In the middle of the night, Nicky Clisby's boyfriend started to snore. It wasn't unusual. Half asleep, she nudged him gently. The tone of the snoring changed and it concerned her. She turned on the bedside light to see his lips were blue.

Nicky acted quickly but by the time she had rushed to the phone and back, it was too late. She couldn't find a pulse.

The paramedics who dashed to their Ewelme cottage did everything they could. A defibrillator to jump-start his heart was used, but to no avail. Shane Kneath, a fit, active and healthy 37-year-old, was already dead.

The death certificate states that cardiac arrest, caused by left ventricular hypertrophy - an enlarged left heart ventricle - was to blame. Shane's heart was enlarged, caused by a narrowed valve which made the organ work twice as hard to get blood pumping through.

It was a ticking timebomb. The valve condition could have been genetic but it had gone undetected and it killed him.

"There is nothing in the world to prepare you for something like this," said Nicky, 29. "Shane was fit. He'd done triathalons and been a policeman before a knee injury forced him to leave. He'd been in the Navy and had a full medical there when he was 17. They found a trace of a heart murmur but it didn't stop him passing.

"He had another medical when he joined the police and, in 1993, he had a general anaesthetic for a knee operation and still it wasn't picked up. He's the last person you would expect to suddenly die."

Nicky's life was changed forever by the events of the night of January 29, 1997.

"I've been told since that the snoring probably wasn't snoring at all but air coming out of his lungs. His heart had certainly stopped by then and it only takes about four minutes for the brain to die.

"I kept thinking if I'd done something he might be here now, but I've had to accept that by the time I'd rung for the ambulance nothing could have been done.

"I've done a first aid course since then, so I'd know what to do if there was time.

"But they did say there was practically no chance of me reviving Shane, given the enlarged state of his heart."

It was a terrible end to a relationship that started with such promise.

Nicky, who trained as a fine art valuer and auctioneer, went to Australia on a three-month holiday of a lifetime.

There she met Shane, who was also seeing the world after becoming disillusioned with his job as a private investigator after leaving the police. "I went for three months and ended up staying for another seven. Together, Shane and I saw some fantastic places."

As they walked around New Zealand and Australia they talked, planning their future. Their dream was to go into the antiques business together. Nicky would source the pieces of furniture and Shane would restore them.

On their return, the couple moved to Oxfordshire together and rented a place in Watlington until they bought their cottage in Ewelme, near Wallingford.

In September 1996, Shane enrolled on an antique restoration course at Rycotewood College in Thame, hoping to realise their dream.

It was never to be.

Early in January 1997, Shane complained that he felt a bit tired and needed to step up the exercise he was doing. He cycled to Thame at least three times a week and the couple took their short-haired pointer Zebedee on long walks, but he wanted to do more.

"Shane's father died of heart disease when Shane was nine. He was very aware of it and didn't want it At first Nicky thought he was snoring. But when she turned on the light, Shane's lips were blue to happen to him. He kept himself fit and active and ate healthily. He put his father's problems down to the lack of awareness about diet and fitness in the 1960s," said Nicky.

Today, Nicky has a new job and a new life. She works for the Anglia and Oxford Health Region as a workshop co-ordinator, helping both medical and non-medical professionals appraise research and act on the evidence.

She lives in the same cottage but has a new man in her life and has pulled herself out of her grief to move forward.

"It's early days. I will never forget Shane but he'd be the last person who would want me to stand still.

"I was on sleeping pills for a year and I saw a bereavement counsellor, which helped a lot, and now it's time to move forward," she said.

"My new boyfriend is very supportive. Obviously it's a difficult situation but he is fully supportive of me."

Part of Nicky's healing process will be a ten-day, 110km sponsored hike for the British Heart Foundation across the Great Wall of China, which she will undertake at the end of October.

She needs to raise £2,000 to take part, of which £1,125 is guaranteed to go towards the BHF's work. She has already paid a £250 deposit herself.

"I'm doing it to raise money for heart research, education and patient care. Through Shane, I have got a reason for the walk, but you must never be complacent about life.

"If someone like Shane can die like that, then anyone can. * Heart disease: the blunt truth

Heart and circulatory disease kills more people in the UK than any other single cause. There's a new victim every two minutes.

Premature death (under 75) from heart and circulatory disease in the UK kills the equivalent of five Jumbo jets crashing every week. That's one in five men and one in ten women.

43 per cent of all deaths are from heart and circulatory disease.

300,000 people in the UK have a heart attack each year. About half of these are fatal. Around three per cent of adults suffer from angina and half a million people have heart failure.

About 123m working days are lost each year due to heart and circulatory disease.

Story date: Saturday 27 February

Converted for the new archive on 30 June 2000. Some images and formatting may have been lost in the conversion.