A normal heart rhythm is the result of an electrical impulse passing through the heart tissue in one narrow conduction path. Many tachycardias (extremely fast rhythms) are the result of areas of abnormal tissue which cause this electrical system to short circuit. Catheter ablation is based on the idea that by ablating, or destroying, abnormal tissue areas in the heart, its electrical system can be repaired and the heart will return to a normal rhythm.

During catheter ablation, your physician will insert several special long, flexible tubes with wires—called electrode catheters—into your heart. Some of these, called diagnostic catheters, are used to study your abnormal rhythm, or arrhythmia. However, one of these catheters will be used for the actual ablation. Once the doctor determines exactly where abnormal tissue in the heart is located, it can be ablated. Your physician will position the ablation catheter so that it lies on or very close to the abnormal tissue. High-frequency electrical energy is then sent through the ablation catheter into this abnormal tissue. The small area of heart tissue under the tip of the ablation catheter is heated by this high-frequency energy, creating a lesion or tiny scar. As a result, this tissue is no longer capable of conducting or sustaining the arrhythmia.