Q. What Is Heart Disease?
Diseases That Affect the Heart and Cardiovascular System
Q. What Happens During a Heart Attack?
The heart muscle requires a constant supply of oxygen-rich blood to nourish it. The coronary arteries 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 soft and mushy on the inside.
When the plaque's hard, outer shell cracks (plaque rupture), platelets (disc-shaped particles in the blood that aid clotting) come to the area, and blood clots form around the plaque. If a blood clot totally blocks the artery, the heart muscle becomes "starved" for oxygen. Within a short time, death of heart muscle cells occurs, causing permanent damage. This is called a myocardial infarction (MI), or heart attack.
While it is unusual, a heart attack can also be caused by a spasm of a coronary artery. During coronary spasm, the coronary arteries restrict or spasm on and off, reducing blood supply to the heart muscle (ischemia). It may occur at rest and can even occur in people without significant coronary artery disease.
Each coronary artery supplies blood to a region of heart muscle. 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.
Healing of the heart muscle begins soon after a heart attack and takes about eight weeks. Just like a skin wound, the heart's wound heals and a scar will form in the damaged area. But, the new scar tissue does not contract or pump as well as healthy heart muscle tissue. So, the heart's pumping ability is lessened after a heart attack. The amount of lost pumping ability depends on the size and location of the scar.
Q. What are the Symptoms of a Heart Attack ?
Symptoms of a heart attack include:
- Discomfort, pressure, heaviness, or pain in the chest, arm or below the breastbone
- Discomfort radiating to the back, jaw, throat or arm
- Fullness, indigestion or choking feeling (may feel like heartburn)
- Sweating, nausea, vomiting or dizziness
- Extreme weakness, anxiety or shortness of breath
- Rapid or irregular heartbeats
During a heart attack, symptoms last 30 minutes or longer and are not relieved by rest or oral medications (medications taken by mouth).
Some people have a heart attack without having any symptoms (a "silent" myocardial infarction). A silent MI can occur in any person, though it is more common among diabetics.
Q. What Do I Do if I Have a Heart Attack?
Quick treatment to open the blocked artery is essential to lessen the amount of damage. At the first signs of a heart attack, call for emergency treatment (usually 911). The best time to treat a heart attack is within one to two hours of the first onset of symptoms. Waiting longer than that increases the damage to your heart and reduces your chance of survival.
Keep in mind that chest discomfort can be described many ways. It can occur in the chest or in the arms, back or jaw. If you have symptoms, take notice. These are your heart disease warning signs. Seek medical care immediately.
Q. How Is a Heart Attack Diagnosed?
Once the emergency care team arrives, they will ask you about your symptoms and begin to evaluate you. The diagnosis of the heart attack is based on your symptoms, ECG and the results of your blood tests. The goal of treatment is to treat you quickly and limit heart muscle damage.
Tests You Take
The ECG (also known as EKG or electrocardiogram) can tell how much damage has occurred to your heart muscle and where it has occurred. In addition, your heart rate and rhythm can be monitored.
Blood may be drawn to measure levels of cardiac enzymes in the blood that indicate heart muscle damage. These enzymes are normally found inside the cells of your heart and are needed for their function. When your heart muscle cells are injured, their contents -- including the enzymes -- are released into your bloodstream. By measuring the levels of these enzymes, the doctor can determine the size of the heart attack and approximately when the heart attack started. Troponin levels will also be measured. Troponins are proteins found inside of heart cells that are released when they are damaged by ischemia. Troponins can detect very small heart attacks as well as those that occurred more than a day after symptoms ensued.
Echocardiography is an imaging test that can be used during and after a heart attack to learn how the heart is pumping and what areas are not pumping normally. The "echo" can also tell if any structures of the heart (valves, septum, etc.) have been injured during the heart attack.
Cardiac catheterization, also called cardiac cath, may be used during the first hours of a heart attack if medications are not relieving the ischemia or symptoms. The cardiac cath can be used to directly visualize the blocked artery and help your doctor determine which procedure is needed to treat the blockage.
Q. How Is a Heart Attack Treated?
Once heart attack is diagnosed, treatment begins immediately -- possibly in the ambulance or emergency room. Medications and surgical procedures are used to treat a heart attack.
Q. What Medications Are Used to Treat a Heart Attack?
The goals of medication therapy are to break up or prevent blood clots, prevent platelets from gathering and sticking to the plaque, stabilize the plaque and prevent further ischemia.
These medications must be given as soon as possible (within one to two hours from the start of your heart attack) to decrease the amount of heart damage. The longer the delay in starting these drugs, the more damage can occur and the less benefit they can provide.
Medications for This Purpose May Include:
- Aspirin to prevent blood clotting that may worsen the heart attack.
- Antiplatelets to prevent blood clotting.
- Thrombolytic therapy ("clot busters") to dissolve any blood clots that are present in the heart's arteries.
- Any combination of the above
- Other drugs, given during or after a heart attack, lessen your heart's work, improve the functioning of the heart, widen or dilate your blood vessels, decrease your pain and guard against any life-threatening heart rhythms.
Q. What Is Atrial Fibrillation?
Atrial fibrillation (AF) is the most common type of irregular heartbeat. If you have AF, the impulse does not travel in an orderly fashion through the atria. Instead, many impulses begin and spread through the atria and compete for a chance to travel through the AV node. The impulses originate from tissues other than the heart's electrical system.
The firing of these impulses results in a very rapid and disorganized heartbeat. The rate of impulses through the atria can range from 300 to 600 beats per minute. Luckily, the AV node limits the number of impulses it allows to travel to the ventricles. As a result, the pulse rate is often less than 150 beats per minute, but this is often fast enough to cause symptoms.
Q. What Are the Symptoms of Atrial Fibrillation?
Most people with AF experience one or more of the following symptoms:
- Heart palpitations (a sudden pounding, fluttering, or racing feeling in the heart).
- Lack of energy; tired.
- Dizziness (feeling faint or light-headed).
- Chest discomfort (pain, pressure, or discomfort in the chest).
- Shortness of breath (difficulty breathing during activities of daily living).
Q. What Causes Atrial Fibrillation?
- Atrial fibrillation is associated with many conditions, including:
- High blood pressure.
- Coronary artery disease (hardening of the heart arteries).
- Having undergoing heart surgery.
- Chronic lung disease.
- Heart failure.
- Cardiomyopathy (disease of heart muscle that causes heart failure).
- Congenital (present at birth) heart disease.
- Pulmonary embolism (blood clot in lungs).
- Hyperthyroidism (overactive thyroid, uncommon).
- Pericarditis (inflammation of the outside lining of the heart, uncommon).
In at least 10% of people with AF, no underlying heart disease is found. In these people, AF may be related to alcohol or excessive caffeine use, stress, certain drugs, metabolic imbalances or severe infections. In some people, no identifiable cause can be found.
The risk of AF increases with age, particularly after 60 years of age.
Q. Why Is Atrial Fibrillation Dangerous?
Many people live for years with atrial fibrillation without problems. However, because the atria are beating rapidly and irregularly, blood does not flow through them as quickly. This makes the blood more likely to clot. If the clot is pumped out of the heart, it can travel to the brain, resulting in a stroke. The likelihood of a stroke in people with AF is 5 times higher than in the general population. Although about half of all blood clots related to AF result in stroke, clots can travel to other parts of the body (kidney, heart, intestines) causing problems.
AF can also decrease the heart's pumping ability by as much as 20%-30%. AF combined with a fast heart rate over a long period of time, can result in heart failure.
Q. How Is Atrial Fibrillation Diagnosed?
Four tests are used to diagnose atrial fibrillation, including:
- Holter monitor
- Event monitor
- Transtelephonic monitor
These monitoring devices help your doctor learn if you are having irregular heartbeats, what kind they are, how long they last, and what may be causing them.
Q. How Are Medications Used to Treat Atrial Fibrillation?
Medications are prescribed in the management of AF depending on the overall treatment goal. If the goal is to restore normal heart rhythm, a type of drug called an antiarrhythmic is prescribed. If it's not possible to achieve this goal, doctors will try to manage your disease by slowing down the heart rate. In both cases, your doctor will give you medications called anticoagulants to decrease blood clot formation.
Restore Normal Heart Rhythm
Many medications are available to restore and maintain a normal heart rhythm, including Quinidex (quinidine), Pronestyl (procainimide), Norpace (disopyramine), Toprol, Lopressor, Tambocor, Rythmol (propafenone), Betapace (sotalol), Tikosyn, and Cordarone. You may have to stay in the hospital when you first start using these drugs so that your heart rhythm can be carefully monitored. These medications are effective 30%-60% of the time, but may lose their effectiveness over time. Many have potentially serious side effects, so you may need to try several medications to find the best one for you.
Heart Rate Control
Control of the heart rate can be obtained using Lanoxin (digoxin), or two other groups of medications that lower heart rate, called beta-blockers, and calcium channel blockers.
Blood Thinners or Anticoagulation Drugs
Coumadin (warfarin) reduces the risk of stroke by 60%-80% in people with AF. When Coumadin is used, regular blood tests are required to assure that the blood is thinned at a safe and effective level. Some people may be treated with aspirin instead of Coumadin.
When medications do not work to correct or control AF, a procedure may be necessary.
Source: WebMd Health
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