三尖瓣环传导时间在确定典型心房扑动消融终点中的价值

Determination of ablative end-point for typical atrial flutter by tricuspid valve annulus conductional time

目的 评价三尖瓣环的传导时间在确定心房扑动（房扑）消融终点中的价值.方法 19例经体表心电图证实为典型房扑的患者,在心动过速中根据房扑激动顺序及拖带标测证明折返环沿三尖瓣环运行.测定房扑周长（tachycardial interval,TCL）及起搏后间期（post-pacing interval,PPI）.在三尖瓣环与下腔静脉之间的峡部消融,经冠状窦口及低位右心房起搏证明峡部双向阻滞.分别在冠状窦口、冠状窦远端及高位右心房刺激,用大头电极在峡部消融线上记录在3个部位起搏时的双电位间期（double potential interval,DPI）,DPI=刺激信号至第二个电位间期（T2）-刺激信号至第一个电位间期（T1）;三尖瓣环传导时间（tricuspid valve annulus conduction time,TACT）,TACT=（T1＋T2）-（PPI-TCL）;计算TACT/TCL.结果 19例患者在消融术中均形成峡部双向阻滞,无并发症发生,停用任何抗心律失常药物,平均随访（27±8）个月,复发1例,经再消融后成功.TCL为210～385 ms（平均267.21±36.64 ms）,冠状窦近端测得的PPI为235～390 ms（平均291.32±42.88 ms）, 冠状窦远端PPI为273～450 ms（平均334.25±43.04 ms）,高位右心房的PPI为230～385 ms（平均277.13±35.91 ms）.提示高位右心房及冠状窦口接近折返环（与TCL相比,P＞0.05）,而冠状窦远端远离折返环（与TCL相比,P＜0.05）.经冠状窦口及低位右心房起搏证实峡部双向阻滞后,分别于冠状窦口、冠状窦远端及高位右心房起搏测定DPI,分别为（152.56±56.66） ms,（150.08±48.35） ms及（85.6±34.47） ms.高位右心房起搏时DPI与冠状窦起搏时比较差异有统计学意义（P＜0.05）.3个部位计算的TACT分别为（234.72±58.03） ms、（219.73±40.87） ms,（232.3±43.24） ms,差异无统计学意义.三个部位计算的TACT/TCL分别为（0.87±0.14）,（0.82±0.12）及（0.91±0.15）,差异无统计学意义.结论 三尖瓣环传导时间不受起搏部位的影响,仅与环内折返运动时间长短有关.不论房扑周长的长短及双电位间期的大小,只要三尖瓣环传导时间与房扑周长之比接近于1,提示峡部完全阻滞.

Objective To verify the role of tricuspid valve anntdus eonduetional time in determination of the ablative end-point. Methods Nineteen patients with typical flutter demonstrated by EKG and intracardiac electrophysiological exam were enrolled in the study. Tachycardial interval （TCL） and post-pacing interval （PPI） were measured during tachycardia. The double potential interval （DPI） was defined as the second component （T2） minus the first component of double potential （T1）, tricuspid valve anntdus conduction time （TACT） was defined as （T1 ＋T2） - （PPI - TCL）. Results Complete isthmus conduction block was achieved demonstrated by the change of active sequence during different sites pacing in all the 19 patients. Atrial flutter reoccurred in 1 patient during follow-up. TCL ranged from 210 ms to 385 ms （267.21 ± 36.64 ms）. PPI ranged from 235 ms to 390 ms measured during proximal coronary sinus pacing （291.32± 42.88 ms）, ranged from 273 ms to 450 ms measured during distal coronary sinus pacing （334.25 ± 43.04 ms）, and ranged from 230 ms to 385 ms measured during high right atrial pacing （277.13 ± 35.91 ms）. It indicated that the high right atrial and the proximal coronary sinus located on the reenlrant loop （compared with TCL, P 〉 0.05） but the distal coronary sinus was out of the reentrant loop （compared with TCL, P〈0.05）. DPI were 152.56±56.66 ms, 150.08±48.35 ms and 85.6±34.47 ms during pacing from the proximal coronary sinus, distal coronary sinus and the high right atrial respectively. DPI shortened remarkably during pacing from the high right atrial （ P 〈 0.05 ）. TACT were 234.72 ± 58.03 ms, 219.73 ± 40.87 ms and 232.3 ± 43.24 ms during pacing from the proximal coronary sinus distal coronary sinus and the high right atrial respectively. The TACT/TCL ratio were 0.87 ± 0.14, 0.82 ± 0.12 and 0.91 ± 0.15 during pacing from the proximal coronary sinus, distal coronary sinus and the high right atrial respectively. Conclusion TACT remains stable during different sites pacing. TACT/TCL approaching to 1 indicates complete isthmus block.