Radiographic Appearance
In coronary angiography there is constriction of one or more
of the coronary arteries and their branches, occasionaly
arthrosclerotic plaque calcifications can be see in the cardiac
shadow on a plain chest radiograph.A more complex stress test
involves picturing the blood flow pattern in the heart muscle during
peak exercise and after rest. A tiny amount of a radioisotope,
usually thallium, is injected into a vein at peak exercise and is
taken up by normal heart muscle. A radioactivity detector and
computer record the pattern of radioactivity distribution to various
parts of the heart muscle. Regional differences in radioisotope
concentration and in the rates at which the radioisotopes disappear
are measures of unequal blood flow due to coronary artery narrowing,
or due to failure of uptake in scarred heart muscle.
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Pathology
ANGINA PECTORIS ("ANGINA") IS A recurring pain or discomfort in the
chest that happens when some part of the heart does not receive
enough blood. It is a common symptom of coronary heart disease (CHD),
which occurs when vessels that carry blood to the heart become
narrowed and blocked due to atherosclerosis
Angina feels like a pressing or squeezing pain, usually in the
chest under the breast bone, but sometimes in the shoulders, arms,
neck, jaws, or back. Angina is usually precipitated by exertion.
Angina pectoris often recurs in a regular or characteristic
pattern. Commonly a person recognizes that he or she is having
angina only after several episodes have occurred, and a pattern has
evolved. The level of activity or stress that provokes the angina is
somewhat predictable, and the pattern changes only slowly. This is
"stable" angina, the most common variety.
Instead of appearing gradually, angina may first appear as a very
severe episode or as frequently recurring bouts of angina. Or, an
established stable pattern of angina may change sharply; it may by
provoked by far less exercise than in the past, or it may appear at
rest. Angina in these forms is referred to as "unstable angina" and
needs prompt medical attention.
The term "unstable angina" is also used when symptoms suggest a
heart attack but hospital tests do not support that diagnosis. For
example, a patient may have typical but prolonged chest pain and
poor response to rest and medication, but there is no evidence of
heart muscle damage either on the electrocardiogram or in blood
enzyme tests
There are two other forms of angina pectoris. One, long recognized
but quite rare, is called Prinzmetal's or variant angina. This type
is caused by vasospasm, a spasm that narrows the coronary artery and
lessens the flow of blood to the heart. The other is a recently
discovered type of angina called microvascular angina. Patients with
this condition experience chest pain but have no apparent coronary
artery blockages. Doctors have found that the pain results from poor
function of tiny blood vessels nourishing the heart as well as the
arms and legs. Microvascular angina can be treated with some of the
same medications used for angina pectoris.
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