What happens during angina pectoris physiologically?

What happens during angina pectoris physiologically? this is what I have so far "Angina pectoris is a result of myocardial ischemia. Myocardial ischemia happens when blood flow to the heart is decreased and there becomes an imbalance between myocardial blood supply and oxygen demand. Angina pectoris becomes present when the cardiac workload and oxygen demand overcome the ability of coronary arteries to supply an appropriate amount of oxygenated blood." but I need to go deeper into the physiology of it.