Angina often falls into one of two
categories: stable or unstable.
Stable angina 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. It is the most common variety of angina.
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.
Are there other types of
There are two other forms of angina.
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
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 'regular' angina