Jumat, 14 Desember 2007

What is Coronary Artery Bypass Surgery?

This is a type of heart surgery. It's sometimes called CABG ("cabbage"). The surgery reroutes, or "bypasses," blood around clogged arteries to improve blood flow and oxygen to the heart.

The arteries that bring blood to the heart muscle (coronary arteries) can become clogged by plaque (a buildup of fat, cholesterol plus other substances). This can then slow or stop blood flow through the heart's blood vessels, leading to chest pain or a heart attack. Increasing blood flow to the heart muscle can relieve chest pain and also reduce the risk of heart attack.

Surgeons take a segment of a healthy blood vessel from another part of the body, and then make a detour around the blocked part of the coronary artery. An artery may be detached from the chest wall and the open end attached to the coronary artery below the blocked area. Or a piece of a long vein in your leg may be taken. One end is sewn onto the large artery leaving your heart - the aorta. The other end of the vein is attached or "grafted" to the coronary artery below the blocked area.

Either way, blood can then utilize use this new path to flow freely to the heart muscle.
A patient may undergo one, two, three or more bypass grafts, depending on how many coronary arteries are blocked.

Cardiopulmonary bypass with a pump oxygenator (heart-lung machine) is used for most coronary bypass graft operations. This means that besides the surgeon, a team made up of a cardiac anesthesiologist and surgical nurse, a competent perfusionist (blood flow specialist) are required.

What happens after bypass surgery?
After surgery, the patient is moved to a hospital bed in the cardiac surgical intensive care unit. Heart rate and blood pressure monitoring devices continuously monitor the patient for 12 to 24 hours.

Vulnerable Plaque in Heart Disease

Swelling (inflammation) is the body's natural reaction to an injury. Inflammation can happen anywhere on the skin, within the body, and even inside the arteries. Scientists are now learning inflammation may play a part in many of the diseases that come with aging, including coronary artery disease.

For many years, doctors have thought that the main cause of a heart attack or stroke or was the buildup of fatty plaque within an artery, leading to the heart or brain. In time, the plaque buildup would narrow the artery so much, that the artery would close off or become clogged by a blood clot. The lack of oxygen-rich blood to the heart would then lead to a heart attack. However these types of blockages cause only about 3 out of 10 heart attacks.

Researchers are finding people who that heart attacks do not have arteries severely narrowed by plaque! Vulnerable plaque may be buried inside the artery wall, and not bulge out and block the blood flow through the artery. This is why researchers began to look at how inflammation affects the arteries, and to see if inflammation could lead to a heart attack.

What they found was that inflammation leads to the development of "soft" or vulnerable plaque. They also found that vulnerable plaque was more than just debris, clogging an artery, that it was filled with different cell types that help with blood clotting.

When this inflammation is combined with other stresses, like high blood pressure, it can cause the thin covering over the plaque to crack and bleed, spilling the entire contents of the vulnerable plaque into the bloodstream. The sticky cytokines on the artery wall capture blood cells (mainly platelets) that rush to the site of injury. When these cells clump together, they can form a clot large enough to block the artery

Sudden Cardiac Death

Sudden cardiac death (sudden arrest) is death resulting from an sudden loss of heart function (cardiac arrest). The victim may or may not have diagnosed heart disease. The time and mode of death are unexpected. It occurs within moments after symptoms appear. The most common reason for patients to die suddenly from cardiac arrest is coronary heart disease (fatty buildups in the arteries that supply blood to the heart muscle).

All known heart diseases can lead to cardiac arrest or sudden cardiac death. Most of the cardiac arrests that lead to sudden death occur when the electrical impulses in the diseased heart become rapid (ventricular tachycardia), chaotic (ventricular fibrillation) or both. This irregular heart rhythm (arrhythmia) causes the heart to suddenly stop beating. Some cardiac arrests are due to extreme slowing of the heart. This is called bradycardia. Bradycardia is common in premature infants.

In 90 percent of adult victims of sudden cardiac death, two or more major coronary arteries are narrowed by fatty buildups. Scarring from a prior heart attack is found in two-thirds of victims. When sudden death occurs in young adults, other heart abnormalities are more likely causes. Adrenaline released during intense physical or athletic activity often acts as a trigger for sudden death when these abnormalities are present. Under certain conditions, various heart medications and other drugs — as well as illegal drug abuse — can lead to abnormal heart rhythms that cause sudden death.

The term "massive heart attack" is often wrongly used in the media to describe sudden death. The term "heart attack" refers to death of heart muscle tissue due to the loss of blood supply, not necessarily resulting in a cardiac arrest or the death of the heart attack victim. A heart attack may cause cardiac arrest and sudden cardiac death, but the terms aren't synonymous.

Prognosis and Treatment of Abnormal Heartbeats

Most arrhythmias (abnormal heartbeats) neither cause symptoms nor interfere with the heart's ability to pump blood. Thus, they usually pose little or no risk. They can cause considerable anxiety if a person becomes aware of them. There are some arrhythmias, harmless in themselves that can lead to more serious arrhythmias.

Any arrhythmia that impairs the heart's ability to pump blood adequately is serious. How serious, depends in part on where the arrhythmia originates. Is it in the heart's normal pacemaker, in the atria, or in the ventricles? Generally, arrhythmias which originate in the ventricles are more serious than those that originate in the atria. These are more serious than those that originate in the pacemaker. However, there are many exceptions.

For people who have a harmless, yet worrisome arrhythmia, reassurance that the arrhythmia is harmless may be treatment enough. Sometimes arrhythmias occur less often or even stop, when doctors change a person's drugs or adjust the dosages. Avoiding alcohol, caffeine, smoking, or strenuous exercise can also help.

Antiarrhythmic drugs are useful for suppressing fast arrhythmias that cause intolerable symptoms or pose a risk. No single drug cures all arrhythmias in people. Sometimes several drugs must be tried until the response is satisfactory. Sometimes antiarrhythmic drugs can worsen or even cause arrhythmias; this effect is called proarrhythmia. Antiarrhythmic drugs can also produce other side effects.

Artificial pacemakers are electronic devices that act in place of the heart's own pacemaker. These devices are implanted surgically under the skin, usually below the left or right collarbone. They are connected to the heart by wires running inside a vein. New circuitry has almost completely eliminated the risk of interference from automobile distributors, radar, microwaves, and airport security detectors.

Any abnormality within the chest is wise to get checked out by your family doctor.

Silent Ischemia and Ischemic Heart Disease

Ischemia is a condition in which the blood flow (and thus oxygen) is restricted to a part of the body. Cardiac ischemia is the name for lack of blood flow and oxygen to the heart muscle.

What is ischemic heart disease? It is the term given to heart problems caused by narrowed heart arteries. When arteries are narrowed, less blood and oxygen reach the heart muscle. This is also called coronary artery disease (CAD) and coronary heart disease. This can ultimately lead to heart attack. Ischemia often causes chest pain or discomfort known as angina pectoris.

What is silent ischemia?
People who experience ischemia without pain have a heart condition known as silent ischemia. They may have a heart attack with no prior warning. People with angina also may have undiagnosed episodes of silent ischemia. An exercise test or 24-hour portable monitors of the electrocardiogram (Holter monitor) are two tests often used to diagnose this problem. Other tests also may be use

Cardiac ischemia refers to lack of blood flow and oxygen to the heart muscle. Cardiac ischemia happens when an artery becomes narrowed or blocked for a short time, preventing oxygen-rich blood from reaching the heart. If ischemia is severe or lasts too long, it can cause a heart attack (myocardial infarction) and can lead to heart tissue death. In most cases, a temporary blood shortage to the heart causes the pain of angina pectoris.

Silent ischemia may also disturb the heart's rhythm. Abnormal rhythms such as
ventricular tachycardia or ventricular fibrillation may interfere with the heart's pumping ability and can even cause fainting or sudden cardiac death.

Silent ischemia has no symptoms. Researchers have found that if you have episodes of noticeable chest pain, you may also have episodes of silent ischemia.

Sick Sinus Syndrome in Heart Disease

Any irregularity in your heart's natural rhythm is called an arrhythmia. Almost everyone's heart skips a beat now and again, and these mild palpitations are usually harmless.

Electrical impulses from the heart muscle (the myocardium) cause the heart to beat (contract). This electrical signal begins in the Sinoatrial Node, also called the SA node or the sinus node. The SA node is located at the top of the heart's upper-right chamber (the right atrium). The SA node is sometimes called the heart's "natural pacemaker." When an electrical impulse is released from the SA node, it causes the heart's upper chambers to contract.

Sick sinus syndrome is a type of arrhythmia. These are a group of signs and symptoms that tells doctors the SA node is not working properly. The SA node usually sends electrical impulses at a certain rate, but if the SA node is not working properly, the heart may beat too fast, too slow, or both.

Sick sinus syndrome usually develops slowly over many years, and the causes are not always known. It occurs more often in people over fifty, and children might develop the condition after having open heart surgery.

Many people with sick sinus syndrome do not have symptoms. Or they do not think their symptoms are serious enough for them to see a doctor. Some signs and symptoms of sick sinus syndrome are fainting, being dizzy, confusion that comes and goes, feeling the hear has skipped a beat (palpitations), chest pain, angina, fatigue, shortness of breathe aching muscles.

Sick sinus syndrome can be hard to diagnose as the patient may not have many of the symptoms. The doctor will take a medical history, ask about symptoms, and listen to the heart with a stethoscope. With the stethoscope, the doctor may be able to hear an irregular heartbeat, which can be a sign of sick sinus syndrome.

Rheumatic Fever and Heart Disease

Before antibiotic medicines became widely used, rheumatic fever was the largest cause of valve disease. Rheumatic fever is a condition that is a complication of untreated strep throat. Strep throat is caused by a group A streptococcal infection found in the throat.

Rheumatic fever can damage body tissues by causing them to swell, but its greatest danger lies in the damage it can do to your heart. More than half of the time, rheumatic fever leads to scarring of the heart's valves. This scarring can narrow the valve and make it harder for the valve to open properly or to close completely. In turn, your heart has to work harder to pump blood to the rest of your body. This valve damage can lead to a condition called rheumatic heart disease, which, in time, can lead to congestive heart failure.

Rheumatic fever is not an infection itself, rather the result of an untreated strep infection. When the body senses the strep infection, it sends antibodies to fight it. Sometimes, these antibodies attack the tissues of joints or the heart instead. If the antibodies attack the heart they can cause the heart valves to swell, which can lead to scarring of the valve "doors." (The doors are called leaflets.) The scarred leaflets make it harder for the valve to either open or close properly, or both.

The symptoms of rheumatic fever usually begin 1 to 6 weeks after a strep infection. The symptoms are fever, joint pain or swelling in your wrists, elbows, knees, or ankles. Small bumps under the skin over elbows or knees (called nodules). Maybe a small raised red rash on the chest, back, or stomach, experience stomach pain or feeling less hungry. Weakness, shortness of breath, or feeling very tired

Please remember that Rheumatic Fever needs immediate medical attention!