A PROJECT to help patients with diseased hearts is on hold while the Hospital Authority decides whether to buy a state-of-the-art-laser after returning one it borrowed. In April, Grantham Hospital announced it had become the first centre in Southeast Asia to use powerful laser beams to cut channels in patients' hearts and improve blood flow. The territory's leading heart disease centre has already treated more than 10 patients and is understood to have another six waiting to undergo the operation. But sources said the $10 million machine, loaned to the Aberdeen hospital free for a year by its developer, was removed last month. The hospital is understood to be negotiating with the American developer for a new loan, and the Jockey Club has been approached for sponsorship. Privately owned St Teresa's Hospital is considering buying the laser machine, according to administration manager John Ng Sai-cheong. 'The machine has been delivered to our hospital but it hasn't been used. The company will send its overseas engineer to check on the machine very soon, then our hospital should decide if we will buy it,' Mr Ng said. Meanwhile, a Hospital Authority spokesman said a decision would be made on whether to buy the machine next financial year, after April 1997. 'The authority has to evaluate very carefully the effectiveness of the machine as it is costing the taxpayers money,' the spokesman said. 'Besides, the conditions of the six patients are not so bad that they need to have the surgery immediately.' The transmyocardial revascularisation machine offers hope to patients unable to have bypass surgery or angioplasty. Queen Mary Hospital cardiologist Dr David Ho Sai-wah said the laser treatment was the only possibility for a patient whose blocked arteries had become too narrow and too diffused. The laser creates channels in the heart wall, boosting blood supply to heart muscles which have been deprived of blood because of blockages. Conventional bypass surgery lasts six hours but a laser operation takes only two, and there is no need for the patient to be on a heart-lung machine while in surgery. Coronary artery disease is the No 1 killer in Hong Kong, accounting for more than 10 per cent of the 30,222 deaths in 1993.