New proposals have been put forward in an effort to resolve a long-running row about the congenital heart surgery in England.
The latest review, which has taken two years, suggests networks of surgeons working as teams across hospitals.
These fresh proposals will be considered by NHS England’s board later this week.
It warns that not all centres currently doing this work can meet the new standards.
Previous efforts to reduce the number of units performing delicate heart operations on very sick children in England led to acrimony.
They were eventually derailed, after being challenged in court and questioned by a panel of independent experts.
The government decided two years ago that the public had lost confidence in the reorganisation.
This new review has examined surgery for adults as well as children born with heart defects.
It suggests cardiac surgeons should work in teams of at least four, with each of them doing more than 125 of these highly specialised operations every year.
The review warns that not all heart units are currently working in this way.