A DOCTOR gave a new heart monitor a trial run - and discovered he needed a life-saving operation.

David Harrison was demonstrating the new device when he found out he had an abnormal heart rhythm.

After the shock reading, he went to see a heart specialist who referred, him to Leeds General Infirmary where he underwent open heart surgery.

Dr Harrison, a GP at a group practice near Selby, got the early warning that saved his life after receiving a C.Net2000 monitor for a trial period from manufacturers keen to show off their new device.

After a 24-hour self-demonstration of the monitor, he downloaded the results on to a computer which showed an irregular heartbeat and pulse.

He said: "I knew the symptoms could be associated with heart disease and went straight on to warfarin, an anti-coagulant, to reduce the risk of a stroke.

"I then went to see a specialist at York District Hospital. He took a scan, which revealed my heart was enlarged and had gone into failure. The mitral valve had disintegrated."

Dr Harrison, 66, had his mitral valve replaced by open heart surgery. The valve allows the blood to flow from the left atrium into the left ventricle, but prevents blood flowing back into the atrium.

If the condition had gone unchecked, it could have proved fatal.

The GP, who now works part-time in the Sherburn-in-Elmet surgery's administration office, said: "The machine saved my life.

"I had been tired and breathless but put it down to my age. I had no idea I had a heart problem.

"I was only demonstrating the monitor to prove it was not obtrusive."

Father-of-three Dr Harrison, of Kirkgate, Sherburn-in-Elmet, added: "This monitor has the ability to separate the urgent cases from the not-so-urgent cases, allowing those most at risk to receive priority treatment."

No larger than the average wallet, the machine is worn by the patient for up to 24 hours while it takes heart readings via three electrodes fixed to the patient's chest.

C.Net2000, designed and developed by British company Cardionetics, has already received recognition at the BBC Tomorrow's World awards.

Updated: 11:15 Wednesday, April 10, 2002