Moving children's congenital heart surgery from Belfast to Dublin will put lives at risk, parents have warned.
Relatives expressed outrage after Northern Ireland's health authorities recommended operations for youngsters with birth defects should take place in the Republic using enhanced north/south transport links.
The decision will need to be approved by Stormont Health Minister Edwin Poots.
Samantha Marshall, whose son Tom, aged two, has a condition, said: "Four to five children a year will not survive a journey to Dublin."
The change was intended to ensure that doctors carry out enough procedures to keep up their skills, but parents claimed it will put their children at risk.
The Health and Social Care Board, which commissions services in Northern Ireland, examined options for providing the relatively rare operations, including using hospitals in England as well as Our Lady's Children's Hospital in Crumlin in South Dublin.
Board chief executive John Compton said: "It is a fact that uncertainty has hung over those services now for a very protracted period of time, well before the establishment of this organisation.
"It is very important that we get to the point where that uncertainty is removed."
Congenital heart disease is the most common birth defect in Northern Ireland, with around 250 babies born with the condition every year, according to the Children's Heartbeat Trust charity.
Centres must perform a minimum of 400 children's surgical procedures each year to maintain skills, a report said, but Belfast falls short of that number and the volume is decreasing.
The health board's decision followed another review that said, while safe, undertaking heart surgery at the Royal Belfast Hospital for Sick Children was no longer sustainable because of the small population served and lower activity level of medics than recommended by professional organisations.
The board decided children who required planned surgery should travel to Dublin, with an improved transport network from Northern Ireland to help meet the three hour timeframe for emergency surgery. Support cardiology services in Northern Ireland will be enhanced.
One parent asked board members: "Is it the health minister or the commissioners who will take responsibility when a child dies?"
Options ruled out included splitting surgery between Belfast and Dublin or involving hospitals in Great Britain.
Parents and members of the Heartbeat Trust campaigned to retain children's heart surgery in Northern Ireland.
Executive officer Sarah Quinlan said: "Any move which sees the end of children's heart surgery in Belfast puts at risk the lives of children born in Northern Ireland whose heart condition has not been diagnosed during pregnancy and who require emergency life-saving intervention.
"Shifting surgery to Dublin requires 24 hours, seven days a week specialist transport services which are not currently in place, have not been tested and are vulnerable."
The trust's minority report was submitted to the board during a meeting punctuated by emotional interjections from concerned parents.
Health Minister Edwin Poots said he intended to hold further discussions with counterparts in the Republic and explore the scope for flexibility in the location for the future delivery of the service without compromising patient safety.
"My key priority in all of this is to ensure the delivery of a safe and sustainable service for these vulnerable children," he added.
The Republic's health minister Dr James Reilly told the BBC: "I am quite happy that we will have a capacity here in Dublin to look after children from the North of Ireland."
Belfast health trust, which runs services at the Royal, expressed concerns about retaining surgical skills in Belfast and said the city's cardiologists will have sessions in Dublin. It welcomed today's outcome.