Stable angina and unstable angina lie on stable vs. unstable. Unstable angina is a more critical condition that requires hospitalization for emergency treatment. Stable angina is relatively stable and less dangerous. The difference is as follows: 1, stable angina is coronary heart disease patients have been diagnosed with angina, but after treatment, the frequency, length of time interval, the degree of relatively stable, and even some patients have fewer episodes; 2, unstable angina generally refers to the atherosclerotic plaque and disintegration of the destruction, and then the release of more inflammatory substances, which will cause vascular spasm or contraction, or plaque growth, resulting in further blood vessel narrowing, which is an unstable state. So unstable angina includes exertion worsening angina, used to walk a mile is fine, now walk a few hundred meters began to feel uncomfortable, angina attack is more frequent, do not know when a sudden attack, the trigger is heavy physical labor or moderate physical labor, and now a little bit of activity onset of attack, which belongs to the category of unstable angina. There are also some special unstable angina, such as lying angina, such as lying down on the attack, indicating that the heart ischemia has been more serious, lying down at night after the increase in the amount of blood back to the heart, angina attack. There is also variant angina where coronary spasm is also more severe, often suggesting more endothelial damage to the blood vessels, all of which fall into the category of unstable.