Overview
Catheter ablation is a last resort for treating arrhythmias, particularly Atrial fibrillation,. In this procedure, the pathways from the area of the heart causing the arrhythmia are damaged with heat waves so electrical impulses cease to transmit.
It is an invasive and time-consuming procedure, and arrhythmias are not necessarily life threatening; that’s why it’s only a last resort. However, it does cure the arrhythmia, while medications only treat it.
Detailed Description
The problem
The heart has four chambers, two upper (atria) and two lower (ventricles). The atria and ventricles work as a team. When the heart beats, blood flows from the atria to the ventricles. From the ventricles it flows to the rest of the body, carrying oxygen and nutrients and picking up waste. In a healthy heart, the sinoatrial node (S-A node), situated in the right atria, acts as a natural pacemaker, sending electrical signals that tell the heart to contract.
Some types of arrhythmias, particularlyatrial fibrillation, are caused when another part of the heart tries to take over as pacemaker. Catheter ablation causes scar tissue to form on the pathways leading from the part of the heart that is sending the unwanted messages. Ablation might also be used to destroy the actual part.
The procedure
This procedure will take 3-6 hours, and substantial recovery time. Your arms and legs may be restrained for your safety. Because of the length of the procedure, you may have a catheter inserted to drain your bladder.
First, the doctor will administer an electrophysiology study (EPS). That means s/he will reproduce the arrhythmia so that s/he can evaluate it. For the EP study, catheters will probably be inserted in your groin and neck. Catheter mapping, or endocardial mapping, is then used to determine the location of the part causing the arrhythmia.
Once the location of the pathway has been determined, the ablation catheter will be inserted at the site. Heat will be administered to the area through radiofrequency waves. These waves will cause scar tissue to form, which prevents the passage of electric impulses.
Destroying the A-V node
Sometimes the atrio-ventricular (A-V) node is the part of the heart that is causing the arrhythmia. The A-V node is situated in the center of the heart, and electrical impulses travel through it to get from the atria to the ventricles. If it is the cause of the arrhythmia, destroying it can prevent the fibrillation from traveling from the atria, where it is not that dangerous, to the ventricles, where it can lead to heart attack. To destroy the A-V node, a small tube is guided to the heart through a vein. Heat, via radiofrequency, is applied to the A-V node to destroy it.
This does not cure the fibrillation; it merely prevents the signals from traveling from the atria to the ventricles. The patient will then have a pacemaker installed to keep the heart from pumping too slowly now that the A-V node is missing. Since the atria are still beating rapidly, there is still a risk of blood clotting and stroke, so the physician will probably prescribe blood-thinning medication.
Last updated: 31-May-04
