Percutaneous Pulmonary Vein Electric Isolation For The Treatment Of Atrial Fibrillation

ObjectivesPulmonary vein isolation ( PVI) has been successfully performed for treatment of paroxysmal atrial fibrillation ( PAF) since being introduced by Hais-saguerre et al. The efficacy and safety were still under accessed due to less cases and experiences. It is know that irrigated ablation catheter can create deeper tissue lesion, the author guess by using irrigated ablation catheter, the success rate will be improved and the complication will be decreased. The incidence of pulmonary vein stenosis has been reported by several authors. However, little is known about the natural history of this problem. In cases where the pulmonary vein stenosis is initially asymptomatic or minor there would be particular concern if the stenosis deteriorated with time. The purpose of this study was to access the efficacy and safety of PVI for treatment of paroxysmal, persistent and permanent atrial fibrillation. This study was also designed to evaluate the efficacy and safety of PVI with saline - irrigated tip ablation catheters and normal 4mm tip catheters for treatment of atrial fibrillation. One more purpose of this study was to observe the pulmonary vein stenosis and remolding after PVI.MethodsThree parts were included in the method of this study; The first part:1. Patients selection; From 2001. 4 to 2002. 7, pulmonary vein isolation procedures were performed for cure of drug resistant atrial fibrillation.2. Electrophysiologic Study and Radiofrec[uency Catheter Ablation:Transesophageal echocardiogram was performed in all patients prior to the electrophysiological study to exclude intracardiac thrombus. Two 8 French Multipurpose Preface sheaths (Biosense Webster, Cordis Corp, CA) were used to access the left atrium transeptally. A circumferential mapping catheter ( LassoTM , Biosense Webster, Diamond Bar, CA) was used for detection and mapping of pulmonary vein potentials ( PVPs). Heparin ( 100U/kg by bolus and 1000 -2000U per hour) was administered after the transeptal punctures. The ostium was defined by contrast venography in right anterior oblique and left anterior oblique projections. The circumferential mapping catheter was advanced sequentially into the pulmonary veins. PVPs were recorded by withdrawing the Lasso catheter to the vein ostium. The ostium was further defined by noting the position at which the ablation and circular mapping catheters fell out of the vein. Coronary sinus pacing was used to enhance delineation of the left sided venous potentials.3. Radiofrequency catheter ablation was performed using a deflectable, 7 French catheter with a 4 mm, standard or irrigated tip electrode ( Blazer, Boston Scientific or Thermocool, Cordis Webster). This catheter has a tip thermistor for temperature controlled current delivery. Ablation was guided by electrical potentials using techniques described by Haissaguerre et al. Ablation positions were as close as possible to the pulmonary vein ostia. We carefully attempted to place each radiofrequency lesion either just outside the vein or within 2 mm of the ostium. The initial power and temperature limits were set at 30W and 50 C. The ablation duration was initially 60 seconds. Rarely the power was increased to 35 W or the duration was increased to 120 seconds when pulmonary vein connections were resistant to ablation at the initial settings. All four pulmonary veins were engaged in all patients and isolation was attempted in all veins where pulmonary potentials were detected. The end point was complete elimination of PVPs.4. Selective Pulmonary Venography and Definition of Pulmonary Vein Stenosis. The pulmonary veins were sequentially and selectively engaged using the long preshaped sheaths. Venography was performed during a hand injection ofradiographic contrast before and after electrical isolation of each vein. Right anterior oblique (30 ) and left anterior oblique (45 ) views were routinely used to acquire digital video runs during the injection. Measurements were made during atrial diastole when sinus rhythm was present. Only venography demonstrating the bifurcation, trunk,...