Table of Contents
What is Angina Pectoris and Definition
Angina Pectoris – chest discomfort originating from the HEART, usually resulting from restricted BLOOD flow due to CORONARY ARTERY DISEASE (CAD) that occludes (blocks) one or more of the CORONARY ARTERIES. Coronary ARTERY spasm, especially that resulting from COCAINE use, may also cause angina. Some people experience a crushing pressure that radiates into the left shoulder, arm, and throat. Other people experience discomfort similar to DYSPEPSIA (indigestion or heartburn). Though the nature and quality of discomfort varies among individuals, for most people angina pectoris is a chronic (long-standing) condition with predictable symptoms that appear with exertion and subside with rest.
Angina pectoris does not signal HEART ATTACK, though it is a warning that atherosclerotic accumulations in the coronary arteries have narrowed the arterial lumen (channel or opening through which blood flows) by 70 percent or more. When exercise or other stress (such as stepping out into a cold wind) increases the demand on the heart to pump more blood, the stiffened and narrowed coronary arteries, which in health could expand to nearly double the volume of blood flowing through them, cannot respond. The heart MUSCLE(MYOCARDIUM) fails to receive the oxygen it needs as well as to dispose of the metabolic wastes that are accumulating within its cells.
Treatment and Symptoms of Angina Pectoris
Treatment for angina pectoris generally combines relieving symptoms and mitigating the underlying cause. Medications to treat angina pectoris cause smooth muscle tissue (such as makes up the walls of the arteries) to relax. This allows the coronary arteries to modestly increase the flow of blood, which usually is sufficient to ease symptoms. Commonly prescribed medications include nitrates such as nitroglycerin and isosorbide, beta antagonist (blocker) medications such as atenolol and propanolol, and calcium channel antagonist (blocker) medications such as diltiazem and verapamil. Cardiologists typically recommend ASPIRIN THERAPY for people who have angina pectoris, to help prevent MYOCARDIAL INFARCTION (blood clot that blocks the flow of blood, causing heart tissue to die).
For some people, the most effective treatment is ANGIOPLASTY to repair, or CORONARY ARTERY BYPASS GRAFT (CABG) to replace, occluded coronary arteries. However, many people who have angina pectoris remain stable with medication therapy. Cardiologists disagree about the value of CABG for people whose only symptom of disease is angina pectoris, because there is growing evidence that the risks of the surgery (including rapid occlusion of the grafts) do not counterbalance the benefits.
Unstable Angina and Variant Angina
Two forms of angina are more serious: unstable angina and variant angina. In unstable angina, also called acute coronary insufficiency or preinfarction angina, symptoms are unpredictable and do not necessarily correlate to increased demands on the heart such as physical activity may place. Many cardiologists consider unstable angina a precursor to heart attack. With unstable angina, symptoms may occur during sleep or at rest, are often intense and extended, and progressively more severe. Sublingual (under the tongue) nitroglycerin may provide relief. As the underlying heart disease progresses, however, symptoms become more difficult to control. Angioplasty or CABG is often the most viable treatment options.
In variant angina, also called Prinzmetal’s angina, spasm of a coronary artery causes symptoms that tend to occur without provocation at certain times of the day. Specific changes in the ELECTROCARDIOGRAM (ECG) accompany the symptoms. Medication (nitroglycerin or calcium channel blocker) is the most effective treatment for most people who have variant angina. CABG may relieve symptoms that do not respond to medication, though typically occlusion affects only one coronary artery to cause the symptoms.
Generally the risks of OPEN HEART SURGERY, such that CABG requires, outweigh the potential benefits to replace a single coronary artery. TRANSMYOCARDIAL LASER REVASCULARIZATION (TMLR), a surgical procedure less invasive than CABG that cardiologists began using in 1998, shows promise for relieving angina that does not respond to other treatment. In TMLR, the surgeon uses a laser to pierce the left ventricle with narrow channels. As the channels heal they cause new blood vessels to develop in the myocardium, improving the flow of blood to the heart muscle.