UNSTABLE ANGINA

IntroductionAngina pectoris, commonly known as angina, is

severe chest pain[1] due to ischemia (a lack of blood, hence a lack of oxygen supply) of the heart muscle, generally due to obstruction or spasm of the coronary arteries (the heart's blood vessels). Coronary artery disease, the main cause of angina, is due to atherosclerosis of the cardiac arteries. The term derives from the Latin angina ("infection of the throat") from the Greek ἀγχόνη ankhone ("strangling"), and the Latin pectus ("chest"), and can therefore be translated as "a strangling feeling in the chest".

There is a weak relationship between severity of pain and degree of oxygen deprivation in the heart muscle (i.e., there can be severe pain with little or no risk of a heart attack, and a heart attack can occur without pain).

Worsening ("crescendo") angina attacks, sudden-onset angina at rest, and angina lasting more than 15 minutes are symptoms of unstable angina (usually grouped with similar conditions as the acute coronary syndrome). As these may herald myocardial infarction (a heart attack), they require urgent medical attention and are generally treated as a presumed heart attack.

Classification of angina pectoris

Stable anginaAlso known as effort angina, this refers to the more

common understanding of angina related to myocardial ischemia. Typical presentations of stable angina is that of chest discomfort and associated symptoms precipitated by some activity (running, walking, etc.) with minimal or non-existent symptoms at rest. Symptoms typically abate several minutes following cessation of precipitating activities and resume when activity resumes. In this way, stable angina may be thought of as being similar to claudication symptoms.

Unstable angina Unstable angina (UA) (also "crescendo angina;" this

is a form of acute coronary syndrome) is defined as angina pectoris that changes or worsens.

It has at least one of these three features:it occurs at rest (or with minimal exertion), usually

lasting >10 min;it is severe and of new onset (i.e., within the prior 4–

6 weeks); and/orit occurs with a crescendo pattern (i.e., distinctly

more severe, prolonged, or frequent than previously).

What is Unstable Angina?Angina (chest pain or

chest discomfort produced when the heart muscle is not getting enough blood flow) is considered "unstable" when it no longer follows the predictable patterns typical of "stable angina."

Cont..Unstable angina is one of the types of "

Acute Coronary Syndrome (ACS)," a series of conditions most commonly produced by the rupture of a plaque in a coronary artery. All types of ACS, including unstable angina, should be considered medical emergencies.

Unstable angina is "unstable" not only because a plaque has ruptured (a situation which always threatens to progress to a myocardial infarction), but also because the symptoms it produces - the angina - generally occurs much more frequently, often at rest, lasts much longer, and begins responding poorly to nitroglycerin.

Unstable Angina

Cont..Unstable angina is called "unstable" for two reasons.First, in contrast to stable angina, symptoms occur in a

more random and unpredictable fashion. While in stable angina, symptoms typically are brought on by exertion, fatigue, anger, or some other form of stress, in unstable angina symptoms can (and often do) occur without any apparent trigger. In fact, unstable angina often occurs at rest, and can even wake people from a restful sleep. Furthermore, in unstable angina, the symptoms often persist for more than just a few minutes, and nitroglycerinoften fails to relieve the pain. So: unstable angina is "unstable" because symptoms may occur more frequently than usual, without any discernable trigger, and may persist for a long time.

Cont..Second, and more importantly, unstable angina is

"unstable" because, as with all forms of ACS, it is most often caused by the actual rupture of aplaque in a coronary artery. In unstable angina, the ruptured plaque, and the blood clot that is almost always associated with the rupture, are producing partial blockage of the artery. The partial blockage may take a "stuttering" pattern (as the blood clot grows and shrinks), producing angina that comes and goes in an unpredictable fashion. If the clot should cause complete obstruction of the artery (which happens commonly), the heart muscle supplied by that affected artery is in grave danger of sustaining irreversible damage. In other words, the imminent risk of a complete myocardial infarction is very high in unstable angina. Obviously, such a condition is quite "unstable," and for this reason is a medical emergency.

Sign and symptoms When heart is not

getting enough oxygen, a type of acute chest pain called unstable angina may occur. In medical terminology, acute pain means the pain comes on very suddenly and may be severe. Acute chest pain may appear, change and worsen very quickly. Unstable angina can be a warning sign that a heart attack may happen soon.

Cont.. Chest Pain - A main symptom of unstable angina is the

sudden onset of chest pain. This pain may be felt in other areas of the upper body including the arm, shoulder, back, neck or jaw. Resting will usually not take reduce the symptoms of an unstable angina.

Feeling- Pain from unstable angina may feel crushing,

burning, tight, squeezing, choking or aching. It has also been described as simply discomfort or heaviness. The pain associated with the condition will not easily go away with medicine once the onset has begun.

Cont..Nausea & Sweating- Often times, unstable angina may also bring with it a

certain amount of nausea or even the feeling of indigestion. This nausea may be accompanied by sweating, though the two symptoms are not exclusive to one another.

Shortness of Breath- You may also begin to experience a shortness of breath

with unstable angina, even when you're at rest. Fatigue- If you're suffering from unstable angina, you may

begin to notice an almost overwhelming feeling of fatigue and exhaustion.

Cont.. Dizziness & Lightheadedness- It isn't uncommon to for someone with

unstable angina to experience a sense of dizziness or lightheadedness with the chest pain.

Cont..Other Symptoms- Other symptoms may include upper stomach

pain that could be mistaken for heartburn. The elderly, diabetics and women are more likely to have symptoms such as dizziness, shortness of breath and weakness. You may have trouble breathing, feel very tired or have nausea or vomiting.

Risk factorsCoronary artery disease is the most common cause of

unstable angina.Risk factors include:- Diabetes Aging High blood pressure High low- density lipoprotein(LDL) cholesterol Low high- density lipoprotein(HDL) cholesterol Lack of exercises Obesity & smoking Males and those individuals with a family history of

coronary heart disease before the age of 50 are also at higher risk for developing the condition.

Daignosis ECGblood tests forcardiac enzyme testing.

Cont..The classic symptoms of angina include chest pressure

or pain, sometimes squeezing or “heavy” in character, often radiating to the jaw or left arm. Unfortunately, many patients with angina do not have classic symptoms. Their discomfort may be very mild, and may be localized to the back, abdomen, shoulders, or either or both arms. Nausea, breathlessness, or merely a feeling of heartburn may be the only symptom. What this means, essentially, is that anyone middle aged or older, especially anyone with one or more risk factors for coronary artery disease, should be alert to symptoms that might represent angina.

Diagnosis How Is Unstable Angina Diagnosed?Symptoms are critically important in making the

diagnosis of unstable angina, or indeed, any form of ACS. In particular, if you have one or more of the following three symptoms:-

Angina at rest, especially if it lasts more than 20 minutes at a time

New onset angina that markedly limits the patient's ability to engage in physical activity

An increase in prior stable angina, with episodes that are more frequent, longer lasting, or occur with less exertion than previously

Cont..If the portion of the ECG known as "ST segments"

are elevated (which indicates that the artery is completely blocked), and the cardiac enzymes are increased (which indicates cardiac cell damage), a "large" myocardial infarction (MI) is diagnosed (also called an "ST-segment elevation MI," or STEMI)

If the ST segments are not elevated (so the artery is not completely blocked), but the cardiac enzymes are increased (cell damage is present), a "small" MI is diagnosed (also called a "non-ST segment MI," or NSTEMI)

Cont..If the ST segments are not elevated and the enzymes are

normal (meaning the artery is not completely blocked and no cell damage is present), unstable angina is diagnosed.

Notably, unstable angina and NSTEMI are similar conditions. In each condition, a plaque rupture has occurred in a coronary artery, but the artery is not completely blocked so at least some blood flow remains. In both of these conditions, the symptoms of unstable angina are present. The only difference is that in an NSTEMI enough heart cell damage has occurred to produce an increase in cardiac enzymes. Because these two conditions are so similar, their treatment is identical.

Cont..What Is the Treatment For Unstable

Angina (and NSTEMI)If you have either unstable angina or

NSTEMI, you will be treated with one of two general approaches: a) treat aggressively with drugs to stabilize the condition, then evaluate non-invasively, or b) treat aggressively with drugs to stabilize the condition, and schedule early invasive intervention (generally, angioplasty and stenting).