A heart transplant survivor has died just hours after giving birth to her first child, despite showing no signs of illness.

Meg Johnson, 31, gave birth to daughter Eiliee Kate, in Vanderbilt University Medical Center in Nashville on Tuesday at 2:40am, with her husband by her side.

After an uncomplicated birth, Johnson and partner Nathan sat together for hours with their newborn burping her, holding her and even posting a photo on Instagram.

But, at around 9am, the new mum began to feel unwell, and within a matter of minutes doctors said they were unable to save her. She died just before 10am.

Although Johnson had undergone a heart transplant seven years ago after contracting myocarditis – a disease of inflamed heart muscles – doctors said they do not believe this was the cause of her death.

While medical professionals try to establish the cause, a GoFundMe account has been started by friends of the family with the aim of raising $400,000 (£308,000) for widowed Nathan and daughter Eilee.

The page has managed to raise an impressive $330,000 (£254,000) in just one day.

Josh Wilson, one of Nathan’s best friends who started the fundraiser wrote: “Nathan is devastated. There are no words for this, so I won't really say much more. Here is what I know. Nathan is a wonderful man and an amazing father. He loves his daughter dearly.

“Let's raise enough money for Nathan to get off the road for at least 6 months. Let's cover his bills and meals so he doesn't have to think about any of that. Let's sleep over at his house and feed sweet Eilee so Nate can rest.”

As family and friends rally around, the generosity of strangers means that Nathan, a Christian musician who produces his own music, will be able to take some time off performing on the road and care full time for his daughter.

Staggered by the speed in which large sums of money have been donated, they hope the funds could even be enough to start a college fund for little Eilee.

While Meg’s cause of death remains unclear, women who have suffered myocarditis, as she did, are at high risk of peripartum cardiomyopathy (PPCM), a rare form of heart failure.

PPCM occurs during the last month of pregnancy or up to five months after giving birth but as symptoms are very similar to typical third-semester problems, it can often be hard to spot.