A British man has begun legal proceedings against the American manufacturers of a heart valve he claims contributed to the death of his wife.

Myrtle McCombe, 44, of Cookstown, Northern Ireland, died on 3 July 1998, two months after she had undergone an operation to be implanted with a St Jude Medical mechanical heart valve that had the latest modification of a coat of silver called Silzone.

Two years later her husband Billy received an autopsy report that said his wife had died because of a blood clot that had formed on the metal leaflets of the valve.

In 2000 St Jude Medical recalled all valves that had the coating after sponsoring a huge independent study. The Medical Devices Agency in the UK said the number of people who died shortly after the valve was implanted because of 'thromboembolic events' was unusually high. Around 37,000 valves were distributed worldwide, of which 1,300 were in the UK.

This week, five years after his wife's death, McCombe becomes the first Briton to join about 160 Americans who are taking legal action against St Jude Medical.

'It was months after the valve had been recalled that I found out. I want people who have had valves implanted to go and read their medical records to see if they had Silzone so that doctors can keep a closer eye on them,' McCombe said.

The Department of Health says that the risk associated with the valve mostly occurs shortly after the transplant.

Lawyers claiming negligence against St Jude Medical allege that the testing of the product may have been inadequate.

But a spokesman for the company said: 'Before receiving regulatory approvals, we conducted full and appropriate testing.'

An internal St Jude Medical memo suggests that Europe was used as a testing ground referring to 'the guinea pig continent of Europe.'

'This particular memorandum was prepared by a young sales employee who is no longer with St. Jude Medical,' the spokesman said.