Hintringer F, Hartikainen J, Davies D W, Heald S C, Gill J S, Ward D E, Rowland E
St George's Hospital, London, UK.
Circulation. 1995 Dec 15;92(12):3490-6. doi: 10.1161/01.cir.92.12.3490.
Selective radiofrequency (RF) ablation of the slow pathway is an effective treatment for atrioventricular (AV) nodal reentry tachycardia. A previous report showed that rapid junctional tachycardia (JT) caused by RF associated with loss of ventriculoatrial (VA) conduction is related to increased risk for AV block. However, this can be difficult to detect during energy delivery, and more importantly, it cannot be measured before the onset of RF energy delivery. The aim of our study was to determine whether measurements made from electrograms could be used to predict the risk of AV block before RF energy is delivered.
Fifty-eight patients underwent 63 selective slow pathway RF ablation procedures. In 46 (26.9%) of 172 JTs caused by RF, VA block was observed, and in 11 this was followed by AV block of various degrees. Electrograms before each application of RF were analyzed for the interval between the atrial signals in the His bundle catheter and in the distal mapping catheter [A(H)-A(Md)], the interval between the atrial signals in the His bundle catheter and in the proximal coronary sinus catheter [A(H)-A(CS)], the AV ratio, and the presence of a slow pathway potential or a fractionated atrial signal in the distal mapping catheter. Mean cycle length (CL) of JT was calculated if it consisted of at least 10 beats. These parameters were compared between patients with JT who developed VA block and subsequent AV block (group 1), patients with JT and VA block but without subsequent AV block (group 2), and patients with JT without VA block (group 3). The A(H)-A(Md) interval was significantly shorter in group 1 (17 +/- 8 ms) than in groups 2 (33 +/- 8 ms, P < .001) and 3 (32 +/- 10 ms, P < .001), whereas the A(H)-A(Md) intervals of groups 2 and 3 did not differ from each other. CL of JT, A(H)-A(CS) interval, AV ratio, presence of a slow pathway potential, or a fractionated atrial electrogram were not related to the occurrence of AV block.
The A(H)-A(Md) interval provides an electrophysiological marker that can be used in addition to the radiological catheter position to assess the risk for AV block before onset of RF delivery. CL of JT and occurrence of VA block are not related to the risk of AV block.
选择性射频消融慢径路是治疗房室结折返性心动过速的有效方法。先前的一份报告显示，射频消融相关的快速交界性心动过速（JT）伴室房（VA）传导丧失与房室传导阻滞风险增加有关。然而，在能量释放过程中这可能难以检测到，更重要的是，在射频能量释放开始前无法进行测量。我们研究的目的是确定从电图测量结果是否可用于在射频能量释放前预测房室传导阻滞的风险。
58例患者接受了63次选择性慢径路射频消融手术。在由射频引起的172次JT中，46次（26.9%）观察到VA阻滞，其中11次随后出现不同程度的房室传导阻滞。分析每次射频应用前的电图，测量希氏束导管和远端标测导管心房信号之间的间期[A(H)-A(Md)]、希氏束导管和近端冠状窦导管心房信号之间的间期[A(H)-A(CS)]、房室比，以及远端标测导管中是否存在慢径路电位或碎裂心房信号。如果JT至少由10次心搏组成，则计算其平均周期长度（CL）。比较发生VA阻滞及随后房室传导阻滞的JT患者（第1组）、有JT和VA阻滞但无随后房室传导阻滞的患者（第2组）以及有JT但无VA阻滞的患者（第3组）之间的这些参数。第1组的A(H)-A(Md)间期（17±8毫秒）明显短于第2组（33±8毫秒，P<.001）和第3组（32±10毫秒，P<.001），而第2组和第3组的A(H)-A(Md)间期彼此无差异。JT的CL、A(H)-A(CS)间期、房室比、慢径路电位的存在或碎裂心房电图与房室传导阻滞的发生无关。
A(H)-A(Md)间期提供了一种电生理标志物，除了放射学导管位置外，可用于在射频释放开始前评估房室传导阻滞的风险。JT的CL和VA阻滞的发生与房室传导阻滞风险无关。
