Page 165 - Clinical Pearls in Cardiology

Chapt er
9 Ischemic Heart Disease

1. What is meant by unstable angina?
Stable angina is the result of myocardial ischemia due
to the fixed atheromatous stenosis of one or more
coronary arteries (causes mainly demand led myocardial
ischemia). Unstable angina is the result of myocardial
ischemia caused by the dynamic obstruction of a
coronary artery due to plaque rupture with superimposed
thrombosis and spasm (causes mainly supply-led
myocardial ischemia). Unstable angina is defined as
angina pectoris with at least one of the three features:
1. Occurs at rest or with minimal exertion and lasts for
more than 10 minutes.
2. Occurs with a crescendo pattern (more severe, more
frequent, more prolonged).
3. Is severe and of new onset (within the prior 4 to
6 weeks).
2. What are acute coronary syndromes?
The term “acute coronary syndrome” refers to any
constellation of clinical symptoms that are compatible
with acute myocardial ischemia. Acute coronary
syndromes encompass acute myocardial infarction
and unstable angina. The resting ECG is essential in the
evaluation of a patient presenting with clinical features
of an acute coronary syndrome. Patients with ischemic