Up-beat development of an artificial heart Surgeons at the Alfred Hospital in Melbourne and at the Royal North Shore Hospital in Sydney have completed initial animal trials of a new type of artificial heart developed by engineers in the Health Technologies KURS group. The device was developed in conjunction with Australian medical device manufacturer Micromedical Industries Limited (MMI).

These trials were the first full test of the device, which is designed to take over the pumping function of the human heart's left ventricle when it is severely weakened by disease. The basic control software for the artificial heart was also tested.

Micromedical's Chief Executive Officer, Dr John Woodard, said preliminary results indicated that the artificial heart functioned flawlessly for the implant period and that blood circulation was fully supported by the artificial heart. Dr Woodard described the results as "very encouraging", but said long-term testing was needed to ensure its reliable use by the first human, scheduled for 2001.

The new device is a small continuous-flow rotary blood pump developed as an alternative to pulsatile pumps. World-wide, about 4,000 pulsatile pumps have been implanted in humans to treat heart disease. These pumps are a temporary solution, taking over the function of the patient's left ventricle to restore normal levels of cardiovascular activity until a donor organ becomes available.

While the medical profession would like to use such devices as an alternative to transplant surgery, the existing pulsatile pumps are large, inefficient and expensive.

As a result, university research teams and major medical manufacturers throughout the world are attempting to develop a small, efficient, cost-effective alternative. In Australia, UTS and MMI began research on such a device in January 1997, aided by an Australian Research Council Collaborative Grant.

The research team now consists of 14 engineers and scientists, including some from the University of NSW, whose expertise covers a broad range of fields, including fluid dynamics, electro-magnetics, electronics, control engineering, materials technology, and haematology.

Dr Peter Watterson explained that unlike a conventional rotary pump, characterised by an impeller and a motor separated by a sealed shaft, the new prototype uniquely combines the impeller and motor.

"The fat impeller blades house magnets, which are driven around by electric currents. The blade edges are tapered so the impeller glides around on a cushion of blood, much like a bald tyre sliding on a wet road," Dr Watterson said. "This eliminates the seal and conventional bearings that could cause serious side effects for patients due to blood damage and blood clotting."

Professor Vic Ramsden says currently around 44 per cent of all deaths in Australia each year are directly related to heart disease. Of these, around 750 people die from congestive heart failure. People suffering from this condition could be helped by the pump.

"The number of cases of congestive heart failure in which this device could be used is 70,000 per annum worldwide," said Professor Ramsden.