetes
The most important part of any rehabilitation program is that the person commits to it as lifelong therapy. Medical and psychological counseling are available to help people help themselves and give them the emotional support they need while making changes in their lives - changes that can save their lives.
Key Point 3
Primary prevention - prevention that will keep you from having a heart attack in the first place - works. If you never have a heart attack, you won't need that cocktail of drugs that helps prevent a second one.
Primary prevention begins by understanding the risk factors and causes of heart attack.
Some risk factors are beyond our control, such as:
- Genetics: a family history of heart disease and early heart attack can increase one's risk of heart attack
- Age: the coronary arteries narrow with age, so that men over 45 and women over 55 are at a higher risk of having a heart attack
- Diabetes: individuals with diabetes have coronary artery disease and are at risk for hypertension (high blood pressure), both of which can lead to heart attack
- A previous heart attack, or history of coronary artery disease, high blood pressure, and other heart problems: these can all increase one's risk of having a first or second heart attack
But we can control many other risk factors. They relate to how we live, and we can always change that if we try. These risk factors include:
- Not controlling high blood pressure
- Not controlling diabetes
- Not getting enough exercise
- Obesity and not controlling weight gain
- A "heart unhealthy" diet
The single most important cause of heart attack is coronary artery disease. Coronary artery disease (or atherosclerosis) is a general term for any condition that blocks blood flow through the coronary arteries. Usually, what blocks blood flow is a fatty substance called plaque that is deposited on the inner lining of the arteries. As these deposits build up, the arteries become narrower and blood flow is reduced.
All of the controllable risk factors can contribute to the onset of coronary artery disease. For example, a leading cause of coronary artery disease is hypercholesterolemia - too much cholesterol in the blood, or more precisely, dyslipidemia. Cholesterol, a fat made up of several substances, can be a major component of plaque in the arteries. But we can partially control the level of cholesterol in our blood by controlling our diet.
So the logical conclusion is, primary prevention means living in a "heart-healthy" way.
And that means:
- Keep your cholesterol (lipids) under control; if you need lipid lowering medicine, get it and use it
- Eat a heart-healthy diet, which includes:
- Fruits and vegetables
- More fish, less meat
- "Good" oils, such as olive oil and canola oil
- Portion control, and fewer calories late in the day
- Antioxidants are nutrients and other substances that protect cells in the body from the damage caused by "oxygen free radicals" (molecules that seek to become oxidized, a process that harms body tissues and has been linked to many diseases, including stroke, heart disease, and cancer); antioxidants are found naturally in food but are also available as dietary supplements
- Important antioxidants include:
- Vitamins A, C, E and beta-carotene (found in carrots)
- Lycopene (found in tomatoes)
- Flavonoids (found in ginkgo biloba, black cherries, blackberries, bilberries and blueberries)
- Quericetin - a specialized flavonoid found in apples, onions, tea and red wine
- Coenzyme Q10 - a vitamin-like substance found in soy, whole grains, mackerel, and chicken
- Folates - foods rich in folic acid, such as:
- Green vegetables
- Strawberries, oranges, raspberries
- Nuts and seeds
- Get more physical exercise, including aerobic and resistance
- Stop smoking
- Drink alcohol only in moderation
- Keep your blood pressure under control; if you need blood pressure lowering medicine, get it and use it
You can learn more about the risk factors for heart attack from the American Heart Association.
Conduct an off-site search for Heart Attack or Coronary Artery Disease information from MedlinePlus. These up-to-date search results are based on search terms specific to Second Opinion Key Points.