ABSTRACT
Objective To investigate the mechanisms of right atrial tachycardia(AT) occurring after atriotomy of structural heart disease under the guidance of image integration system(CartoMerge system) and explore the efficacy of catheter ablation by using the aboved technique.Methods From January 2005 to December 2006,forty consecutive drug-refractory patients presenting with AT underwent complete electroanatomic mapping of spontaneously occurring and inducible right ATs.The ablation strategy was to avoid visible anatomic anomaly under the guidance of image integration system and to transect the isthmus,usually targeting the narrowest portion of the isthmus.Patients were followed up on an outpatient basis with clinical evaluation and 24-hour Holter recordings being performed at three months,six months,and afterwards on a yearly basis.Results Three main tachycardia mechanisms were identified: single-loop macroreentrant atrial tachycardia(MAT)(n=36),double-loop MAT(n=16),and focal AT(n=4).In most MATs,critical isthmus areas were identified most frequently the cavotricuspid isthmus(CTI)(n=35) and the surgical incision isthmus(n=36).Surgical incision causing obvious morphological anomalies including scar-like anomaly,pouch-like anomaly,and node-like anomaly could be visible by image integration technique in 12 patients,which had the electrophysiological characteristics of a surgical incision(a CDP or scar).A mean number of 19.5?10.1 radiofrequency(RF) applications were delivered to terminate the circuit.During a follow-up of 18?10 months the RF ablation was acutely successful in all patients.Eight patients(20%) had an early recurrence of MAT and needed an additional ablation procedure.Conclusion Image integration system not only allows reconstruction of AT mechanisms,but also represents an advance in the accurate localization and ablation of the arrhythmogenic substrate of postsurgical AT.Three-dimensional MR/CT images of RA can be successfully extracted and registered to anatomically guide catheter ablation in RA.The display of real and detailed anatomic information during the procedure enables tailored RF ablation to individual distorted anatomy related with surgical incision.
ABSTRACT
Objective To study the effect of circumferential pulmonary vein isolation(CPVI) guided by Carto-Merge and Lasso catheter for the treatment of atrial fibrillation(AF).Methods Fifty-six drug refractory patients(41 male) with paroxysmal AF were enrolled into this study with a mean age of(58.5?12.7) years.Ostia of pulmonary veins(PVs) were identified by Carto-Merge.Then circumferential pulmonary vein isolation was performed.The endpoint of ablation was abolishment or dissociation of the pulmonary vein potentials(PVPs).Results Mean distance between electroanatomic mapping points and MRI surfaces was(1.79?0.33) mm as a whole in this group.Abolishment or dissociation of PVPs was accomplished in 52 patients(92.9%) during the first procedure.After a mean(18.3?5.7) months of follow up,41 patients(73.2%) maintained sinus rhythm.Ten patients received a second ablation procedure,and 8 were free of atrial tachyarrhythmias after a mean(8.2?6.9) months of the second follow up.No PV stenosis was identified after ablation procedure.Conclusion Combination of Lasso catheters with Carto-Merge to guide the CPVI procedure can confirm the isolation of PVs and lower the incidence of PVs stenosis.
ABSTRACT
Objective To explore the mechanism of macro-reentry atrial tachycardia and to guide catheter ablation using electroanatomic mapping system in 3 patients.Methods Three patients(two females),aged 51?12 years,with atrial tachycardia were included.The mean history of symptom was 19?11 years.Conventional electrophysiological study was performed to determine the location of atrial tachycardia before the three dimensional geometry reconstruction.After voltage and activation maps were constructed,the mechanism of tachycardia was analyzed and the slow conduction areas(critical isthmus) were verified.Radiofrequency energy was delivered using irrigated-tip catheter.Results Though there was no evidence to suggest structural heart diseases,scar areas were found in the mapped atria in all the three cases.The mechanism of atrial tachycardia was found to be counter-clockwise macro-reentry around tricuspid valve,counter-clockwise macro-reentry around superior vena cava,and figure "8" reentry in left atria in the 3 patients respectively.The respective critical isthmus was found to be between the lateral scar and tricuspid valve,the lateral scar and superior vena cava,and two scars on the left atria roof.Ablation in the critical isthmus terminated all tachycardia.There were no atrial tachycardia recurrence during a follow-up of 9-10 months.Conclusion The substrate and electrophysiological mechanism of macro-reentry atrial tachycardia could be identified clearly,and navigation ablation could be performed effectively under the guidence of electroanatomic mapping.