A woman who suffered repeated blackouts died after doctors failed to diagnose her irregular heartbeat, despite it being indicated in tests.
Rose Fuentebaja from Stratford-upon-Avon had been in hospital for a week when she suffered a cardiac arrest and died in June 2017.
Doctors at Warwick Hospital mistakenly believed the issue to be neurological.
West Midlands Ambulance Service and South Warwickshire NHS Foundation Trust have admitted failings in their care and agreed a £1m damages settlement with her widow following legal action.
Mrs Fuentebaja moved to the UK from the Philippines in 2001 with her husband, Darrel Fuentebaja.
"It was a really traumatic time when my wife died," he said.
"As a nurse herself she was really committed to helping others and she helped to save many lives.
"Unfortunately, when the time came when she needed that help, she was failed and it cost her life."
Mr Fuentebaja said he went into a deep depression for about a year and worried what would happen to his children if anything happened to him.
"I was left feeling very angry and bitter about that, and the mistakes that were made, and that is why I pursued legal action for her. I wanted justice for her," he said.
As part of the legal case, led by Elizabeth Maliakal of Hudgell Solicitors, West Midlands Ambulance Service admitted breaching its duty of care as paramedics failed to identify potential cardiac issues, despite an echocardiogram (ECG) showing disturbances and her loss of consciousness.
It also admitted that Mrs Fuentebaja should have been advised to go to hospital that day.
Mrs Fuentebaja's first ECG test showed disturbances in her heartbeat, but ambulance workers recorded this as being related to anxiety and she was told she did not need to go to hospital.
South Warwickshire NHS Foundation Trust admitted that failing to refer Mrs Fuentebaja to cardiology and failing to place her on constant heart monitoring was also a breach of duty on its own part.
It admitted that had this happened, the 40-year-old nurse would have been correctly diagnosed and treated, and even if she had still suffered the cardiac arrest, she would have received swift defibrillation and resuscitation, and would have survived.
Mrs Maliakal called the case "incredibly tragic and heart-breaking".
She said: "Mrs Fuentebaja’s death was wholly avoidable. Had she been given appropriate treatment and care she would still be with her family today, but she was let down by two separate health providers.
"The missed opportunities to provide timely treatment led to the loss of a much-loved mother, wife and daughter who was the main provider for her family."
A West Midlands Ambulance Service spokesman said: “We would again like to apologise to the family of Rose Fuentebaja and offer our condolences.
“The trust undertook an investigation into the incident, which we have learned from. As a result we have implemented a number of changes based on the findings.
“We will continue to do all we can to try and stop something like this ever happening again.”
A spokesperson for South Warwickshire University NHS Foundation Trust said: "We express our heartfelt condolences to Rosalie’s family and friends.
"At the time of her death in 2017 we thoroughly investigated any missed opportunities and following that implemented learning across the organisation.”
