Safety of pulmonary vein isolation and left atrial complex fractionated atrial electrograms ablation for atrial fibrillation with phased radiofrequency energy and multi-electrode catheters.

AIMS: Recently, a multi-electrode catheter system using phased radiofrequency (RF) energy was developed specifically for atrial fibrillation (AF) ablation: the pulmonary vein ablation catheter (PVAC), the multi-array septal catheter (MASC), and the multi-array ablation catheter (MAAC). Initial results of small trials have been promising: shorter procedure times and low adverse event rates. In a large single-centre registry, we evaluated the adverse events associated with multi-electrode ablation catheter procedures with PVAC alone, or combined with MASC and MAAC. METHODS AND RESULTS: In all, 634 consecutive patients with AF had 663 procedures with multi-electrode ablation catheters, 502 patients with the PVAC alone, 128 patients with PVAC/MASC/MAAC, 29 redo procedures with the PVAC or PVAC/MASC/MAAC, and 4 patients had a complicated transseptal puncture. Major and minor adverse events during 6 month follow-up were registered. In 15 cases (2.3%), major adverse events were seen within the first month after the procedure. These included complicated transseptal puncture (4), stroke (2), transient ischaemic attack (5), acute coronary syndrome (2), femoral pseudoaneurysm (1), and arteriovenous fistulae (1). Minor adverse events were seen in 10.7% at 6 months, mostly due to femoral haematoma (3.9%), and non-significant PV stenosis (5.2%). There was no difference in the occurrence of major adverse events between PVAC alone, or PVAC/MASC/MAAC ablation. CONCLUSION: Ablation with phased RF and multi-electrode catheters is accompanied by a major adverse event rate of 2.3% within 1 month and a minor event rate of 10.7% at 6 months.

No severe pulmonary vein stenosis after extensive encircling pulmonary vein isolation: 12-month follow-up with 3D computed tomography.

Few studies have explored the utility of local electrogram-guided extensive encircling pulmonary vein isolation (EEPVI) by analyzing the pulmonary vein (PV) anatomy and occurrence of stenosis using multidetector computed tomography (MDCT). One hundred seventy-six paroxysmal atrial fibrillation (AF) patients underwent EEPVI with a double lasso technique. MDCT was performed in all patients before and at 3, 6 and 12 months after the ablation procedures to screen for PV stenosis. PV stenosis was defined as a >30% reduction in its diameter. A total of 700 PVs were analyzed. PV stenosis was observed in 15 of 700 PVs (2.1%). All stenoses were mild (mean 34.5 ± 3.3%). They were all asymptomatic, and none required treatment. After 12 months of follow-up, the PV narrowing regressed significantly compared with that at 3 months in the patients with PV stenosis (34.5 ± 3 to 30.4 ± 5%, P < 0.05). The remaining PVs exhibited a stable anatomy, and there was no significant progression of the PV narrowing. The results of this study demonstrated that detectable PV stenosis occurred in 2.1% of the PVs, and all stenoses were mild. Moreover, a significant regression of the PV narrowing was observed after 12-months of follow-up. This indicates that the local electrocardiogram-guided EEPVI was relatively safe regarding severe PV stenosis.

Evolving anatomic and electrophysiologic considerations associated with Fontan conversion.

The principles of Fontan conversion with arrhythmia surgery are to restore the cardiac anatomy by converting the original atriopulmonary connection to a total cavopulmonary artery extracardiac connection and treat the underlying atrial arrhythmias. Successful outcomes of this procedure are dependent on a thorough understanding of several factors: the patient's fundamental diagnosis of single-ventricle anatomy, the resultant cardiac configuration from the original atriopulmonary Fontan connection, right atrial dilatation that leads to atrial flutter or fibrillation, and associated congenital cardiac anomalies. The purpose of this article is to present some of the more challenging anatomic and electrophysiologic problems we have encountered with Fontan conversion and arrhythmia surgery and the innovative solutions we have used to treat them. The cases reviewed herein include: takedown of a Bjork-Fontan modification, right ventricular hypertension and tricuspid regurgitation after atriopulmonary Fontan for pulmonary atresia and intact ventricular septum, takedown of atrioventricular valve isolation patch for right-sided maze procedure, resultant hemodynamic considerations leading to intraoperative pulmonary vein stenosis after Fontan conversion, unwanted inferior vena cava retraction during the extracardiac connection, right atrial cannulation in the presence of a right atrial clot, distended left superior vena cava causing left pulmonary vein stenosis, dropped atrial septum, and the modified right-sided maze procedure for various single-ventricle pathology. Since 1994 we have performed Fontan conversion with arrhythmia surgery on 109 patients with a 0.9% mortality rate. We attribute our program's success in no small measure to the strong collaborative efforts of the cardiothoracic surgery and cardiology teams.

Detection of inadvertent catheter movement into a pulmonary vein during radiofrequency catheter ablation by real-time impedance monitoring.

INTRODUCTION: During radiofrequency ablation to encircle or isolate the pulmonary veins (PVs), applications of radiofrequency energy within a PV may result in stenosis. The aim of this study was to determine whether monitoring of real-time impedance facilitates detection of inadvertent catheter movement into a PV. METHODS AND RESULTS: In 30 consecutive patients (mean age 53 +/- 11 years) who underwent a left atrial ablation procedure, the three-dimensional geometry of the left atrium, the PVs, and their ostia were reconstructed using an electroanatomic mapping system. The PV ostia were identified based on venography, changes in electrogram morphology, and manual and fluoroscopic feedback as the catheter was withdrawn from the PV into the left atrium. Real-time impedance was measured at the ostium, inside the PV at approximately 1 and 3 cm from the ostium, in the left atrial appendage, and at the posterior left atrial wall. There was an impedance gradient from the distal PV (127 +/- 30 Omega) to the proximal PV (108 +/- 15 Omega) to the ostium (98 +/- 11 Omega) in each PV (P < 0.01). There was no significant impedance difference between the ostial and left atrial sites. During applications of radiofrequency energy, movement of the ablation catheter into a PV was accurately detected in 80% of the cases (20) when there was an abrupt increase of >/=4 Omega in real-time impedance. CONCLUSION: There is a significant impedance gradient from the distal PV to the left atrium. Continuous monitoring of the real-time impedance facilitates detection of inadvertent catheter movement into a PV during applications of radiofrequency energy.

Circular mapping and ablation of the pulmonary vein for treatment of atrial fibrillation: impact of different catheter technologies.

OBJECTIVES: We conducted this study to compare the efficacy and safety of different catheter ablation technologies and of distal versus ostial pulmonary veins (PV) isolation using the circular mapping technique. BACKGROUND: Electrical isolation of the PVs in patients with atrial fibrillation (AF) remains a technical challenge. METHODS: Two hundred eleven patients (163 men; mean age 53 +/- 11 years) with symptomatic AF were included in this study. In the first 21 patients (group 1), distal isolation (> or = 5 mm from the ostium) was achieved targeting veins triggering AF. In the remaining 190 patients (group 2), ostial isolation of all PVs was performed using 4-mm tip (47 patients), 8-mm tip (21 patients), or cooled-tip (122 patients) ablation catheters. RESULTS: Distal isolation was able to eliminate premature atrial contractions (PACs) and AF in six of 21 patients (29%) and 10 of 34 PVs. After a mean follow-up time of 6 +/- 4 months, no patients treated with the 8-mm tip catheter experienced recurrence of AF, whereas 21% (10 of 47 patients) and 15% (18 of 122 patients) of the patients ablated with the 4-mm tip and the cooled-tip ablation catheters experienced recurrence of AF after a mean follow-up of 10 +/- 3 and 4 +/- 2 months, respectively. Significant complications including stroke, tamponade, and severe stenosis occurred in 3.5% (8/211) of patients. CONCLUSIONS: Catheter technologies designed to achieve better lesion size appeared to have a positive impact on procedure time, fluoroscopy time, number of lesions, and overall efficacy. Although distal isolation can be achieved with fewer lesions, ostial isolation is required in the majority of patients to eliminate arrhythmogenic PACs and AF.