What is a heart attack?

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What is a heart attack?

Follow the jump links below to learn more about the signs and treatment of a heart attack:

Overview
Risk Factors
Signs and Symptoms
When to Seek Medical Attention
Screening and Diagnostic Tests
Complications
Prescription Medications for Initial Treatment
Surgical and Other Procedures

Overview
The heart muscle requires a constant supply of oxygen-rich blood to nourish it. The coronary arteries (large blood vessels that transport blood to the heart muscle) provide the heart with this critical blood supply. If you have coronary artery disease, those arteries become narrow and blood cannot flow as well as it should.

Fatty matter, calcium, proteins, and inflammatory cells build up within the arteries to form plaques of different sizes. The plaque deposits are hard on the outside, and can be soft and mushy on the inside.

A heart attack is damage to the heart muscle because of a loss of, or inadequate supply of blood to the heart. The affected area of the heart becomes starved for oxygen and if it continues long enough, cells in the affected area die.

Over time, fatty deposits, and plaque build up in the lining of the arteries blocking the natural path of blood flow. As the artery narrows, the risk increases that a clot will form and totally block blood flow. If a clot blocks the flow of blood through a coronary artery it interrupts the blood supply to your heart and can injure or destroy part of the heart muscle and can be deadly. The amount of damage to the heart muscle depends on the size of the area supplied by the blocked artery and the time between injury and treatment.

The heart’s pumping ability is lessened after a heart attack followed with conventional treatment – because as the tissue heals new scar tissue is created in the damaged area and does not contract or pump as well as healthy heart muscle tissue.

The medical term for a heart attack is myocardial infarction. Myo refers to “muscle”; cardio refers to “heart”; infarct refers to “death of tissue from lack of oxygen.” All muscles, including the heart, need a constant supply of blood, without it the tissue becomes damaged and begins to die. Without a steady supply of blood, heart cells are injured, causing pain or pressure. If blood flow is not restored, heart cells begin to die and scar tissue begins to form. If a large area of the heart muscle is damaged, a heart attack can be fatal.

Risk Factors
Coronary artery disease is a principal underlying cause of heart attacks. Factors that increase your risk of narrowed coronary arteries and consequently, a heart attack include:

  • High blood pressure
  • Smoking
  • Obesity
  • Physical inactivity
  • Diabetes
  • Stress
  • Alcohol
  • Heredity
  • Gender
  • A family history of heart disease
  • A high level of low-density lipoprotein (LDL) cholesterol (the “bad” cholesterol)
  • If you are a woman, your risks increase sometime after menopause
  • If your father or brother had heart disease before age 55 or your mother or sister had heart trouble BEFORE 65, your risk of developing heart disease increases

A heart attack can also occur when a blood clot from inside a diseased heart breaks away and lodges in an otherwise healthy, or a narrowed coronary artery.

A heart attack is not a fixed one-time incident; it is a process on average developing over several hours. Time is of the essence, as with each passing minute, heart tissue is deprived of oxygen carrying blood and deteriorates or dies. If blood flow can be restored in time, damage to the heart can be limited or prevented to a degree.

Signs and Symptoms
Heart attacks have numerous unpredictable signs and symptoms. Not all people who have heart attacks experience the same symptoms or to the same degree. Heart attacks are not as theatrical and dramatic as the ones you see on TV. Heart attack symptoms in women, in older adults and in people with diabetes tend to be less pronounced. Some people have no symptoms at all. Still, the more signs and symptoms you have, the higher the likelihood that you may be having a heart attack.
Warning signs and symptoms of a heart attack include:

  • Pressure, fullness or a squeezing pain in the center of your chest that lasts for more than a few minutes
  • Pain extending beyond your chest to your shoulder, arm, back, or even to your teeth and jaw
  • Increasing episodes of chest pain
  • Prolonged pain in upper abdomen
  • Shortness of breath
  • Sweating
  • Impending sense of doom
  • Lightheadedness
  • Fainting
  • Nausea and vomiting

A heart attack typically happens unexpectedly. It can occur anytime, anywhere, at work or play, while resting, or while in motion. Some people who have a heart attack dismiss the warning signs and symptoms because they can happen hours, days, or weeks in advance. The earliest predictor of an attack may be recurrent chest pain (angina), triggered by exertion and relieved by rest. Angina is caused by temporary, insufficient blood flow to the heart. The medical term for insufficient blood flow to the heart is cardiac ischemia.

When to Seek Medical Attention
During a heart attack, people waste valuable time because they don’t recognize the important signs and symptoms or they deny them. People also hesitate calling for help because they are afraid of embarrassment if it is a false alarm. If you think you may be suffering a heart attack get help immediately.

One of the most important things you can do to survive a heart attack is to recognize what’s happening and to take immediate action. Of the people who die of heart attacks, most die within the first hour after the onset of signs and symptoms. Don’t waste time — minutes are precious and can be a matter of life or death!

Seek emergency medical treatment if you think you or another person may be experiencing a heart attack. An ambulance crew can begin treatment, and the sooner you get to a hospital, the more can be done to limit the amount of damage done to your heart during a heart attack. Fast action could save your life.

If it turns out you weren’t having a heart attack, doctors may be able to pinpoint the cause of your symptoms and treat them.

Screening and Diagnostic Tests
If you’re having a heart attack or suspect you’re having one, screening and diagnosis will happen in an emergency room. At the hospital, you will probably be asked to describe your symptoms and will have your blood pressure, pulse, and temperature checked. The doctor will listen to your heart and lungs with a stethoscope. You will be asked for your health history and if there is a history of heart problems in your family. In an effort to determine if you are having a heart attack, doctors may also conduct tests to determine if your signs and symptoms are a heart attack or a different condition. These tests may include:

    • Electrocardiogram (ECG). This is often the first test done to diagnose a heart attack. This test records the electrical activity of your heart via electrodes attached to your skin. Impulses are recorded as “waves” displayed on a monitor or printed on paper. Because injured heart muscle doesn’t conduct electrical impulses normally, the ECG may show that a heart attack has occurred or is in progress.
    • Blood tests. Certain heart enzymes slowly leak out into your blood if your heart has been damaged by a heart attack. Emergency room doctors may take samples of your blood to test for the presence of these enzymes. If you’ve had a heart attack or one is occurring, doctors will take immediate steps to treat your condition. You may also undergo these additional tests:
    • Chest X-ray. An X-ray image of your chest allows your doctor to check the size and shape of your heart and its blood vessels.
    • Nuclear scan. This test helps identify blood flow problems to your heart. Trace amounts of radioactive material, such as thallium, are injected into your bloodstream. Special cameras can detect the radioactive material as it flows through your heart and lungs. Areas of blockage in arteries — through which less of the radioactive material flows — appear as dark spots on the scan.
    • Echocardiogram. This test uses sound waves to produce an image of your heart. During an echocardiogram, sound waves are directed at your heart from a transducer, a wand-like device, held on your chest. The sound waves bounce off your heart and are reflected back through your chest wall and processed electronically to provide video images of your heart. An echocardiogram can help identify whether an area of your heart has been damaged by a heart attack and isn’t pumping normally or at peak capacity.

  • Coronary catheterization (angiogram). This test can show if your coronary arteries are narrowed or blocked. A liquid dye is injected into the arteries of your heart through a long, thin tube (catheter) that’s fed through an artery, usually in your leg, to arteries in your heart. As the dye fills your arteries, the arteries become visible on X-ray and videotape, revealing areas of blockage. Additionally, while the catheter is in position, it can be used to treat the blockage. This procedure is called angioplasty.

Complications
A heart attack can occur without recognized pain and discomfort, and it can cause death. Complications are often related to the damage sustained by your heart during a heart attack. This damage can lead to:

  • Abnormal heart rhythms (arrhythmias). If your heart muscle is damaged from a heart attack, electrical “short circuits” can develop resulting in abnormal heart rhythms, some of which can be serious, even fatal.
  • Congestive heart failure. The amount of damaged tissue in your heart may be so extensive that the remaining heart muscle can’t do an adequate job of pumping blood out of your heart. This decreases blood flow to tissues and organs throughout your body, producing shortness of breath, fatigue, and swelling in your ankles and feet. Congestive heart failure may be a temporary problem that remedies itself after your heart, which has been stunned by a heart attack, recovers over a few days to weeks. However, it can also be a chronic condition resulting from extensive and permanent damage to your heart following your heart attack.

With each passing minute after a heart attack, more tissue is deprived of oxygen and deteriorates or dies. The main way to prevent continuing damage is to restore a healthy blood flow quickly.

Prescription Medication for Initial Treatment
Initial treatment of a heart attack in the emergency room may also involve prescription medications, typically given through a vein in your arm (intravenously), such as:

    • Thrombolytics. These drugs, also called clot-busters, help dissolve a blood clot that’s blocking a coronary artery and blood flow to your heart.
    • Drugs. Doctors in the emergency room may give you a thrombolytic drug along with a second drug called a platelet IIb/IIIa receptor blocker. The second drug helps prevent new clots from forming.
    • Other blood-thinning medications. Drugs, such as heparin, like aspirins, make your blood less “sticky” and less likely to form more dangerous clots.
    • Pain relievers. If your chest pain or associated pain is great, you may receive a pain reliever such as morphine to relieve your discomfort.
    • Nitroglycerine. This medication, used to treat chest pain (angina), temporarily opens narrowed blood vessels, improving blood flow to and from your heart.
    • Beta blockers. These medications help relax your heart muscle, slow your heartbeat and decrease blood pressure, making your heart’s job easier.

  • Cholesterol-lowering medications. Examples include statins, niacin, fibrates and bile acid sequestrants. These drugs help lower levels of unwanted blood cholesterol and may be helpful if given soon after a heart attack to improve survival.

Surgical and other procedures
In addition to medications, you may undergo one of the following procedures to treat your heart attack:

  • Coronary angioplasty. Emergency angioplasty opens blocked coronary arteries, letting blood flow more freely to your heart. Doctors insert a long, thin tube (catheter) that’s passed through an artery, usually in your leg, to a blocked artery in your heart. This catheter is equipped with a special balloon tip. Once in position, the balloon tip is briefly inflated to open up a blocked coronary artery. At the same time, a metal mesh (stent) may be inserted into the artery to keep it open long-term, restoring blood flow to the heart. Coronary angioplasty may be done at the same time as a coronary catheterization (angiogram), a procedure that doctors do first to locate narrowed arteries to the heart.

Surviving a heart attack doesn’t mean that life, as you know it, is over. On the contrary, many people can lead full, active lives after a heart attack. TherOx is dedicated to finding a way to give heart attack patients the chance to be able to live happy, healthy, normal lives after a heart attack.



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