External counterpulsation (ECP) is a procedure performed on individuals with ischemic cardiomyopathy in order to diminish the symptoms of their ischemia. In various studies, ECP has been shown to relieve angina1,2, improve exercise tolerance³, and decrease the degree of ischemia in a cardiac stress test2,3.ECP is a technique while EECP. IECP. SECP are all brand names of companies manufacturing them.

From http://en.wikipedia.org/wiki/Enhanced_external_counterpulsation