Ablation is a procedure to destroy very small, carefully selected parts of the heart that are causing tachycardia – an abnormally fast heartbeat. Ablation enables the heart to beat more slowly and normally again. Catheter ablation has become the preferred technique for treating tachycardia. It has replaced direct-current shock ablation, and is more frequently taking the place of some open-heart surgeries and long-term use of antiarrhythmic medications. Although there are several forms of catheter ablation, the two most common are radiofrequency ablation and cryoablation.

Radiofrequency ablation uses radio energy to heat and destroy the defective tissues. It is by far the most common form of ablation.

Cryoablation uses intense cold to freeze and destroy the tissues. As with radiofrequency ablation, cryoablation involves insertion of a catheter through a blood vessel and up to the heart. However, rather than delivering radiofrequency energy, a highly specialized catheter produces extreme cold in the area. This causes tiny ice crystals in and around the abnormal cells, destroying those cells.

Ablation may be used to treat any of the following conditions:

• AV nodal reentrant tachycardia. A condition in which the heart's electrical system “short circuits” due to an extra pathway in, or adjacent to, the AV node.
  
  
• Wolff-Parkinson-White syndrome. A condition in which the normal electrical signals in the heart travel along an extra, abnormal electrical pathway. This can cause an abnormal heart rhythm (arrhythmia). The condition is believed to be present from birth (a congenital heart defect). In certain cases, physicians might recommend ablation for young adults who have Wolff-Parkinson-White, but do not experience symptoms. Ablation has been shown to lower the risk of developing serious heart-rhythm abnormalities later in life.
  
  
• AV junctional tachycardia. Abnormally fast heart rhythms that result from electrical impulses originating in the AV junction, the area of the heart that includes the AV node, the area just above the AV node, and the area just below the AV node.
  
  
• Atrial fibrillation. The extremely rapid and uncoordinated contraction of the upper chambers of the heart (atria).
  
  
• Atrial flutter. A condition similar to atrial fibrillation except that the rapid firing of impulses occurs in a regular pattern, rather than uncoordinated.
  
  
• Atrial tachycardia. Abnormally fast heart rhythms that result from electrical impulses originating in one of the two upper chambers of the heart (atrium).
  
  
• Ventricular tachycardia. Abnormally fast heart rhythms that result from electrical impulses originating in one of the two lower chambers of the heart (ventricle).
  
  
• Ventricular fibrillation. Recent data suggests that VF, in certain patients, may be initiated by a trigger that can be identified and ablated. However, this procedure is used as a preventive measure. Once ventricular fibrillation has begun, it is an extremely dangerous condition that requires immediate intervention to prevent sudden cardiac death.

A third type of ablation, alcohol septal ablation, is used in some cases to treat hypertrophic cardiomyopathy, or abnormal enlargement of the heart muscle that constricts blood flow. During this procedure, the physician uses injections of alcohol (ethanol) to cause a “planned heart attack” in the septum, or wall of muscle that separates the right and left sides of the heart.

Patients with atrial fibrillation or ventricular tachycardia may need to continue antiarrhythmic therapy after ablation. Patients undergoing ablation of the AV node typically require a pacemaker. Also, some patients, especially those who are at higher risk of ventricular arrhythmias, may be required to have an implantable cardioverter defibrillator (ICD). These devices monitor the heart rhythm and interrupt dangerous and severe ventricular arrhythmias with a strong electrical shock. They can be combined with pacemakers.