Heart Attack = Blocked Arteries
A heart attack occurs when the coronary arteries become completely blocked by plaque rupture and thrombosis (blood clot formation), impeding blood flow to the heart muscle beyond this blockage.
Think You're Having a Heart Attack?
Call 911 immediately
If the flow of blood isn't restored quickly, the section of heart muscle becomes damaged from lack of oxygen and begins to die.
Types of Heart Attacks (Myocardial Infarctions)
Heart attacks are also known as myocardial infarctions (MI). Heart attacks come in two forms.
Non-ST segment elevation myocardial infarction (NSTEMI), or "non-Q-wave MI," does not cause typical changes on an electrocardiogram (ECG) test. But chemical markers in the blood show that damage has been done to the heart muscle.
ST segment elevation myocardial infarction (STEMI), or "Q-wave MI," is caused by a more prolonged period of blocked blood supply. It affects a larger area of the heart muscle and causes changes on the ECG as well as in chemical markers in the blood. Patients with ST segment elevation heart attacks have a worse prognosis, as these are more severe.
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Signs and Symptoms of a Heart Attack
Symptoms of a heart attack include:
- Crushing pressure in your chest
- Pain in your shoulder or arm
- Shortness of breath
Some heart attacks are obvious — sudden, intense, crushing chest pain. But many are not so obvious. A heart attack may occur with less intense symptoms, such as:
- Chest discomfort: Most heart attacks involve discomfort in the center of the chest lasting more than a few minutes, or that goes away and returns. It can feel like uncomfortable pressure, squeezing, fullness or pain.
- Upper body discomfort: This can include pain or discomfort in one or both arms, the back, neck, jaw or stomach.
- Shortness of breath: May occur with or without chest discomfort.
- Heart palpitations
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Risk Factors for Heart Attacks
There is a long list of traits, conditions and habits that can raise your risk of developing coronary artery disease (CAD). The more you have, the greater your risk. Fortunately, many of these can be controlled, helping to prevent or delay the development of CAD. These risk factors include:
- Smoking: Nicotine constricts your blood vessels, and other toxins can damage their inner lining, causing plaques to rupture and create a heart attack. Smoking can also raise cholesterol and blood pressure. Smoking reduces the amount of oxygen getting your body's tissues, and stopping smoking can reduce your risk of heart attack by 50 percent.
- High cholesterol: Elevated levels of low-density lipoprotein (LDL) or "bad" cholesterol and/or low levels of high-density lipoprotein (HDL) or "good" cholesterol can increase the risk of heart disease.
- High blood pressure: Uncontrolled blood pressure can help harden and thicken the arteries. In general, your blood pressure should be less than 120/80.
- Diabetes: Diabetes substantially increases your risk of developing coronary artery disease. Even when glucose (blood sugar) levels are under control, diabetes boosts the risk of heart disease, but the risks are even higher if blood sugar is not well controlled. About three-quarters of people with diabetes die of some form of heart or blood vessel disease. If you have diabetes, you should work with your doctor to manage it as best you can.
- Obesity: Your body mass index (BMI) should be under 25.
- Inactivity: You should exercise three times per week.
- Stress: Activities designed to manage stress may reduce your risk of CAD.
- Family history: A family history of heart disease increases your risk of developing CAD. Your risk increases if your father or brother was diagnosed with CAD before the age of 55 or if your mother was diagnosed before age 65.
- Age: Your risk for CAD increases with age. For men, the risk increases sharply after age 45. For women, the risk jumps after age 55.
- Metabolic syndrome: A collection of conditions that includes high blood pressure, high triglycerides, elevated insulin levels and excess body fat around the waist.
- Sleep Apnea: A condition in which your breathing stops or gets very shallow while you are sleeping.
- High Levels of C-Reactive Protein: Emerging research suggests that high levels of a protein called CRP in the blood may raise the risk of developing CAD or having a heart attack.
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Causes of Coronary Artery Disease
Disease Begins Early
Coronary artery disease begins in your teens. The walls of your coronary arteries are like hollow tubes. They start out smooth and elastic.
By the time you are in your teens, they begin to show traces of fat in them. Over time, the fat builds up, causing injury to the walls. Risk factors such as those listed above make matters worse.
In a bid to heal itself, your body's cells release chemicals that make the walls sticky. Substances traveling through your blood vessels — inflammatory cells, proteins, calcium and more — begin to stick to the walls. They combine with fat and form plaque. This clogging substance causes the arteries to narrow.
In some cases, blood platelets, which are designed to help clotting, come to the area and form blood clots. These clots may also block blood flow to the heart.
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Diagnosing a Heart Attack
If you are having a heart attack or suspect you are having one, your diagnosis likely will take place in an emergency room. You will have your blood pressure, pulse and temperature checked and will be asked about your symptoms. Then you will be hooked up to a heart monitor and a number of tests will be conducted immediately.
These tests check for levels of certain fats, cholesterol, sugar and proteins called troponins in the blood that help determine if you have risk factors for coronary artery disease or if you are having a heart attack.
Electrocardiogram (EKG or ECG)
This is a painless, noninvasive test in which patches with electrodes are attached to your skin to measure electrical impulses produced by your heart.
These impulses are recorded as waves displayed on a monitor or printed out on graph paper. The test can reveal evidence of a previous heart attack or one that is in progress. Heart rhythm is also captured with an EKG.
This test uses sound waves to create a moving picture of your heart.
- Provides information about the size and shape of your heart and how well your heart chambers and valves are functioning.
- Identifies areas of poor blood flow to the heart, areas of heart muscle that aren't contracting normally, and previous injury to the heart muscle caused by poor blood flow.
The test is noninvasive and is performed by placing a probe on your chest wall. It is the same technique used in sonograms in pregnant women.
Coronary Angiogram or Catheterization
To directly see the pattern of blood flow in your arteries, your doctor may want to perform a coronary catheterization. This involves injecting a dye into your arteries in what is called an angiogram.
The dye is delivered through a long, thin, flexible tube called a catheter that is threaded through a leg artery into the coronary arteries. This is called catheterization.
The dye outlines areas of blockages on x-ray images. If a blockage is found and needs treatment, a balloon can be pushed through the catheter and inflated to open the artery or arteries in question. A stent or tiny wire mesh tube can then be inserted to keep the artery open.
This procedure is done in the hospital.
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In some cases, coronary artery disease can be managed with lifestyle changes that include reducing risk factors. These include:
- Quitting smoking
- Modifying your diet
- Keeping your blood pressure under control
- Exercising (check with your doctor before beginning any exercise program)
- Reducing stress
If lifestyle changes aren't enough to control your coronary artery disease, you may need to take one or more medications to help your heart and arteries function better so that you receive sufficient oxygen-rich blood. These include:
- Cholesterol-lowering drugs: These drugs, often called statins, can decrease the amount of cholesterol in the blood, especially LDL or "bad" cholesterol. The drugs can also increase the amount of HDl or "good" cholesterol. The drugs can reduce the deposits that clog coronary arteries.
- Aspirin: Your doctor may recommend you take a daily aspirin tablet or other blood thinner to help reduce the tendency for your blood to clot.
- Beta-blockers: These are drugs that slow your heart rate and lower your blood pressure, reducing your heart's demand for oxygen.
- Nitroglycerin: This medication is taken during an angina attack, usually in the form of a tablet placed under your tongue. The drugs control chest pain by opening up the coronary arteries.
Angioplasty and Stenting
If you have a severe blockage in one or more arteries, you may benefit from a procedure known as angioplasty or percutaneous coronary intervention or revascularization (PCI).
An angioplasty can:
- Improve blood flow to your heart
- Relieve chest pain
- May be able to prevent a heart attack
An angioplasty opens blocked or narrowed coronary arteries. During angioplasty, a thin tube with a balloon on the end is threaded through a blood vessel to the narrowed or blocked coronary artery. Once in place, the balloon is inflated to push the plaque that is blocking your artery against the artery wall. This widens the artery and restores the flow of blood. A thin wire mesh tube called a stent may be placed in the artery permanently to keep the artery open. Some stents are coated with medication to help keep the artery open.
An angioplasty is done in the hospital and can take from 30 minutes to three hours. It is done under local anesthesia to numb the area of the groin where the catheter is inserted. Afterwards, you must remain in bed for at least another six hours. You may be able to go home the same day, but more often you will need to spend the night in the hospital.
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Coronary Artery Bypass Graft (CABG) Surgery
In coronary artery bypass graft (CABG) surgery, arteries or veins from other areas in your body are used to bypass or go around your narrowed coronary arteries. CABG can improve blood flow to the heart, relieve pain and possibly prevent a heart attack. A CABG is open-heart surgery. As a result, it is often used in cases where multiple coronary arteries are blocked or where the blockages are not suitable for angioplasty or stenting.
About CABG Surgery
CABG surgery involves exposing the heart through either the breastbone or the ribs. The operation typically includes the use of a heart-lung machine, which takes blood from the heart, adds oxygen, and then pumps it back into the body. Your surgeon may take an artery from the chest wall or remove a section of vein from your leg. These vessels are then grafted to the blocked arteries above and below the blocked areas. After the grafts are sewn into place, the heart-lung machine is turned off. The breastbone is wired together and the chest is closed. You are under general anesthesia during the operation. The CABG operation takes four to five hours.
Afterwards, you will be taken to the ICU where you will be on a heart monitor, have a breathing tube in your mouth, and a catheter in your bladder. You will also have temporary pacing wires and drainage tubes in your chest, and have several intravenous catheters in your neck and arms. You will probably remain in the hospital for four to five days and should be able to return to office-type work in four to six weeks. Because the bypass arteries can also clog, you must pay close attention to your diet, take aspirin and other medications as prescribed by your doctor, exercise regularly and maintain a healthy lifestyle to keep this from happening.
Off-Pump Beating-Heart CABG Surgery
In some cases, your surgeon may want to perform your bypass while your heart is still beating. This operation uses special equipment to stabilize or quiet the heart down while the surgery is ongoing. The heart-lung machine is not used. The remaining details of the surgery are the same as conventional CABG. The goal of off-pump bypass surgery is to decrease the risks associated with the use of the heart lung machine, such as stroke, renal failure and need for blood transfusion. Not everybody is a candidate for off-pump CABG.
Endoscopic or Minimally Invasive CABG Surgery
Traditional CABG surgery — with or without the use of a heart-lung machine — requires a large incision dividing the breastbone. In endoscopic CABG surgery, your surgeon performs the bypass through a smaller incision or incisions, using a tiny endoscopic camera and smaller instruments. Also, the heart-lung machine is not used The operation is associated with less post-operative pain, a shorter hospital stay and a shorter recuperation. Not everybody is a candidate for endoscopic CABG. In most cases, it is reserved for those who need just one blocked artery bypassed.
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