Mr Gibson suffered a cardiac arrest while sleeping on the sofa.
A 39-weeks pregnant mother scheduled for a planned Caesarean section, was forced to give her partner chest compressions after she found him unresponsive. Rebecca Moss recalled telling her partner, "Wake up, it's baby day", only to find Thomas Gibson, 40, lying dead after doctors misread an abnormal heart scan.
Mr Gibson suffered a cardiac arrest while sleeping on the sofa.
Minutes later, an ambulance arrived and pronounced him dead, Stockport Coroner's Court heard. Hours later, Ms Moss gave birth to their daughter, Harper, in hospital.
At the inquest into Mr Gibson's death, a hospital doctor said he had misinterpreted an electrocardiogram (ECG) scan carried out 11 days earlier, when he had gone to A&E suffering from a severe stomach bug, Sky Newsreported.
Ms Moss recalled that she woke up at 5.15 am on June 7 last year, and went downstairs.
She said: "Tom was asleep on the couch. I was trying to cheer him up and was saying 'Wake up, it's baby day'.
"Tom didn't respond, so I went over to the couch to give him a kiss. He was lying in his usual sleeping position.
"When I touched him, he was cold and stiff. He wouldn't wake up.
"I called 999 immediately. They asked me to pull Tom on to the floor and perform chest compressions. I started chest compressions until the ambulance arrived.
"The shock, trauma and not to mention the physical exertion of having to pull Tom off the couch and perform chest compressions at 39 weeks pregnant was overwhelming."
Ms Moss gave birth to her daughter, Harper, later the same morning.
Talking about Mr Gibson, Ms Moss described him as ""caring, charming and funny" and was excited to become a father.
Ms Moss told the news outlet that she will be celebrating her daughter's first birthday but without her father.
"He won't be there for any of her birthdays," she added. "He won't ever be there on Christmas morning, and he won't be there on Father's Day. Harper will instead visit her dad's grave when she's old enough to understand.
"We say good night to his picture every night before bed and she has a quilt which has been made from his favourite jumpers.
"Tom will live on through his daughter but that doesn't change the fact that he should still be here with us today."
Ms Moss told the inquest that Mr Gibson worked in a timber yard and was physically fit but had been suffering from a stomach bug. He suffered from cramps and diarrhoea, for around three weeks before his death.
He attended A & E at Wythenshawe Hospital on 27 May last year and was seen by Dr Oliver Handley. The doctor found his ECG trace showed signs of an abnormality and referred it for a second opinion to a more senior medic.
Dr Thomas Bull said the ECG scan was likely to be an abnormality which he described as an intraventricular block, that is "not an uncommon finding" and not clinically "significant" without other heart-related symptoms.
"I advised if there's no heart symptoms generally then that would not require any investigation at this time," Dr Bull said.
Analysis later found the ECG identified a complete heart block, also known as a third-degree heart block.
Dr Bull added: "I can see now, in retrospect and in hindsight, there is abnormalities over and above those I could see present."
Mr Gibson was discharged from hospital with no immediate treatment.
He was asked to return in a week if his health didn't get better. But unfortunately he was found dead 11 days later.
Lawyers for Mr Gibson's relative said that Manchester University NHS Foundation Trust has made a full admission of liability that it provided negligent medical care to him in the days before his death.