Medical

What to expect in a cath lab

Cath lab

The cath lab, also known as a catheter laboratory or cardiac catheterisation laboratory, is part of a hospital's cardiac department. Find out what happens there.

A cath lab is where tests and procedures including ablation, angiogram, angioplasty and implantation of pacemakers / ICDs are carried out. Usually you'll be awake for these procedures. A cath lab is staffed by a team of different specialists, usually led by a cardiologist. A cath lab shouldn't be confused with an operating theatre, where you would have surgery such as a heart bypass operation, under a general anaesthetic.

1. Getting ready

Before you go into the cath lab, you'll change into a gown and a small plastic tube will be inserted into your arm. This tube – a cannula – is there in case you need any medicines during the procedure. You will discuss the procedure with your doctor and sign a consent form, before being taken to the cath lab and asked to lie on an x-ray table.

The table has a mattress for your comfort, as you may be there anywhere between 30 minutes and a few hours, depending on what procedure you are having and how long it takes. You will be connected to an ECG machine so your heart rhythm can be closely monitored. Your vital signs, including blood pressure and blood oxygen levels, will be monitored too.

Sterile paper towels will be draped over you to create a clean environment and reduce the risk of infection. If you are having a general anaesthetic so you are asleep during the procedure (this sometimes happens before an ablation, but not always), an anaesthetist will administer this. Pacemakers are fitted under a local anaesthetic with sedation, so you’ll feel very sleepy.

2. The procedure

For angiogram, angioplasty or ablation, the skin at either your groin, collarbone or neck will be cleaned using a special solution, before a local anaesthetic is administered by injection to numb the site. The cannula is then inserted, and the catheters are passed through the vein or artery to your heart, using x-ray guidance.

What happens during an angiogram?

During an angiogram, a special dye will then be passed through the catheter and a series of x-rays will be taken. You might feel a hot, flushing sensation from the dye. The dye will show up any narrowed areas or blockages in the artery on the x-ray.

Read more about angiograms and watch a video.

What happens during an angioplasty?

During an angioplasty, the catheter will be directed until its tip reaches a narrow or blocked section of coronary artery. A balloon on the end of the catheter is then gently inflated so that it squashes the fatty plaques - or deposits - against the artery wall, widening the artery and allowing the blood to flow more easily. Often a stent, a thin tube of expandable mesh, will be inserted to reinforce the walls of the artery.

Read more about angioplasty and watch a video of the procedure.

What happens during an ablation?

During an ablation, once the tips of the catheters are in place, the electrical activity in your heart can be recorded. Sometimes it is necessary to trigger the arrhythmia to identify what the problem is and where it is coming from, so the cardiologist knows which area to ablate. This process is called an electrophysiology study, or EPS. The ablation catheter is then passed into the heart to deliver the treatment.

Read more about ablation and see the video of Anne's ablation.

What happens during a pacemaker or ICD insertion?

For pacemaker or ICD implantation, a small incision is made in the chest and the lead or leads will be passed into the heart, using a vein as a guide. The lead(s) will be implanted in the heart, using x-ray imaging to show the heart so they can be put in the right place. The leads are then connected to the pacemaker and the pacemaker is inserted into the incision and implanted under the skin. The wound is then closed using dissolvable stitches. 

Find out more about pacemakers and watch a video of one being implanted.

3. Testing for success

During an angioplasty, the x-ray imaging will show whether the blood flow has been restored. If the artery was badly blocked, you'll often start to feel better as soon as the procedure is completed.

During an ablation, after the area has been ablated, the cardiologist will check to see if the arrhythmia can still be triggered. If it can, they will continue finding and ablating problematic tissue. In procedures to treat AF, the goal is to build a ‘fence’ around the trouble spots in the heart, so the cardiologist will test to check the ‘fence’ is intact at the end of the procedure. 

During pacemaker implantation, the ECG reading will show that the device has started to work straight away. The cardiologist will also check that the leads are secure.

4. What happens afterwards

After the procedure, the catheter will be removed and you might have a small amount of bleeding. If so, the nurse or doctor will press on the cut for a little while or insert a plug called an angioseal.

You might be asked to stay lying down afterwards - probably for just a short time after an angiogram, or a few hours after an ablation.

You can usually go home the same day as your angiogram. If you've had an angioplasty, ablation or pacemaker or ICD implantation, it could be the same day or the next day. If you've had an emergency angioplasty for a heart attack, you will need to stay in hospital a little longer.

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