Introduction
As an active muscle, the heart needs a continuous supply of oxygen. The
coronary arteries have the job of carrying oxygen to the heart. These arteries
have a difficult job to do because they undergo intense compression every time the
heart beats. This job becomes even more difficult when the arteries are damaged by
atherosclerosis (commonly, though not quite accurately,
called hardening of the arteries) in a condition called coronary artery
disease.
In coronary artery disease, the passages inside the coronary arteries become
narrowed by plaque deposits, which decreases blood flow. When the blood flow is
decreased to a sufficient extent, pain caused by oxygen deprivation occurs. This
pain is known as angina pectoris. Angina tends to wax and wane, generally
worsening with exercise.
A heart
attack may occur after years of angina or with no warning.
Most heart attacks occur when a blood clot (thrombus) forms on the roughened wall
of an atherosclerotic coronary artery. Such a blood clot may lead to a sudden and
complete blockage of the artery. More rarely, a spasm of a coronary artery may cut
off blood flow. In either case, the cells of the heart fed by that artery begin to
die. The region of dead cells is called an infarct,
leading to the technical name for a heart attack: myocardial infarction (MI).
The classic symptom of a heart attack is intense, central chest pressure. Other common symptoms include pain or heaviness in the left arm, nausea, shortness of breath, increased perspiration, and a feeling of impending doom. Many people who have had an MI describe chest discomfort or pain in the jaw, teeth, arm, or abdomen. Women are more likely than men to feel pain in their backs. Often, symptoms appear gradually and are intermittent or vague. One-quarter of persons, more often women and people with diabetes, experience no symptoms.
When a heart attack occurs, emergency treatment at a hospital can minimize the
extent of permanent damage to the heart. “Clot busting” drugs, if given soon
enough, can open the coronary arteries, allowing blood to flow again. Other
methods of restoring blood flow include procedures known as angioplasty,
stenting, and bypass surgery. The aim is to save
those heart cells that are in danger of dying. Recovery after a heart attack
depends on the extent of heart damage. If only a small portion of the heart has
died, or if it is in a relatively less important region, symptoms may be slight.
More severe damage can cause the heart to pump improperly, leading to congestive
heart failure.
During the first several days following a heart attack, the heart has a
tendency to lose its normal rhythm and fall into a dysfunctional pattern of
beating that does not properly circulate blood. Treatment aimed to prevent or
treat this condition, called an arrhythmia, is conducted in a cardiac
intensive care unit.
Long-term treatment to reduce the risk of heart attacks generally involves aspirin to prevent blood clots and treatments to slow, stop, or reverse atherosclerosis. The latter is accomplished through the use of medications that keep cholesterol and blood pressure within normal limits and by increasing exercise and improving other aspects of one’s lifestyle.
Principal Proposed Natural Treatments
The most important contribution of natural medicine in the realm of heart attacks is prevention, not treatment. Atherosclerosis, which causes most heart attacks, is accelerated by high blood pressure and high cholesterol, and possibly by high levels of homocysteine in the blood. Natural treatments used for these conditions are worth considering. However, natural therapies for high blood pressure and high cholesterol are generally less effective than the conventional approaches. Persons interested in using natural treatments should first consult with a physician to determine how long it is safe to experiment. If natural therapies have not controlled the heart condition within the prescribed time, it may better to use conventional therapies.
Other Proposed Natural Treatments
Several natural treatments have shown promise for use with conventional treatment in the period following a heart attack. Note, however, that people who have recently had a heart attack should not use any herbs or supplements except under the supervision of a physician. Furthermore, none of these treatments can substitute for standard care; at most, they might be helpful if used in addition to it.
Coenzyme Q?
10. The supplement coenzyme Q10
(CoQ10) is thought to improve heart function. In a double-blind
trial, 145 people who had recently experienced a heart attack were given either
placebo or 120 milligrams (mg) of CoQ10 daily for twenty-eight days.
The results showed that participants receiving CoQ10 experienced
significantly fewer heart-related problems, such as episodes of angina pectoris or
arrhythmia, or recurrent heart attacks. CoQ10 taken with the mineral
selenium has also shown promise for people who have survived a heart attack.
L-carnitine. The amino acid L-carnitine has shown potential value during the first few weeks after an MI. A double-blind, placebo-controlled study that followed 101 people for one month after a heart attack found that the use of L-carnitine, in addition to standard care, reduced the size of the infarct (area of dead heart tissue). Other complications of heart attack were reduced too. Similar benefits also were seen in a one-year, controlled study of 160 people who had just experienced a heart attack; however, because this study was not double-blind, its results are not reliable.
In the months following a severe heart attack, the heart often enlarges and loses function. L-carnitine has shown some potential for helping the first of these complications, but not the second. In a twelve-month, double-blind, placebo-controlled study of 472 people who had just experienced a heart attack, the use of carnitine at a dose of 6 grams per day significantly decreased the rate of heart enlargement. However, heart function was not improved. A three-month, double-blind, placebo-controlled study of sixty people who had just had a heart attack also failed to find improvements in heart function with L-carnitine. (Heart enlargement was not studied.)
Results consistent with those of the foregoing studies were seen in a
six-month, double-blind, placebo-controlled study of 2,330 people who had just had
a heart attack. Carnitine failed to produce significant reductions in
mortality or heart failure (serious decline in heart function) over the six-month
period. However, it did find reductions in early death. (For statistical reasons,
the meaningfulness of this last finding is questionable: It was a secondary
endpoint rather than a primary one.)
Fish oil. Fish oil contains healthy fats in the
omega-3 fatty acid category. Incomplete evidence suggests that fish oil
supplements may help prevent heart attacks and prevent sudden death after a heart
attack. This benefit may come from a number of fish oil’s actions, including
preventing dangerous heart arrhythmias and reducing heart rate.
Garlic. In one study, 432 people who had had a heart attack were
given either garlic oil extract or no treatment for three years. The results
showed a significant reduction of second heart attacks and about a 50 percent
reduction in death rate among those taking garlic. People who take aspirin to
prevent heart attacks should not take garlic supplements, as the combination
could lead to excessive bleeding.
Red yeast rice. Because of its purported ability to lower
cholesterol, red
yeast rice (made by fermenting a type of yeast called
Monascus purpureus over rice) has been studied in persons with
heart
disease. A double-blind study in China compared an alcohol
extract of red yeast rice (Xuezhikang) with placebo in almost five thousand people
with heart disease. In the four-year study period, the use of the supplement
reportedly reduced the heart attack rate by about 45 percent compared with
placebo, and total mortality was reduced by about 35 percent. At least three other
studies, all from this same original population of participants, have found
similar results in diabetics with heart disease and in persons with a previous
heart attack, with surprisingly large reductions in the rates of coronary events
(such as heart attack) and mortality. These levels of reported benefit, however,
are so high and so similar as to raise questions about their reliability.
Antioxidants. Antioxidant supplements help neutralize
free
radicals, which are dangerous, naturally occurring chemicals
that may accelerate heart cell death following a heart attack (among their many
other harmful effects). In a double-blind trial, people who had just experienced a
heart attack were given either placebo or a mixture of antioxidants (vitamin A,
vitamin C, vitamin E, and beta-carotene) for twenty-eight days. The results
indicated that the use of antioxidants minimized the extent of heart cell
damage.
Magnesium. The mineral magnesium is sometimes suggested for
stabilizing the heart after a heart attack, but one study actually found a
negative effect. In this one-year, double-blind, placebo-controlled trial of 468
people who had just experienced a heart attack, the use of a magnesium supplement
at a dose of 360 mg daily failed to prevent heart-related events (defined as heart
attack, sudden cardiac death, or need for cardiac bypass) and actually may have
increased the risk slightly.
Arginine. The supplement arginine has
been proposed for aiding recovery from a heart attack. In one double-blind study,
arginine did not cause harm, and it showed potential modest benefit. However, in
another study, arginine failed to prove helpful and possibly increased the death
rate of those who had a heart attack.
Other herbs and supplements. Other herbs and supplements that are sometimes said to be useful after a heart attack, but that lack reliable substantiation, include glycine, hawthorn, inosine, and lipoic acid.
Lifestyle modifications. Evidence suggests that intensive lifestyle modification, involving an extremely low-fat diet, exercise, and stress reduction, can actually reverse coronary artery disease in people who have had, or are at high risk for, heart attacks. It is not clear whether less ascetic approaches can achieve similar effects. However, there is evidence that less intensive low-fat and Mediterranean-style (low-fat plus high fish oil) diets can decrease the risk of recurrent heart attacks and similar cardiac events in persons who already have experienced a heart attack.
Chelation therapy. Some alternative medicine physicians recommend
the use of intravenous infusions of a chemical called ethylenediaminetetraacetic
acid to clear out the arteries of the heart, a method called chelation
therapy. This method is based on an outmoded understanding of
atherosclerosis, and it is most likely ineffective.
Herbs and Supplements to Use with Caution
Numerous herbs and supplements may interact adversely with drugs used to prevent or treat heart attacks.
Bibliography
Calo, L., et al. “N-3 Fatty Acids for the Prevention of Atrial Fibrillation After Coronary Artery Bypass Surgery.” Journal of the American College of Cardiology 45 (2005): 1723-1728.
Lu, Z., et al. “Effect of Xuezhikang, an Extract from Red Yeast Chinese Rice, on Coronary Events in a Chinese Population with Previous Myocardial Infarction.” American Journal of Cardiology 101 (2008): 1689-1693.
Mozaffarian, D. “Fish and N-3 Fatty Acids for the Prevention of Fatal Coronary Heart Disease and Sudden Cardiac Death.” American Journal of Clinical Nutrition 87 (2008): 1991S-1996S.
Raitt, M. H., et al. “Fish Oil Supplementation and Risk of Ventricular Tachycardia and Ventricular Fibrillation in Patients with Implantable Defibrillators.” Journal of the American Medical Association 293 (2005): 2884-2891.
Schulman, S. P., et al. “L-arginine Therapy in Acute Myocardial Infarction: The Vascular Interaction with Age in Myocardial Infarction (VINTAGE MI) Randomized Clinical Trial.” Journal of the American Medical Association 295 (2006): 58-64.
Tarantini, G., et al. “Metabolic Treatment with L-carnitine in Acute Anterior ST Segment Elevation Myocardial Infarction.” Cardiology 106 (2006): 215-223.
Tuttle, K. R., et al. “Comparison of Low-Fat Versus Mediterranean-Style Dietary Intervention After First Myocardial Infarction (from the Heart Institute of Spokane Diet Intervention and Evaluation Trial).” American Journal of Cardiology 101 (2008): 1523-1530.
Yokoyama, M., et al. “Effects of Eicosapentaenoic Acid on Major Coronary Events in Hypercholesterolaemic Patients (JELIS).” The Lancet 369 (2007): 1090-1098.
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