THE future of the region’s children’s heart units is in fresh doubt as they are poised to be ordered to meet tougher standards – or close.

Health chiefs have drawn up new rules to decide which centres should remain open, to settle a bitter, decade-long controversy which, they admit, threatens safety and quality.

In theory, all ten units – including at Freeman Hospital, in Newcastle, and at Leeds General Infirmary – could survive the shake-up, proposed by NHS England.

However, a fresh battle for survival is likely, with the fresh standards including:

* That each unit has at least four heart surgeons, to provide treatment around the clock and cover for staff absences.

* That every surgeon carries out at least 125 operations a year, averaged over three years, to ensure they build up expertise in the complex procedures.

Tonight (Monday), both Freeman Hospital and Leeds General Infirmary said they had only three surgeons, although Leeds said funding was already in place for a fourth.

Moreover, only 247 child heart operations were carried out in total at the Freeman in 2012 and just 336 at Leeds – when a minimum of 500 would be required at each unit.

Across England, there were 4,716 operations, but four-surgeon teams at each of the ten existing children’s heart centres would require at least 5,000.

Under the plans, which will be discussed at autumn events in both cities, units will be given three years to beef-up their capacity, if necessary.

If they are unable to do so – or cannot meet other standards to improve the experience for patients – they could be forced to close, or merge with other centres.

A spokeswoman for NHS England said: “There is a general consensus that four surgeons is the minimum, to provide enough cover when someone is on holiday or called away on urgent business.

“And 125 operations is the minimum each surgeon needs to carry out each year in order to keep their skills up to date and to ensure they are working on the most complex cases.”

The fresh consultation comes 15 months after Health Secretary Jeremy Hunt scrapped plans to concentrate surgery in seven centres and axe three others – including Leeds.

To the jubilation of campaigners in Leeds, Mr Hunt accepted the conclusions of an independent panel that the closure plan was “based on a flawed analysis”.

However, concerns about babies dying unnecessarily - because doctors carry out too few operations to build up the necessary expertise – date all the way back to 1989.

Now families, charities, MPs and hospitals have until December 12 to make their views known, including at the events in Newcastle (October 16) and in Leeds (November 3).

In a statement, Leeds Teaching Hospitals NHS Trust said: “We currently have three surgeons undertaking children's heart operations and have funding in place for a fourth if they are required.

“Our surgeons all currently do in excess of 125 cases each every year.”

Sir Leonard Fenwick, chief executive of Newcastle upon Tyne Hospitals NHS Foundation Trust, said it already had plans to expand facilities at the Freeman.

He added: “Newcastle has a longstanding, demonstrable track record of international standing with ‘best in class’ outcomes involving the most complex and high risk cases referred to us.”

The fresh review has been made more complex by a decision to include services for adults – as well as children – with congenital heart disease.

The Health Secretary himself highlighted the huge challenge in making decisions based on mortality data that was “extremely difficult to interpret properly”

To avoid new turf wars, centres will be expected to work together more closely, with patients treated in one unit, but cared for afterwards in another – perhaps closer to home.

The other expected standards include communication with patients and their families, the transition moving between child and adult services and providing other healthcare services.

The consultation document is available at http://www.england.nhs.uk/ourwork/qual-clin-lead/chd/