Catheter Ablation of Paroxysmal Supraventricular Tachycardia

Radiofrequency (RF) catheter ablation became first-line therapy for supraventricular tachycardia in patients with Wolff-Parkinson-White syndrome1–5 and atrioventricular (AV) nodal reentrant tachycardia (AVNRT)6–11 in the early 1990s. High ablation success (>90%) and low complication rates (<5%) were found by numerous investigators.1–11 This article describes these ablation techniques with a focus on approaches to ablation of the forms of accessory AV pathways and AVNRT that are difficult to ablate, as well as the less common variants. Between 1989 and 2005, we performed catheter ablation at the University of Oklahoma Health Sciences Center in 1702 patients with 1728 accessory pathways. Acute ablation success was achieved in 1707 (98.8%) of the 1728 accessory pathways. At the 1-year follow-up, conduction (ventricular preexcitation and/or tachycardia) recurred in 92 (5.4%) of the 1707 accessory pathways that had achieved acute success. The recurrence rate was highest for anteroseptal accessory pathways (17 of 116, 14.7%), intermediate for posteroseptal accessory pathways (48 of 476, 10.1%), and lowest for left and right free-wall accessory pathways (17 of 756, 2.2%; and 10 of 359, 2.8%, respectively). Successful repeat ablation was achieved in 71 of the 92 accessory pathways, for a 1-year success of 1686 (97.6%) of the total 1728 accessory pathways. Of the 1702 patients, 904 (53%) had undergone 1 to 4 prior failed catheter and/or surgical ablation procedures at other institutions. From our experience in these 904 patients, we classify the causes for accessory pathway ablation failure into 3 groups: accessory pathway localization error (60%); unusual and unsuspected accessory pathway location (5%); and technical difficulties, including locations that are difficult to access with the ablation catheter, ablation at sites of low blood flow (limiting RF power), and ablation at sites associated with a high risk of injury to a coronary artery or the AV node (35%). ### Causes of Accessory Pathway Ablation Failure #### Mapping/Localization Error The most …