Kantrowitzs first described the principle “phase shift diastolic augmentation” in 1953. Physicians and physicists at Harvard and elsewhere related this principle to oxygen consumption and cardiac workload. This understanding led to the concept of mechanically induced “cardiac assistance” for patients with low cardiac output syndromes, especially cardiogenic shock.
Beginning in the 1960’s, research on mechanically induced “Cardiac assistance” followed two distinct paths; one involved the use of a balloon positioned inside the descending thoracic aorta that would inflate during diastole and deflate at the onset of systole, and another of the vascular beds in the lower limbs. The first came to be known as the intra-aortic balloon pump (IABP). The second evolves as to what is now referred as ECP. These early systems were somewhat primitive by today’s standards. But both forms of counterpulsation clearly demonstrated the potential for increasing survival of patients with myocardial infarction and cardiogenic shock as well as for relief of angina pectoris.
In 1960’s Three groups (Birtwell and Soroff, Dennis and Osborn) independently developed hydraulically activated external counter pulsation devices and found the technique effective in improving survival after myocardial infarction complicated by cardiogenic shock. Initial experience with a crude external counterpulsation device used in stable angina saw relief of angina symptoms with angiographic evidence of increased vascularity.
Early hydraulic systems for ECP eventually gave way to pneumatics. This along with refinements of the compression element of the system, helped to improve outcomes and patient comfort. The national institutes of health (NIH) in the USA played a significant role in the evolution of the modern ECP systems by advocating the additional of a second cuff and the use of a sequential cuff inflation to increase the amount of blood being returned to the heart and as a results diastolic augmentation.
Before 1970’s all ECP’s were “non-sequenced” pulsation. During the 1970’s, Zheng and Associates at Sun yat Sen University in China reported on a newly designed 3-stage pneumatic pulsation system. In this trial the effect of sequenced cuff inflation were studied in patients with angina, the system provided long-term symptomatic relief with minimal relapse, following 36 hours of treatment.
Their clinical experience led to the installation of more than 1,500 external counterpulsation units in China during the past 15 years leading to the development and refinement of the EECP technique and device.
