Laohaprasitiporn D, Walsh E P, Saul J P, Triedman J K
Department of Cardiology, Children's Hospital, Boston, MA 02115, USA.
Pacing Clin Electrophysiol. 1997 May;20(5 Pt 1):1283-91. doi: 10.1111/j.1540-8159.1997.tb06781.x.
Transient interruption of accessory pathway (AP) conduction is often encountered during creation of RF lesions, with return of conduction after seconds to weeks. Maximum catheter tip temperature (Tmax) has not been shown to be a good predictor of successful RF ablation. However, other indices related to catheter tip temperature (T) may predict permanent AP interruption. Ninety-one successful RF applications in 58 patients (mean age 11.9 +/- 5.5 years, 38 WPW syndrome, 18 concealed AP, 2 both) were reviewed retrospectively. Forty-two RF applications were transiently successful, with a median time of AP conduction recurrence of 120 seconds (sec; range, 1 sec to > 1 day). This group was compared with 49 permanently successful RF applications. T was measured and controlled using the Medtronic Atakr system (San Jose, CA, USA). RF lesion duration, power output, Tmax and time to Tmax (tmax) were not significantly different between the two groups. By univariate analysis, each of the following indices was able to discriminate between the transient and permanent lesions, and highly correlated with one another, T at the moment of AP interruption (Tsucc; transient 55.0 +/- 7.9 degrees C vs permanent 49.8 +/- 7.7 degrees C, P = 0.0025), time to success (tsucc; transient 4.0 +/- 3.0 sec vs permanent 1.8 +/- 1.3 sec, P = 0.0001), ratio of Tsucc/Tmax (transient 0.76 +/- 0.23 vs permanent 0.57 +/- 0.27, P = 0.0007) and ratio of tsucc/tmax (transient 0.91 +/- 0.69 vs permanent 0.41 +/- 0.41, P = 0.0001). By logistic regression analysis, no single variable or combination of variables was superior to tsucc for prediction of outcome, with a breakpoint of 2.3 seconds having a sensitivity of 74% and a specificity of 65%. During temperature controlled RF application, indices of time and temperature were well-correlated with permanent elimination of AP conduction. Time to interruption of AP conduction < 2.3 seconds after the onset of RF application was predictive of the permanence of successful RF applications. Known relations between RF lesion volume and catheter tip temperature suggest that early conduction block may be an indicator of anatomical proximity of the catheter tip and the AP. These data suggest that, in conjunction with electrogram criteria, selection criteria for optimal sites for RF, application may continue to be refined after the onset of RF application, and support the practice of terminating RF application if AP conduction is not rapidly interrupted.
在射频消融病灶形成过程中，常常会出现附加旁道（AP）传导的短暂中断，数秒至数周后传导恢复。最高导管尖端温度（Tmax）尚未被证明是射频消融成功的良好预测指标。然而，与导管尖端温度（T）相关的其他指标可能预测AP传导的永久性中断。回顾性分析了58例患者（平均年龄11.9±5.5岁，38例预激综合征，18例隐匿性AP，2例两者兼具）的91次成功射频消融应用。42次射频消融应用短暂成功，AP传导复发的中位时间为120秒（范围，1秒至>1天）。将该组与49次永久性成功的射频消融应用进行比较。使用美敦力Atakr系统（美国加利福尼亚州圣何塞）测量和控制T。两组之间的射频消融持续时间、功率输出、Tmax和达到Tmax的时间（tmax）无显著差异。通过单因素分析，以下每个指标都能够区分短暂性和永久性病灶，且彼此高度相关，AP中断时的T（Tsucc；短暂性为55.0±7.9℃，永久性为49.8±7.7℃，P = 0.0025）、达到成功的时间（tsucc；短暂性为4.0±3.0秒，永久性为1.8±1.3秒，P = 0.0001）、Tsucc/Tmax的比值（短暂性为0.76±0.23，永久性为0.57±0.27，P = 0.0007）以及tsucc/tmax的比值（短暂性为0.91±0.69，永久性为0.41±0.41，P = 0.0001）。通过逻辑回归分析，没有单一变量或变量组合在预测结果方面优于tsucc，断点为2.3秒时，敏感性为74%，特异性为65%。在温度控制的射频消融应用过程中，时间和温度指标与AP传导的永久性消除密切相关。射频消融开始后<2.3秒出现AP传导中断可预测成功射频消融应用的永久性。射频消融病灶体积与导管尖端温度之间的已知关系表明，早期传导阻滞可能是导管尖端与AP解剖学接近程度的一个指标。这些数据表明，结合心电图标准，射频消融应用最佳部位的选择标准在射频消融开始后可能需要不断完善，并支持在AP传导未迅速中断时终止射频消融应用的做法。
