Ablation Treatment of Heart Rhythm Abnormalities

What is ablation?

Ablation is the destruction of a part of the body by surgery, heat, severe cold, or chemicals. In the heart, ablation usually refers to destruction of small portions of tissue called conduction pathways. These pathways carry electrical impulses that cause the heart to beat in an organized way. When they are not working properly, heart rhythm disturbances can result. Ablation treatment can help fix these disturbances.

What is the heart’s conduction system?

The conduction system in the heart is a circuit of tissue bundles that act as wires. These “wires” carry an electrical impulse down a defined circuit that causes the orderly contraction (squeezing) of heart muscle. The tissue pathways that form the conduction system are in both the upper and lower chambers of the heart.

Abnormalities in the conduction system can result in heart rates that are too fast, too slow, very irregular, or a combination of these. The abnormalities may be present from birth or may be caused by disease.

When is ablation necessary?

Many drugs are available to treat abnormal heartbeats. Sometimes, however, drugs cannot be used because of side effects or lack of good results. For some heart rhythm abnormalities, a better treatment is to interrupt, or ablate, part of the conduction system. Successful ablation does away with the need for and the expense of taking drugs.

How is ablation done?

To successfully interrupt an abnormal conduction pathway, your doctor needs to know where it is in your heart. Fortunately, the structure and location of the conduction system is similar in everybody. Your doctor already has an idea of where to look.

The first step is to identify the abnormal tissue pathway in the heart. This is done by inserting a catheter, which is a small tube, through a vein in your groin. You will be given a shot to numb the area where the catheter is inserted. You will feel very little pain. The tip of the catheter is guided by x-ray to the proper position in your heart. To make sure of its position, your doctor will use the catheter to record electrical signals from within your heart. The procedure may last several hours and may require using several catheters. You will remain awake during the procedure, but you can be sedated if you wish.

Once the catheter is in place, a small electrode at the tip is used to deliver high frequency radio waves. The radio waves cause the tissue surrounding the electrode to get so hot that it is destroyed. This permanently interrupts the tissue pathway and changes the way the impulse travels in your heart. Your heart heals the damage from the ablation by forming a small scar.

Your doctor will likely repeat the recording of electrical activity from within the heart and, when satisfied, remove the catheter. After several hours of recovery, you will be able to resume normal activity. In most instances, you will need no further treatment.

What are the complications?

Aside from a little pain in the groin, complications are rare. Bleeding sometimes occurs where the ablation catheter was put into the vein. The bleeding rarely causes serious problems. Ablation sometimes will destroy more conduction tissue than desired and cause complete heart block. Heart block may result in a very slow heartbeat. If this happens, an artificial pacemaker must be inserted, which usually produces good results. Rarely, the heart rhythm abnormality recurs after the ablation, and the procedure is repeated.

Information obtained from GE Medical Systems; authorization given to reproduce on HCNW web site 9/02.
Written by Donald L. Warkentin, MD
Published by McKesson Clinical Reference Systems.
Copyright © 1997-2002 McKesson Health Solutions LLC. All rights reserved.
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.