What are the causes of Angina Pectoris?

Angina can be caused by abnormal coronaries or normal coronaries
Angina due to abnormal coronaries
Coronary disease - Atherosclerotic and non - atherosclerotic-Vasculitis, vasospasm, embolism. Congenital anomaly
Angina with normal coronaries

• Aortic stenosis, HOCM, MVP
• Hyperviscosity - polycythemia
• Right ventricular angina seen in pulmonary artery hypertension PAH
• Systemic hypertension and LVH
• Severe anemia.

Aortic stenosis: It results in  decreased stroke volume, reducing coronary perfusion and compression of coronaries by hypertrophied myocardium, so decreased oxygen supply and increased oxygen demand by the hypertrophied myocardium. The ischaemic burden is increased by reduced capillary density  and coexistent atherosclerosis.
Aortic regurgitation:Aortic regurgitation results in decreased coronary perfusion as a result of rim off of blood back into the leftventricle  and periphery during diastole; in syphilitic AR, there is coronary ostial stenosis also.
Hypertrophic obstructive cardiomyopathy: mechanism of angina is same as in aortic stenosis.
Systemic hypertension:Systemic hypertension result in  decreased diastolic coronary perfusion as a result of left ventricular hypertrophy.
Severe anaemia
Connective tissue disorders (due to arteritis) 
Extreme tachyarrhythmias.