Thomas and Debbie Heavey's family holiday to Paris turned to tragedy when their eight-month-old daughter Kallista was suddenly struck down by a heart condition.

But just nine months after losing their beloved daughter, the couple are preparing for a charity walk and hope the money they raise will help prevent another family from going through the same nightmare. 

They will be taking part in a sponsored walk over eight bridges in central London, organised by the charity Cardiac Risk in the Young (CRY).

The charity says that every week in Britain, eight apparently healthy youngsters like Kallista die from undiagnosed heart conditions. 

The statistic will be symbolised by the eight bridges and eight kilometres the walkers have to cover during the event on July 15. 

Like many parents of children affected by heart conditions, Thomas and Debbie were unaware there was anything wrong with their daughter before that day in September. 

But hours after the first symptoms became apparent, the heart disease myocarditis had claimed Kallista's life.  Thomas, aged 42, of Wynbank Close, Miles Green, said: "It was totally unexpected.  Her breathing just became a lot shallower.  We had the doctor out, and took her to hospital.  We thought it was an allergy. 

"She seemed to be getting better but on the second day she suffered heart failure. 

"I'm still not entirely sure what it is - it's some sort of bug that attaches itself to the back of a virus and attacks the heart.

"It was such a massive infection there was nothing they could do at the hospital." 

Thomas and Debbie will be joined on the walk by their other children, Athena, aged eight, and four-year-old Xander. 

"Team Heavey", as they call themselves, will also consist of various other members of their extended family and friends, and they are aiming to raise hundreds of pounds for CRY.

Thomas added: "Originally it was only going to be my wife, our two other kids and myself doing the walk, but there's been so much interest. 

"The money that's raised will help buy equipment and fund research into screening, so doctors are better able to identify children who are most at risk.  If they can treat heart conditions early, it can make a big difference. 

"That's why we're doing it, why we want to raise as much money for CRY as we can.  If we can prevent another family going through what we've been through, then that would be fantastic."

Wolstanton teenager Nathan Butler died suddenly from a rare heart condition last February at the age of 16, and since then his family have helped raise more than £7,000 for CRY. 

Nathan's mum Angela said: "CRY has just spent £200,000 on research into conditions like Nathan's, and the money we raised has helped to pay for that. 

"It is a fantastic organisation.  It's not only the screening work they do, but also the bereavement support they offer to families.  We've had a lot of help from them." 

The Heavey family have set up a website to make it easier for people to sponsor them.  To support Team Heavey, follow the link at www.thisisthesentinel.co.uk/usefullinks

Leave your tributes to Kallisata at www.thisisthesentinel.co.uk/yourtributes