FOOD FOR THOUGHT

• by SMITTY
• 2008-08-20 06:08:26
• General Posting
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From TIME and CNN

Heart disease is often referred to as the leading cause of death in the U.S. — but in fact, nobody dies of heart disease, because there is no such thing. "Heart disease" is a catchall term that includes coronary artery disease, heart failure and cardiomyopathy (just as "lung disease" includes asthma, emphysema and lung cancer). It doesn't include heart attack, though, because a heart attack can be the result of one kind of heart disease or the cause of another — but isn't technically a disease itself.

If that sounds confusing, it's because the heart is only part, though obviously the most important part, of the cardiovascular system, which includes not only the heart itself but also the blood vessels that carry oxygen and nutrients to every corner of the body. And damage to one part of this interconnected system can affect other parts.

CAUSES

The heart sends blood throughout the body — including back to itself. When everything is working right, the blood that keeps it well nourished is delivered through the coronary arteries. But in one form of heart disease, called coronary artery disease (or CAD) those arteries aren't working properly. They become clogged with fatty deposits called plaques, made out of a type of cholesterol (low-density lipoprotein, also known as LDL or, more familiarly, "bad cholesterol"). A narrowed artery can't deliver as much nutrient-rich blood as the heart needs, which can lead to symptoms such as angina — chest pain.
Left untreated, the lack of blood can make the heart weaker over time. The resulting condition is known as heart failure, or congestive heart failure — a confusing name, because it doesn't mean the heart stops entirely. Even so, while heart failure doesn't necessarily kill right away, it can eventually lead to death: 300,000 or so Americans succumb to it every year. People who get heart transplants almost always need them because of heart failure.

Heart failure can come from other causes as well. Diabetes weakens the heart; so does smoking, and so does high blood pressure, which forces the heart to work harder than it's designed to do. Obesity does the same. Inflammation of the heart from those causes is collectively known as cardiomyopathy.

So the best way to avoid heart failure is to avoid obesity, avoid smoking, manage diabetes if you have it, eat a heart-healthy diet, manage blood pressure and get plenty of exercise, which help reduce the buildup of plaques, exercise the heart muscle, or both.

Another cause of heart failure is a heart attack, known to doctors as a myocardial infarction, or MI. This results from a complete blockage of one of the coronary arteries; the part of the heart nourished through that artery suddenly gets no nutrition at all, and the muscle begins to die. The blockage usually happens in an artery that's already narrowed by coronary artery disease. Either a bit of plaque breaks off (inflammation is believed to be one reason this happens) or a clot forms (plaques can also trigger clot formation), and the floating chunk lodges in the narrowed artery, forming a plug. (Aspirin reduces inflammation and helps keep clots from forming; that's why older people and people who have already had heart attacks are often told to take a baby aspirin every day, as a preventive). If the artery is already very narrow, it doesn't take much of a plug to close it off.

Depending on how much of the heart is deprived of blood and for how long, the damage from a heart attack might be insignificant, or it might lead to longer-term heart failure. But it also might result in ventricular fibrillation, in which the heart muscle begins fluttering instead of pumping. If the heart's normal pumping action isn't restored quickly, either through cardiopulmonary resuscitation (CPR) or the use of an electric defibrillator, death from cardiac arrest is likely. You don't need a heart attack to trigger fibrillation, either: Heart failure by itself can raise the risk of spontaneous fibrillation, as can high blood pressure, obesity and smoking.

TREATMENTS

In the aftermath of a heart attack, a patient may get an implanted pacemaker, which uses tiny jolts of electricity to guarantee a normal rhythm and prevent fibrillation from occurring again, or from happening in the first place.
Another frequent treatment for an ailing cardiovascular system — sometimes in the aftermath of a heart attack, sometimes beforehand, when narrowed arteries are detected through symptoms like angina — is to try and widen the coronary arteries. The less invasive way to do that is through balloon angioplasty, in which a tiny balloon is snaked into the coronary arteries and inflated, crushing plaque up against the arterial wall to let blood flow smoothly again. Sometimes, a stent — a little coil of metal — is inserted to keep the artery propped open indefinitely.

The more invasive cure for narrowed arteries: bypass surgery, in which a short length of vein is borrowed from somewhere else in the body (usually the leg) and stitched in to give blood a detour around the blocked segment. When people talk about double or triple or quadruple bypass surgery, that refers to the number of arteries that get new pieces.
While bypass surgery or angioplasty or a pacemaker are treatments for diseases of the heart, they're not cures. Unless a patient changes his or her eating habits, quits smoking, gets more exercise and takes medication, arteries can easily become blocked again with the same LDL deposits that clogged them in the first place. The most common medications: a widely prescribed class of drugs called statins, which include lovastatin (sold under the trade name Mevacor), simvastatin (Zocor), pravastatin (Pravachol), atorvastatin (Lipitor), fluvastatin (Lescol) and rosuvastatin (Crestor).
They're all chemically related, and all of them interfere with the production of LDL by the liver (they can also cause liver and muscle damage, which is why users have to take periodic blood tests). But there's evidence that statins also help prevent plaque buildup in other ways. They also seem to reduce inflammation, and drive down blood levels of another heart-risky fat called triglycerides. That may help explain why a different sort of drug, Vytorin, which keeps the body from absorbing cholesterol, showed no plaque-prevention effect in a recent study, even though it did reduce LDL levels in the blood. It may also help explain why some studies, though none is definitive, suggest that statins may help slow the progress of Alzheimers — another illness where inflammation may play a part.

The biggest question about statins is whether they should only be given to people who have already had heart attacks — there's clear evidence that the drugs save lives in that case. Or should they also go to anyone with elevated cholesterol? There, the evidence is quite unclear, which is why many doctors insist on seeing at least one more heart risk factor (obesity, age over 50, high blood pressure, a family history of heart disease) before prescribing.

—Michael D. Lemonick