The mother of a nurse who died of shock when her alarm clock rang is spearheading a nationwide campaign to raise awareness of the condition which claimed her daughter's life.
Lisa Jane Browne was 27 when she died of sudden heart failure in 1998.
Her mother, Doreen Harley from Connah's Quay, was in Cardiff last week to launch the campaign and to raise awareness of the risks of sudden cardiac death.
Lisa had a rare condition called Long QT Syndrome, which was never diagnosed.
Doreen said: "We want people to know that we can offer support, counselling and the screening of other family members who might be at risk from Long QT Syndrome.
"We are sending out copies of the postcard to all MPs and AMs and are hoping an all-party policitcal group will be formed to support our cause.
"Not a day will go by that we will ever forget the happy memories that we have of Lisa.
"Although her life was so tragically cut short, we are so proud to have had her for 27 years."
In the last three years of her life Lisa was suffering with tiredness, chest pain and palpitations but was only given anti-depressants by her GP.
Since Lisa's death her sister Rachel has tested positive for the condition and has been fitted with a pacemaker, and erring on the side of caution Rachel's sons Jack and Adam are treated with beta blockers.
An emotive new postcard featuring photographs of 12 people from Wales, including Lisa, who have died of undetected heart conditions, was unveiled at the launch organised by CRY (Cardiac Risk in the Young.)
Alison Cox, the charity's founder said: "We need to keep up the pressure and get support from as many MPs as possible to ensure we are doing everything we can to prevent other families from experiencing similar tragedies."
Sudden cardiac death is the terms for heart conditions which affect fit and healthy people and can result in a spontaneous death if not reacted.
For more information on sudden cardiac death, call CRY on 01737 363 222 or go to http://www.c-r-y.org.uk
