Where the cath labs are located - and what they do
A cath lab is part of a hospital's cardiac department, caring for patients with heart disease.
There are around 20 cath labs in Dublin and several more in hospital-based cardiac centres across the country.
A cath lab is both an examination and treatment room, which allows diagnostic and interventional procedures to be carried out.
Patients who experience chest pain caused by blockages in the arteries to the heart, or those who need a pacemaker to correct abnormal heart rhythms, are referred there.
Tests and procedures are carried out in the cath lab on emergency and waiting-list patients.
A cath lab is staffed by a team of different specialists, usually led by a cardiologist.
This is where various procedures are carried out including ablation, angiogram, angioplasty and implantation of pacemakers.
A patient who presents with a heart attack will need to have an artery opened to allow blood to flow to the heart muscle.
Cardiologists in the Waterford hospital estimated last year that it would take 499 hours to tackle the backlog of patients which had built up and depended on its single cath lab.
This was based on opening for an extra eight hours a week as recommended in the Herity report, which said there was no need for a second cath lab.
Since then the waiting list has fallen, due to patients being sent to Cork University Hospital and a private cath lab.
But doctors warn the list is now building up again.
They remain concerned about the risks to emergency patients who present out of hours when the cath lab is shut.
The patients have to be referred to Cork University Hospital and it may be a race against time.
The mobile cath lab is due to open in September.