Circumferential Radiofrequency Ablation of Pulmonary Vein Ostia

Abstract

Background-The pulmonary veins (PVs) and surrounding ostial areas frequently house focal triggers or reentrant circuits critical to the genesis of atrial fibrillation (AF). We developed an anatomic approach aimed at isolating each PV from the left atrium (LA) by circumferential radiofrequency (RF) lesions around their ostia. Methods and Results-We selected 26 patients with resistant AF, either paroxysmal (nϭ14) or permanent (nϭ12). A nonfluoroscopic mapping system was used to generate 3D electroanatomic LA maps and deliver RF energy. Two maps were acquired during coronary sinus and right atrial pacing to validate the lateral and septal PV lesions, respectively. Patients were followed up closely for Ն6 months. Procedures lasted 290Ϯ58 minutes, including 80Ϯ22 minutes for acquisition of all maps, and 118Ϯ16 RF pulses were deployed. Among 14 patients in AF at the beginning of the procedure, 64% had sinus rhythm restoration during ablation. PV isolation was demonstrated in 76% of 104 PVs treated by low peak-to-peak electrogram amplitude (0.08Ϯ0.02 mV) inside the circular line and by disparity in activation times (58Ϯ11 ms) across the lesion. After 9Ϯ3 months, 22 patients (85%) were AF-free, including 62% not taking and 23% taking antiarrhythmic drugs, with no difference (PϭNS) between paroxysmal and permanent AF. No thromboembolic events or PV stenoses were observed by transesophageal echocardiography. Conclusions-Radiofrequency PV isolation with electroanatomic guidance is safe and effective in either paroxysmal or permanent AF.

Cardiac cycle–dependent left atrial dynamics: Implications for catheter ablation of atrial fibrillation

“…Atrial fibrillation (AF) ablation is recommended and is increasingly being adopted as second line therapy in patients with symptomatic AF unresponsive to anti-arrhythmic drugs (1)(2)(3). Manipulation of an ablation catheter in the left atrium (LA) can be time consuming and involve significant fluoroscopy, but new technologies are evolving to facilitate catheter navigation and reduce procedure and fluoroscopy times (4)(5)(6)(7).…”

Differences in atrial fibrillation properties under vagal nerve stimulation versus atrial tachycardia remodeling

“…Ablation of the area with the shortest cycle length (CL) during AF had a profound antiarrhythmic effect in that model. Clinical studies [42][43][44] demonstrated that ablation in PV region and posterior wall, that is areas showing the fastest activity during AF as measured by CL in coronary sinus electrograms, prolonged at first the CL and subsequently terminated the arrhythmia. The areas of shortest CL would correspond to the generators (rotors) responsible for the maintenance of AF.…”

Catheter ablation of atrial fibrillation

“…18 To overcome these limitations, researchers have recently developed a novel catheter ablation approach that involves circumferential lesions created around the ostia of each PV, with the aim of isolating these veins electrically from the left atrium while reducing the risk of PV stenosis. 31,32 This approach eliminates the need for mapping, while it also has the advantage of being able to deal with multiple foci in the PVs, which possibly would not all have been mapped or ablated if the focal ablation approach had been employed.…”

“…Ultrasound energy has been successfully used to create circumferential lesions to isolate the PVs electrically from the atria, 31 while microwave ablation has been carried out to create continuous atrial linear lesions in patients undergoing open heart surgery. 42 The use of lasers is still at an experimental stage, although Nd:YAG lasers have been successfully used in dogs to create atrial linear lesions 43 and circumferential lesions at PV ostia.…”