Pulmonary Vein Isolation Using the Visually Guided Laser Balloon: A Prospective, Multicenter, and Randomized Comparison to Standard Radiofrequency Ablation.

BACKGROUND: Balloon catheters have been designed to facilitate pulmonary vein (PV) isolation in patients with paroxysmal atrial fibrillation (AF). The visually guided laser balloon (VGLB) employs laser energy to ablate tissue under direct visual guidance. OBJECTIVES: This study compared the efficacy and safety of VGLB ablation with standard irrigated radiofrequency ablation (RFA) during catheter ablation of AF. METHODS: Patients with drug-refractory paroxysmal AF were enrolled in a multicenter, randomized controlled study of PV isolation using either the VGLB or RFA (control). The primary efficacy endpoint was freedom from protocol-defined treatment failure at 12 months, including symptomatic AF occurring after the 90-day blanking period. The primary efficacy and safety endpoints were powered for noninferiority. RESULTS: A total of 353 patients (178 VGLB, 175 control) were randomized at 19 clinical sites. The mean procedure, ablation, and fluoroscopy times were longer with VGLB compared with controls. The primary efficacy endpoint was met in 61.1% in the VGLB group versus 61.7% in controls (absolute difference -0.6%; lower limit of 95% confidence interval [CI]: -9.3%; p = 0.003 for noninferiority). The primary adverse event rate was 11.8% in the VGLB group versus 14.5% in controls (absolute difference -2.8%; upper limit of 95% CI: 3.5; p = 0.002 for noninferiority), and was mainly driven by cardioversions. Diaphragmatic paralysis was higher (3.5% vs. 0.6%; p = 0.05), but PV stenosis was lower (0.0% vs. 2.9%; p = 0.03) with VGLB. CONCLUSIONS: Despite minimal prior experience, the safety and efficacy of VGLB ablation proved noninferior to RFA for the treatment of paroxysmal AF. (Pivotal Clinical Study of the CardioFocus Endoscopic Ablation System-Adaptive Contact [EAS-AC] [HeartLight] in Patients With Paroxysmal Atrial Fibrillation [PAF] [HeartLight]; NCT01456000).

Pulmonary Vein Isolation Using the Visually Guided Laser Balloon: Results of the U.S. Feasibility Study.

INTRODUCTION: Visually guided laser balloon (VGLB) ablation is unique in that the operator delivers ablative energy under direct visual guidance. In this multicenter study, we sought to determine the feasibility, efficacy, and safety of performing pulmonary vein isolation (PVI) using this VGLB. METHODS: Patients with symptomatic, drug-refractory paroxysmal atrial fibrillation (AF) underwent PVI using the VGLB with the majority of operators conducting their first-ever clinical VGLB cases. The primary effectiveness endpoint was defined as freedom from treatment failure that included: Occurrence of symptomatic AF episodes ≥1 minutes beyond the 90-day blanking, the inability to isolate 1 superior and 2 total PVs, occurrence of left atrial flutter or atrial tachycardia, or left atrial ablation/surgery during follow-up. RESULTS: A total of 86 patients (mean age 56 ± 10 years, 67% male) were treated with the VGLB at 10 US centers. Mean fluoroscopy, ablation, and procedure times were 39.8 ± 24.3 minutes, 205.2 ± 61.7 minutes, and 253.5 ± 71.3 minutes, respectively. Acute PVI was achieved in 314/323 (97.2%) of targeted PVs. Of 84 patients completing follow-up, the primary effectiveness endpoint was achieved in 50 (60%) patients. Freedom from symptomatic or asymptomatic AF was 61%. The primary adverse event rate was 16.3% (8.1% pericarditis, phrenic nerve injury 5.8%, and cardiac tamponade 3.5%). There were no cerebrovascular events, atrioesophageal fistulas, or significant PV stenosis. CONCLUSIONS: This multicenter study of operators in the early stage of the learning curve demonstrates that PVI can be achieved with the VGLB with a reasonable safety profile and an efficacy similar to radiofrequency ablation.

Pulmonary vein isolation using a visually guided laser balloon catheter: the first 200-patient multicenter clinical experience.

BACKGROUND: Because of the technical difficulty with achieving pulmonary vein (PV) isolation in the treatment of patients with paroxysmal atrial fibrillation, novel catheter designs to facilitate the procedure are in development. A visually guided laser ablation (VGLA) catheter was designed to allow the operator to directly visualize target tissue for ablation and then deliver laser energy to perform point-to-point circumferential ablation. Single-center studies have demonstrated favorable safety and efficacy. We sought to determine the multicenter feasibility, efficacy, and safety of performing PV isolation using the VGLA catheter. METHODS AND RESULTS: This study includes the first 200 paroxysmal atrial fibrillation patients treated with the VGLA catheter (33 operators, 15 centers). After transseptal puncture, the VGLA catheter was used to perform PV isolation. Electric isolation was assessed using a circular mapping catheter. Using the VGLA catheter, 98.8% (95% confidence interval, 97.8%-99.5%) of targeted PVs were isolated using a mean of 1.07 catheters per patient. Fluoroscopy and procedure times were 31±21 (mean±SD) and 200±54 minutes, respectively, and improved with operator experience. There were no instances of stroke, transient ischemic attack, atrioesophageal fistulas, or significant PV stenosis. There was a 2% incidence of cardiac tamponade and a 2.5% incidence of phrenic nerve palsy. At 12 months, the drug-free rate of freedom from atrial arrhythmias after 1 or 2 procedures was 60.2% (95% confidence interval, 52.7%-67.4%). CONCLUSIONS: In this multicenter experience of the first 200 patients treated with the VGLA catheter, PV isolation can be achieved in virtually all patients using a single VGLA catheter with an efficacy similar to radiofrequency ablation.

Percutaneous catheter ablation procedures for the treatment of atrial fibrillation.

In light of the significant morbidity and mortality from atrial fibrillation (AF), there has been significant interest in the development of percutaneous catheter ablation procedures for the suppression of AF. Given the success of the surgical Maze procedure, initial catheter-based approaches involved creation of linear atrial lesions. Success rates were low and utility was limited by a high complication rate and long procedural times. The recent discovery that AF is often initiated by atrial ectopic beats has resulted in therapies designed to target the ectopic sources, particularly those within the pulmonary veins. Experience and technological advances have improved the efficacy and safety of such procedures. This article will review catheter ablation procedures for the maintenance of sinus rhythm in patients with AF.

Change in the retrograde atrial activation sequence following radiofrequency modification of the atrioventricular node: implications for the electrophysiologic circuit of a variant of atrioventricular nodal reentrant tachycardia.

INTRODUCTION: Despite the great success in treating AV nodal reentrant tachycardia (AVNRT) with radiofrequency modification of the AV node, the dimensions of the electrophysiologic circuit of this arrhythmia remain unclear, and simple models fail to explain all tachycardia-related phenomena. METHODS AND RESULTS: We describe three unusual cases of supraventricular tachycardia (SVT). In all three cases, retrograde atrial activation during ventricular pacing or during SVT manifested local left atrial electrograms recorded from the coronary sinus preceding the septal atrial electrograms (eccentric activation), with earliest atrial activity at the lateral or posterolateral mitral annulus. Electrophysiologic maneuvers and observations were consistent with AVNRT as the mechanism in each case. In all cases, radiofrequency modification of the AV node eliminated inducible SVT and abolished dual pathway AV nodal physiology. The retrograde atrial activation sequence during ventricular pacing changed after ablation in each case, with septal atrial electrograms preceding left atrial electrograms recorded from the coronary sinus (concentric activation). CONCLUSION: The observations in these cases cannot be explained by the traditional model of slow, fast, and intermediate AV nodal pathways. A model incorporating a circuit close to the AV node with left atrial and coronary sinus connections is proposed.