The history of EECP begins in the early 1950s, when researchers discovered that the heart was doing two different kinds of work. The first type of work occurred during the pumping part of the heartbeat (systole) during which the heart needed to overcome the blood pressure in the aorta in order to pump blood through it. The second type of work occurred during the relaxed part of the heartbeat (diastole) during which the heart received blood via backflow from the aorta. This was described as the difference between pressure work and flow work.

Counterpulsation was introduced as a strategy by which the blood flow from the aorta back to the heart could be increased during diastole. The increased blood flow to the heart through the coronary arteries would provide the heart with more oxygen, thereby improving circulation and strengthening the cardiopulmonary system.

In 1958, Harvard researchers documented positive results from counterpulsation in laboratory studies, and animal studies in the early 1960s supported these results. From this research, American researchers began to develop a device that could be surgically implanted in the chest to produce counterpulsation (an intra-aortic balloon pump [IABP]). This device is used during open-heart surgery to help wean patients off the heart-lung machine.

While most American physicians were pursuing invasive techniques such as the IABP, Chinese physicians were developing one of the other findings that came from Harvard in the 1960s. The Harvard researchers had discovered that counterpulsation could be achieved without inserting a device into the aorta. Instead, cuffs were applied to the lower legs and timed to fill and empty of water in the same rhythm as the patient’s heartbeat. By gently compressing the blood vessels in the legs, this increased the blood flow to the heart during the diastole phase of the heartbeat.

Chinese physicians pursued this painless, noninvasive technique for achieving counterpulsation and have been developing and refining it over the last 40 years. Today the technique of enhanced external counterpulsation uses a pressure suit that sends counterpulsation waves through computer–controlled pneumatic cuffs located at three points on the leg. This modern version of the technique was introduced in 1983 and continues to be used today.

Precisely timed by computer, these modern cuffs inflate and deflate rapidly between heart beats. The modern cuffs used today fill with air instead of water, for the greater comfort of the patient and the greater ease of the physician. The three cuffs also fill sequentially, one at a time, rather than suddenly filling all at once.

In 1989, researchers from the State University of New York at Stony Brook determined that enhanced external counterpulsation continued to show helpful effects on patients even three years after treatment. There are no reported risks of complication, and as of this time, centers are opening up across the country to provide this service. However, in 2002, the American Heart Association and the American College of Cardiology issued guidelines on treating angina stating that more studies are required on EECP before it can be recommended as a standard treatment for angina. So far, EECP has not been widely accepted in clinical practice.

In 2004, several studies also found that EECP shows some benefit for patients with stabilized heart failure. These study results were confirmed in 2006, with publication of the PEECH (Prospective Evaluation of Enhanced External Counterpulsation in Congestive Heart Failure) study. This study found that patients with mid- to moderate-severe heart failure experienced an improvement in their New York Heart Association (NYHA) class after counterpulsation. However, the long-term safety and effects of EECP are unknown among these patients and more long-term studies are needed.