Willems S, Shenasa H, Kottkamp H, Chen X, Hindricks G, Yli-Mäyry S, Haverkamp W, Wichter T, Rotman B, Breithardt G, Borggrefe M
Hospital of the Westfälische Wilhems University of Münster, Department of Cardiology and Angiology, Germany.
Eur Heart J. 1996 Jul;17(7):1092-102. doi: 10.1093/oxfordjournals.eurheartj.a015006.
Anatomical and electrogram-guided techniques have been used separately for slow pathway ablation in atrioventricular nodal reentrant tachycardia. The aims of the present study were to analyse electrogram characteristics of target sites and biophysical parameters using a combined anatomical and electrogram-guided technique for temperature-controlled radiofrequency catheter ablation of the slow pathway.
Using a temperature-controlled (pre-selected 60 degrees C) catheter system, 53 patients with atrioventricular nodal reentrant tachycardia underwent slow pathway radiofrequency ablation. Mapping was started posteroseptally near the coronary sinus ostium and continued towards the midseptal area if needed. The longest and latest atrial electrograms with an atrioventricular ratio of < or = 0.5 were targeted. After a median of two pulses (mean 2.36 +/- 1.33), atrioventricular nodal reentrant tachycardia was rendered non-inducible in all patients without complications. Successful sites had longer atrial electrograms (78.8 +/- 9.8 vs 67.6 +/- 13.3 ms, P < 0.003) and larger ventricular electrogram amplitudes (92.4 +/- 51.2 vs 63.1 +/- 28.8 mV, P < 0.05) than the failed sites, but had a similar atrioventricular ratio, P-A interval and atrial electrogram amplitude. Overall, an atrial electrogram duration of > or = 70 ms was associated with effective radiofrequency delivery, with 86% sensitivity and 62% specificity. The achieved temperature maximum was 62.3 +/- 9.8 degrees C at successful and 58.8 +/- 9.0 degrees C at unsuccessful sites (ns). There was no significant difference between successful and unsuccessful applications with respect to power output, impedance and total delivery energy. During a pre-discharge study, three patients with inducible atrioventricular nodal reentrant tachycardia underwent a repeat ablation. During 12.3 +/- 2.5 (6-15) months of follow-up, three others had a clinical recurrence of atrioventricular nodal reentrant tachycardia.
The combined approach for slow pathway ablation is highly effective, requiring a low number of radiofrequency pulses. Long atrial activation time seems to be the most powerful predictor of success. Similar catheter tip temperature levels during successful and unsuccessful radiofrequency applications indicate that suboptimal selection of target sites rather than ineffective heating due to poor catheter tissue coupling is responsible for unsuccessful energy delivery.
解剖学及心内电图引导技术已分别用于房室结折返性心动过速的慢径路消融。本研究旨在分析采用解剖学与心内电图联合引导技术进行温控射频导管消融慢径路时靶点的心内电图特征及生物物理参数。
使用温控（预选60℃）导管系统，对53例房室结折返性心动过速患者进行慢径路射频消融。标测从冠状窦口附近的后间隔开始，必要时向中隔区域延续。以房室比≤0.5的最长及最晚心房心内电图为靶点。经中位数为2次脉冲（平均2.36±1.33次）后，所有患者的房室结折返性心动过速均不能被诱发，且无并发症发生。成功靶点的心房心内电图较长（78.8±9.8 vs 67.6±13.3毫秒，P<0.003），心室心内电图振幅较大（92.4±51.2 vs 63.1±28.8毫伏，P<0.05），但房室比、P-A间期及心房心内电图振幅相似。总体而言，心房心内电图持续时间≥70毫秒与有效的射频发放相关，敏感性为86%，特异性为62%。成功靶点处达到的最高温度为62.3±9.8℃，未成功靶点处为58.8±9.0℃（无显著性差异）。成功与未成功消融在功率输出、阻抗及总发放能量方面无显著差异。在放电前研究中，3例可诱发房室结折返性心动过速的患者接受了重复消融。在12.3±2.5（6 - 15）个月的随访期间，另外3例患者出现了房室结折返性心动过速的临床复发。
慢径路消融的联合方法非常有效，所需射频脉冲数量少。较长的心房激动时间似乎是成功的最有力预测因素。成功与未成功射频消融时导管尖端温度水平相似，表明靶点选择欠佳而非导管与组织耦合不良导致加热无效是能量发放未成功的原因。
