To meet the needs of a VAD user, the design must be based on a perfect medical understanding of the mechanism of the heart, heart failure, its causes, symptoms, progressive stages and so on. An artificial device would need to address the health problems and avoid undesirable results.

It is the engineers' job to make a device out of the design - not easy, because it takes time, energy and experience to realize the functions the design requires, and minimize mechanism-related incidences, and decide what material and technology to use.

A computer-aided testing system is also needed to virtually test the design to modify it, and the effectiveness of such a test is dependent on the reliability of the hardware and software system involved.

"The design is like a draft blueprint drawn by the medical team, and only the closest cooperation and communication between the medical team and the engineers can make the design come true," says Zhang Jiemin, director of the animal trial center at the hospital.

"Any negligence on either team will lead to failure."

The VAD the hospital has designed is a new type that few countries have. It will be smaller, with greater stability and efficiency, but less likely to cause infection, thrombosis, or limit the users' daily activities.

By this reckoning, it is more demanding on both the medical and engineering teams.

Tianjiu, the sheep, was the 18th animal to be tried on the program. All former trials had failed.

With the VAD implanted, the ram is healthy and cheerful, and apparently enjoying his high profile. He poses for the cameras when there are visitors taking pictures.

He also has the company of another sheep, whose grandmother and mother were also trial subjects.

Tianjiu literally means "forever", and the hospital hopes the sheep will live a healthy life to a ripe old age.

The hospital plans to carry out clinical trials in a year, and hopefully there will be good results, according to Liu Xiaocheng, the hospital president.

His optimism is not shared by all, and Yuan Biao, a cardiac surgeon with No 1 Hospital of Tsinghua University says he believes locally made VADs will not be as good as those now widely used in foreign countries, at least not in the near future.

He feels there is too much of a gap in technology. But he applauds the current efforts, saying it is necessary for China to develop its own VADs.