Angina strictly is a symptom not a disease. Angina is caused when the heart runs out of oxygen - like a stitch or cramp.

Angina can therefore occur either when there is not enough blood supply to the heart (as with coronary artery disease when narrowings prevent the blood getting through) or when the energy that the heart requires to beat effectively is so great that not even normal coronary arteries can deliver enough – as in aortic valve disease.

The cause of angina can sometimes be a combination of two or more pathologies.