A healthy mother struck down by mysterious heart disease stopped breathing and turned blue as her teenage daughter looked on, a coroners’ court heard on Monday.

Amelia McNally was just 49-years-old when she went into cardiac arrest at her home in Westacott Close, on the Elthorne Estate, Archway on June 13.

Her 13-year-old daughter Venetia called 999 saying “mummy is turning blue” but when ambulance crews arrived the fun-loving victim had already stopped breathing.

They rushed her to the nearby Whittington Hospital in Magdala Avenue but by this time she had been in cardiac arrest for an hour and doctors decided, even if she survived, she would suffer “significant brain damage and have a poor quality of life” and stopped attempts to resuscitate her.

She was pronounced dead at around 2.20pm, but experts can find no reason why a such a healthy woman with a normal heart should have died in such a way.

Ms Mcnally’s brother Gerald told the court earlier in the day she was struggling to breathe and had been vomiting what looked like “dirty water”.

He said: “She was full of fun, full of life. You would hear her before you saw her. She was very well liked – hundreds of people turned up at her funeral. If you needed a shoulder to cry on she was always there – unless it was me, she’d just tell me to get on with it.”

After a brief period of drug and alcohol abuse following her father’s death six years ago, Ms Mcnally has been completely clean for five years.

“She was quite proud of that,” said Mr McNally.

“She was getting her life back together and people who hadn’t seen her for a while always said how healthy she looked. She had been volunteering and working at rehabilitation centres helping other people.

“She even used alcohol free wet wipes – she wanted nothing to do with alcohol.”

Barbara Mckinnion, the first paramedic on the scene, said: “I found a woman in the bedroom, on her back on the bed. Her face was very dark.

“I moved her onto the floor and commence CPR. Three shocks were delivered”

Her toxicology report came back clean, and the post mortem and autopsy could find no reason behind her death

Recording a verdict of death by natural causes, the coroner said: “She died of cardiac dysrhythmia – heart failure – without any real explanation as to why.

“She was a healthy lady with a normal heart and nothing was identified which could cause her death.”