Understanding Angina: Unstable Angina

This is part seven of our series the Heart of the Matter. Part six can be found here. We know you want to read the disclaimer.

What is important to note is a change in angina pattern as angina can become unstable. Instability of symptoms also reflects instability of the plaque and may possibly indicate plaque progression. If the angina now becomes more frequent, is brought on by lesser activity, lasts longer then before, is more severe, or comes on even at rest, these are signs of instability (unstable angina) which may herald the possibility of an impending heart attack. Should this occur, it is very important to consult a doctor as soon as possible. It is better to be over cautious, then to ignore, and be careless.

The diagnosis of angina pectoris is very much dependent on the history provided by the patient. Tests can be carried out to see the context of the patient. A history of probable angina, in a patient at risk of CAD must alert a doctor to the diagnosis of angina pectoris, from CAD. What is also important from the history is that the doctor can assess the severity of the angina, and from that, the severity of the CAD by using the various clinical grading scores available, eg., the American heart association grading or the popular Canadian cardiovascular society grading is as follows:

Canadian cardiovascular society classification for Angina

Class I - Ordinary physical activity does not cause angina, such as walking, climbing stairs. Angina with strenuous, rapid, or prolonged exertion at work or recreation.

Class II - Slight limitation of ordinary activity. Angina occurs on walking or climbing stairs rapidly, walking uphill, walking or stair climbing after meals, or in cold, or in wind, or under emotional stress, or only during the few hours after awakening. Walking more than two blocks on the level and climbing more than one flight of ordinary stairs at a normal pace and in normal condition.

Class III - Marked limitations of ordinary physical activity. Angina occurs on walking one to two blocks on the level and climbing one flight of stairs in normal conditions and at a normal pace.

Class IV - Inability to carry on any physical activity without discomfort -- angina symptoms may be present at rest.

In the next part we will discuss vasospastic angina.