Chan Rodrigo C, Johnson Susan B, Seward James B, Packer Douglas L
Division of Cardiology, Department of Internal Medicine, Mayo Foundation, Rochester, Minnesota, USA.
Pacing Clin Electrophysiol. 2002 Jan;25(1):4-13. doi: 10.1046/j.1460-9592.2002.00004.x.
Although the determinants of radiofrequency lesion size have been characterized in vitro and in ventricular tissue in situ, the effects of catheter tip length and endocardial surface orientation on lesion generation in atrial tissue have not been studied. Therefore, the dimensions of radiofrequency lesions produced with 4-, 6-, 8-, 10-, and 12-mm distal electrode lengths were characterized in 26 closed-chested dogs. The impact of parallel versus perpendicular catheter tip/endocardial surface orientation, established by biplane fluoroscopy and/or intracardiac echocardiography, on lesion dimensions was also assessed. Radiofrequency voltage was titrated to maintain a steady catheter tip temperature of 75 degrees C for 60 seconds. With a perpendicular catheter tip/tissue orientation, the lesion area increased from 29 +/- 7 mm2 with a 4-mm tip to 42 +/- 12 mm2 with the 10-mm tip, but decreased to 29 +/- 8 mm2 with ablation via a 12-mm tip. With a parallel distal tip/endocardial surface orientation, lesion areas were significantly greater: 54 +/- 22 mm2 with a 4-mm tip, 96 +/- 28 mm2 with a 10-mm tip and 68 +/- 24 mm2 with a 12-mm tip (all P < 0.001 vs perpendicular orientation). Lesion lengths and apparent volumes were larger with parallel, compared to perpendicular tip/tissue orientations, although lesion depth was independent of catheter tip length with both catheter tip/tissue orientations. Electrode edge effects were not observed with any tip length. Direct visualization using intracardiac ultrasound guidance was subjectively helpful in insuring an appropriate catheter tip/tissue interface needed to maximize lesion size. Although atrial lesion size is critically dependent on catheter tip length, it is more influenced by the catheter orientation to the endocardial surface. This information may also be helpful in designing electrode arrays for the creation of continuous linear lesions for the elimination of complex atrial tachyarrhythmias.
尽管已经在体外和心室原位组织中对射频损伤大小的决定因素进行了表征，但尚未研究导管尖端长度和心内膜表面方向对心房组织中损伤产生的影响。因此，在26只开胸犬中对使用4毫米、6毫米、8毫米、10毫米和12毫米远端电极长度产生的射频损伤尺寸进行了表征。还评估了通过双平面荧光透视和/或心内超声心动图确定的平行与垂直导管尖端/心内膜表面方向对损伤尺寸的影响。将射频电压进行滴定，以在60秒内将导管尖端温度维持在75摄氏度。在导管尖端/组织垂直方向下，损伤面积从4毫米尖端时的29±7平方毫米增加到10毫米尖端时的42±12平方毫米，但在通过12毫米尖端进行消融时降至29±8平方毫米。在远端尖端/心内膜表面平行方向下，损伤面积明显更大：4毫米尖端时为54±22平方毫米，10毫米尖端时为96±28平方毫米，12毫米尖端时为68±24平方毫米（与垂直方向相比，所有P<0.001）。与垂直尖端/组织方向相比，平行方向时损伤长度和表观体积更大，尽管在两种尖端/组织方向下损伤深度均与导管尖端长度无关。使用任何尖端长度均未观察到电极边缘效应。在心内超声引导下进行直接可视化在确保获得使损伤尺寸最大化所需的合适导管尖端/组织界面方面具有主观帮助。尽管心房损伤大小严重依赖于导管尖端长度，但它更受导管相对于心内膜表面方向的影响。该信息在设计用于创建连续线性损伤以消除复杂房性快速性心律失常的电极阵列时可能也会有所帮助。
