Heart: Supraventricular Tachycardia (SVT)
If other treatments that have been prescribed for your arrhythmia have not provided the relief you need, you doctor may recommend catheter ablation. In catheter ablation, the electrode delivers a low-voltage, high-frequency current that destroys the heart tissue responsible for the arrhythmia.
People who have a catheter ablation can experience:
- A long-term reduction in the number of episodes of arrhythmia and the severity of symptoms, or
- A permanent return to normal heart rhythm
This means that medicines for controlling heart rate or rhythm may be stopped or reduced following successful catheter ablation. Do not modify your medications without consulting your doctor.
The electrophysiologist will discuss any particular risks with you before the procedure.
The procedure always begins with an electrophysiology (EP) study.
Preparing for Catheter Ablation
Your doctor will tell you ahead of time whether to stop taking any of your medications. Do not modify your medications without consulting your doctor.
Usually, your doctor will tell you not to eat or drink for six to eight hours before the test.
The area where the catheter will be inserted will be thoroughly cleaned and shaved. This is usually in the groin, but may be in the neck. You will receive a local anesthetic in that area. The catheters will then be inserted; you may initially feel some pressure at the site of insertion. You will be given a mild sedative.
During Catheter Ablation
The EP and other health-care specialists in the lab will use a variety of imaging and monitoring systems to help them navigate the catheters to your heart, locate the precise location for the ablation, and evaluate their progress.
Also, depending on your anatomy, some specialists will take extra steps to avoid damaging tissue near your esophagus. They may ask you to drink a creamy substance to help the esophagus show up better on the x-ray.
Catheter ablation uses a series of thin, flexible wires (catheters) that are inserted through an artery or a vein (usually in the groin or neck) and guided to the heart. The position of the catheters can be seen using fluoroscopy, a special monitoring technique that uses x-rays. Once in the heart, one or more of the catheters are used to pinpoint the source of the abnormal electrical signals.
Medications will be given to increase your heart rate. You may also be given a drug or electrical stimulation to bring on the abnormal rhythm. This will help the doctor identify the areas of the heart producing the arrhythmia.
Some people may feel some temporary chest discomfort during the procedure. If that happens to you, be sure to tell the doctor, who can give you medication to relieve it.
When the EP has located the source of your arrhythmia, he or she moves another catheter to the site. That catheter delivers bursts of high-energy waves that ablate, or destroy, the abnormal areas. This creates a small scar (called a “lesion”) that electrical signals cannot pass through. After ablating the problem areas, the doctor will try to re-start your arrhythmia to assess the cardiac rhythm. If a fast rhythm does return, further ablation may be needed.
The whole procedure (including the EP study and mapping) may take several hours.