Woo E J, Tungjitkusolmun S, Cao H, Tsai J Z, Webster J G, Vorperian V R, Will J A
School of Electronics and Information, Kyung Hee University, Yongin, Kyongki-do, Korea.
IEEE Trans Biomed Eng. 2000 Jan;47(1):23-31. doi: 10.1109/10.817616.
Radio-frequency (RF) cardiac ablation has been very successful for treating arrhythmias related with atrioventricular junction and accessory pathways with successful cure rates of more than 90%. Even though ventricular tachycardia (VT) is a more serious problem, it is known to be rather difficult to cure VT using RF ablation. In order to apply RF ablation to VT, we usually need to create a deeper and wider lesion. Conventional RF ablation electrodes often fail to produce such a lesion. We propose a catheter-electrode design including one or more needle electrodes with a diameter of 0.5-1.0 mm and length of 2.0-10 mm to create a lesion large enough to treat VT. One temperature sensor could be placed at the middle of the needle electrode for temperature-controlled RF ablation. From finite element analyses and in vitro experiments, we found that the depth of a lesion is 1-2 mm deeper than the insertion depth of the needle and the width increases as we increase the diameter of the needle and the time duration. We showed that a single needle electrode can produce a lesion with about 10-mm width and any required depth. If a wider lesion is required, more than one needle with suggested structures can be used. Or, repeated RF ablations around a certain area using one needle could produce a cluster of lesions. In some cases, a catheter with both conventional electrode and needle electrode at its tip may be beneficial to take advantage of both types of electrode.
射频（RF）心脏消融术在治疗与房室交界和旁路相关的心律失常方面非常成功，治愈率超过90%。尽管室性心动过速（VT）是一个更严重的问题，但已知使用射频消融术治疗VT相当困难。为了将射频消融术应用于VT，我们通常需要制造更深、更宽的损伤。传统的射频消融电极往往无法产生这样的损伤。我们提出一种导管电极设计，包括一个或多个直径为0.5 - 1.0毫米、长度为2.0 - 10毫米的针状电极，以制造出足以治疗VT的大损伤。可以在针状电极的中间放置一个温度传感器，用于温度控制的射频消融。通过有限元分析和体外实验，我们发现损伤深度比针状电极的插入深度深1 - 2毫米，并且随着针状电极直径和持续时间的增加，损伤宽度会增大。我们表明，单个针状电极可以产生宽度约为10毫米、任意所需深度的损伤。如果需要更宽的损伤，可以使用多个具有建议结构的针状电极。或者，使用一根针状电极在特定区域周围重复进行射频消融可以产生一系列损伤。在某些情况下，尖端同时具有传统电极和针状电极的导管可能有利于利用这两种类型的电极。
