Until the late 1980s or early 1990s, the only practical treatment option for most abnormal tachycardias was medication. While it is true that rare patients with severe and medically refractory forms of tachycardia were treated with open-heart surgery or high energy direct current internal ablations, for the vast majority of patients with cardiac arrhyhtmias medication was the only realistic choice. Radiofrequency (RF) catheter ablation is an invasive procedure developed in 1990 that, unlike trteatment using medication, offers the opportunity to cure many types of cardiac arrhythmias. The following tachyarrhythmias may be amenable to cure using RF catheter ablation:

• AV nodal reentrant tachycardia
• AV reciprocating tachycardia (WPW syndrome)
• Many, but not all, forms of atrial tachycardia and atrial flutter
• Selected patients with paroxysmal atrial fibrillation
• Some varieties of atypical ventricular tachycardia
  

The success rate for cure varies. In general, AV nodal reentrant tachycardia and AV reciprocating tachycardia have the highest success rates, although some forms of atrial flutter, atrial tachycardia, and atypical ventricular tachycardia may also have high cure rates.

The principle behind catheter ablation is simple. Elimination of an arrhythmia can be achieved by destroying a small, but critical, patch of heart tissue responsible for causing the arrhythmia. Controlled destruction of the target cardiac tissue is accomplished using radiofrequency energy. RF energy is similar to microwave energy or electrocautery used during surgery. Just as microwave energy can heat food in a microwave oven, precisely directed RF energy delivered through the small tip of a temporary intracardiac electrode catheter can “heat-up” and destroy a tiny patch of cardiac tissue critical to the initiation or maintenance of a tachyarrhythmia. The thee factors that tend to limit the success of the RF catheter ablation technique are 1) inability to localize (or "map") the arrhythmia, 2) inability to position the tip of the catheter at the critical target site of the arrhythmia and, 3) inability to deliver adequate RF energy and heating at the critical target site.

Catheter ablation is performed in a special procedure room called an electrophysiology (EP) laboratory. To perform a catheter ablation procedure temporary electrode catheters must be placed inside the heart through veins and arteries, 2) a diagnostic analysis (an EP study) is then performed to define the mechanism of the arrhythmia and localize the critical target tissue that must be destroyed and, 3) perform the actual ablation procedure during which the tip of the ablation catheter is positioned at the critical target tissue and adequate RF energy is delivered to destroy the critical patch of tissue (Figure 1 below).

Figure 1. Schematic diagram illustrating the principles befind RF catheter ablation of AV nodal reentrant tachycardia (AVNRT) (panel A) and AV reciprocating tachycardia (AVRT) (panel B). In the case of AVNRT, ablation is directed at the extra pathway (the "slow pathway") in the AV node. In the case of AVRT, ablation is directed at the extra connection (the "accessory connection") located outside the AV node but connecting the upper and lower heart chambers.