影像融合系统指导下导管消融心脏外科手术后迟发性右房房性心动过速的初步经验

Initial experience of image integration system guiding catheter ablation for right atrial tachycardia occurring after atriotomy of structural heart disease

目的运用影像融合技术研究心脏外科手术后迟发性右房房性心动过速(AT)的机制并探讨在该技术指导下导管消融该类型AT的有效性。方法从2005年1月到2006年12月在影像融合系统(CartoMerge^(TM) system)指导下对连续40名患者的自发性或诱发的AT进行了完整的电生理标测。消融策略是在影像融合技术指导下在峡部最狭窄处消融,但避开可见的解剖异常处。术后3个月、6个月和每年进行一次临床和24小时动态心电图检查。结果总共发现三种主要的心动过速机制:单折返环大折返AT(MAT,n=36)、双折返环MAT(n=16)以及额外的局灶性AT(n=4)。最常见的关键峡部是三尖瓣峡部(CTI,n=35)和手术切口性峡部(n=36)。部分患者影像融合技术重建后右房可见到明显的瘢痕线、囊样物或瘤样物(n=12),上述解剖异常处都有瘢痕区特有的电生理表现。平均19.5±10.1次消融可阻断峡部。平均随访18±10个月后,80%的患者在不服药的情况下保持窦性心律。8例(20%)患者复发,分别在3～16个月进行了第2次消融;其中2例分别在3个月和5个月后再次复发,前者再次消融成功,后者未再消融。结论影像融合技术不仅能够确定AT的机制,还在精确定位和消融AT的致心律失常基质上具有优势。三维MR/CT影像能够成功重建和配准以用于右房的导管消融,这些真实和详细的解剖学信息有助于对手术导致解剖异常的右房AT进行导管消融。

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 Hoher recordings being performed at three months, six months, and afterwards on a yearly basis. Results Three main tachycardia mechanisms were identified： single-leop 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 integrationsystem 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.