What happens during cardiac ablation?

The causes of heart rhythm disorders can often be pinpointed to certain parts of the heart that are already damaged, possibly by coronary artery disease, for instance. This leads to abnormal electrical signals, and the heart gets out of sync. If the specific tissue in that area is ablated, it can no longer cause any interfering impulses, or they can at least no longer spread to the rest of the heart.

A special hereditary condition in the cardiac conduction system plays a role in other heart rhythm disorders: additional conduction pathways in the heart. If electric signals travel down these pathways, they can disrupt the heart’s normal rhythm and cause problems like making the ventricles beat too quickly. Catheter ablation is used to cut off these additional pathways in order to prevent that from happening.

A number of things need to be done before the heart tissue can be ablated using a catheter. Doctors will first confirm what the exact condition is. Then they will see whether there is an increased risk of complications, perhaps due to severe associated medical conditions.

That is why a number of examinations are carried out prior to the procedure, first and foremost an ECG and an echocardiography. Electrophysiology studies are also important, but are usually only done during the procedure right before the actual ablation is carried out.

You can discuss any unanswered questions you might have during pre-surgery consultation before you sign the consent form needed to have the procedure done.

This procedure is done in a catheter laboratory – which is usually in a clinic, but sometimes it is also performed as an outpatient procedure in a specialist cardiology practice. The skin around the groin is first disinfected and numbed with an anesthetic. The doctor then makes an incision there and inserts the catheter into a blood vessel. The catheter can then be pushed forward to the heart without causing any pain. A general anesthetic isn’t usually needed. But you can request a sedative if you would prefer.

The heart rhythm is monitored with an ECG during the procedure. The chest is usually scanned with an x-ray to see where the catheter is on a monitor. Often, this is not necessary, though. The position and orientation of the catheter can be monitored by a computer that creates a three-dimensional image from the previous heart scans.

An electrophysiology (EP) study starts once the tip of the catheter has reached the area that is thought to be causing the heart rhythm disorder: The doctor then sends bursts of electrical energy through the catheter and monitors how the heart tissue reacts to them. They can then work out exactly which parts of the heart need to be destroyed.

The step of actual ablation is typically done right afterwards. That usually involves electricity being applied to generate heat at the precise point where the scars should form. Technical terms for this procedure are high frequency or radio frequency ablation. Other techniques are sometimes used, too: For instance, extreme cold can be applied to the tissue (cryoablation).

The incision in the groin is usually sewn up and covered with a dressing. A special compression bandage may be used if needed.

You will then have to stay in the hospital for 12 to 48 hours for observation depending on your general state of health and heart disease. Your heart rhythm will be monitored regularly during that time. Other examinations such as another echocardiography usually have to be done and the stitches in the groin are removed before you can return home.

After the procedure, it's important to

• keep the area where the catheter was inserted clean and take care of the wound until it has healed,
• take showers rather than baths in the first week,
• avoid driving a car for the first two days,
• avoid more strenuous activities and sex for the first two days, and
• not lift any heavy objects and not ride a bike for the first one to two weeks.

It is important to see a doctor if pain, swelling or redness develops in the groin area, or if a bump appears where the catheter was inserted.

The electrical signals used for electrophysiology (EP) study and for the ablation itself can cause heart rhythm disorders. But the heart can usually be put back into a normal rhythm again straight away using the inserted instruments. Permanent heart rhythm disorders such as an AV block may also result. Other possible complications of cardiac ablation include:

• Bruising around the area where the catheter was inserted
• Bleeding after surgery
• Damage to the heart, blood vessels, or nerves
• Fluid build-up around the heart (pericardial effusion)