Sturm M, Hausmann D, Bökenkamp R, Bertram H, Wibbelt G, Paul T
Department of Cardiology and Angiology, Hannover Medical School, Hannover, Germany.
Z Kardiol. 2004 Nov;93(11):884-9. doi: 10.1007/s00392-004-0142-9.
Despite the current clinical use of radiofrequency (RF) catheter ablation in infants and children, the late effects of RF current application at immature myocardium remain unclear. The purpose of this study was to investigate incidence and time course of coronary lesions after RF current application at developing myocardium in an animal model.
In 10 pigs, 6 weeks of age (13+/-2 kg), RF current (500 kHz) was delivered by temperature guidance (75 degrees C) using a steerable electrode catheter (4 mm tip electrode) over 30-second periods. RF lesions were created at the lateral right atrial wall at the tricuspid valve annulus and the lateral left atrial and ventricular wall at the mitral valve annulus. Subsequent coronary angiography and intracoronary ultrasound (ICUS) of the right coronary artery (RCA) and the left circumflex artery (CX) were performed 3, 6, 9 and 12 months after RF current application. Quantitative coronary angiography did not exhibit any significant stenosis of the vessels during the study period. Intimal lesions of the RCA were documented for the first time at the 6-month study in 3 animals by ICUS (mean plaque area 2.2+/-0.2 mm(2), mean area stenosis 30.4+/-4.0%). There was no significant change in lesion length, area stenosis and plaque area at the 9- and 12-month studies. All 3 coronary artery lesions were confirmed in close proximity to myocardial RF lesions by histological examination 12 months after RF delivery. No intimal plaque formation of the CX was observed.
Affection of the RCA as a late sequel after RF current application at the lateral right atrial wall occurred in 3 out of 8 long-term surviving pigs. Three to six months seem to be the time frame for the development of intimal lesions after RF delivery. In this experimental setting, angiography failed to detect these intimal changes. The potential risk of coronary affection may be important for catheter ablation procedures at the right atrial myocardium in infants and small children.
尽管目前射频（RF）导管消融术已应用于婴幼儿临床治疗，但在未成熟心肌上施加RF电流的远期影响仍不明确。本研究旨在探讨在动物模型中，在发育中的心肌上施加RF电流后冠状动脉病变的发生率及时间进程。
对10头6周龄（体重13±2千克）的猪，使用可操控电极导管（尖端电极4毫米），通过温度引导（75摄氏度）在30秒内施加RF电流（500千赫）。在三尖瓣环处的右心房外侧壁以及二尖瓣环处的左心房和心室外侧壁制造RF损伤。在施加RF电流后3、6、9和12个月，对右冠状动脉（RCA）和左旋支动脉（CX）进行后续冠状动脉造影和冠状动脉内超声（ICUS）检查。定量冠状动脉造影显示在研究期间血管未出现任何明显狭窄。在6个月的研究中，首次通过ICUS在3只动物中发现RCA内膜病变（平均斑块面积2.2±0.2平方毫米，平均面积狭窄30.4±4.0%）。在9个月和12个月的研究中，病变长度、面积狭窄和斑块面积均无显著变化。在施加RF电流12个月后，通过组织学检查证实所有3处冠状动脉病变均紧邻心肌RF损伤。未观察到CX内膜斑块形成。
在8头长期存活的猪中，有3头出现了在右心房外侧壁施加RF电流后的远期后遗症——RCA受累。RF电流施加后3至6个月似乎是内膜病变发展的时间范围。在此实验环境下，血管造影未能检测到这些内膜变化。冠状动脉受累的潜在风险对于婴幼儿右心房心肌的导管消融手术可能具有重要意义。
