The 29-year-old suffers from a rare genetic condition, Long QT syndrome, which means that loud noises could stop her heart.

But a specially-adapted pacemaker fitted earlier this year is helping make her life easier.

She found out this month that it had already saved her life once - by jump-starting her heart after it stopped when she was awoken in the night by her son Adam screaming.  The device also helps to regulate her heartbeat.

She only found out about the incident at her regular check-up at St George's Hospital, London.

Rachel is still coming to terms with what has happened and the consequences of Long QT syndrome, which has already claimed the life of her sister Lisa Browne.

Lisa, who trained as a nurse in Coventry, died four years ago when she was awoken by an alarm clock.

Doreen Harley, Rachel's mum, said the last few years had been very upsetting, particularly following Lisa's sudden death in 1998.

"Rachel is finding it difficult to accept everything at the moment.  It has been a very difficult year. She has gone through an awful lot of stress" she said.

"It has been very stressful for us too.  We have lost one daughter and if Rachel had not had the operation to have the ICD pacemaker fitted we would have lost her too."

After Lisa's death Doreen and husband Terry were tested for Long QT with the help of charity CRY - Cardiac Risk in the Young.

Terry was found to have the little-known condition.

It took Rachel a while to decide to be screened and in January this year she agreed to testing.  It was found that she also suffered from Long QT syndrome.

Not only that but Rachel's eldest child, Jack, aged six, was also found to have the syndrome.  Doctors believe medication could control Jack's disorder.  Adam her other son has been screened but his results aren't back yet.

Mrs Harley said the family wanted to raise awareness of Long QT and similar conditions and encourage screening.

At the moment CRY believes between four and eight young people die each week from sudden cardiac death.

"A lot of these deaths could be prevented.  We don't want to alarm anyone - we just want to alert people to the fact that screening can save lives.  If a disorder is diagnosed it can be managed." said Doreen.