Nath S, Redick J A, Whayne J G, Haines D E
Department of Medicine, University of Virginia Health Sciences Center, Charlottesville 22908.
J Cardiovasc Electrophysiol. 1994 Oct;5(10):838-45. doi: 10.1111/j.1540-8167.1994.tb01122.x.
We hypothesized that myocardial injury following radiofrequency (RF) catheter ablation may extend beyond the region of acute coagulation necrosis as defined by histochemical staining.
Five RF lesions were created in vivo in the left ventricle of two dogs using a 4-mm tipped ablation electrode in which RF power was adjusted to maintain an electrode-tissue interface temperature of 85 degrees C for 60 seconds. The lesions were bisected; one half of the lesions were stained with nitroblue tetrazolium (NBT) and the other half processed for electron microscopy. Three zones of interest were identified extending 0-3 mm, 3-6 mm, and > 6 mm from the visible pathologic lesion border. The degree of ultrastructural injury to the myocardium was scored for each zone. Electron microscopy demonstrated the presence of significant abnormalities of the plasma membrane, mitochondria, sarcomeres, sarcoplasmic reticulum, and gap junctions of myocytes, as well as damage to the microvasculature extending up to 6 mm beyond the pathologic lesion edge. The plasma membrane and gap junctions of myocytes and the microvasculature appeared particularly sensitive to thermal injury, whereas the intercalated discs were relatively thermally resistant.
RF catheter ablation results in ultrastructural damage to the myocardium extending up to 6 mm beyond the acute pathologic RF lesion border as defined by NBT histochemical staining.
我们假设，射频（RF）导管消融术后的心肌损伤可能超出组织化学染色所定义的急性凝固性坏死区域。
在两只犬的左心室内进行了5次体内射频损伤，使用4毫米尖端的消融电极，调整射频功率以维持电极-组织界面温度在85摄氏度60秒。将损伤部位一分为二；一半损伤部位用硝基四氮唑蓝（NBT）染色，另一半进行电子显微镜检查。确定了从可见病理损伤边界向外延伸0-3毫米、3-6毫米和>6毫米的三个感兴趣区域。对每个区域的心肌超微结构损伤程度进行评分。电子显微镜显示，心肌细胞膜、线粒体、肌节、肌浆网和心肌细胞间连接存在明显异常，微血管损伤延伸至病理损伤边缘以外6毫米处。心肌细胞膜、心肌细胞间连接和微血管对热损伤特别敏感，而闰盘相对耐热。
射频导管消融导致心肌超微结构损伤，超出NBT组织化学染色所定义的急性病理射频损伤边界达6毫米。
