Blanchard S M, Walcott G P, Wharton J M, Ideker R E
Department of Medicine, Duke University Medical Center, Durham, North Carolina.
Pacing Clin Electrophysiol. 1994 Dec;17(12 Pt 1):2315-35. doi: 10.1111/j.1540-8159.1994.tb02382.x.
Nearly 80% of patients with coronary artery disease who have map-directed surgery for control of ventricular tachycardias require no drug therapy to prevent recurrences, while fewer than 50% of patients undergoing catheter ablation have similar outcomes. Catheter ablation will fail if arrhythmogenic sites are incompletely ablated by lesions that are too small or too far away from the reentrant pathway or if all arrhythmogenic sites are not identified. The underlying assumptions used to guide site selection are that: (a) ventricular tachycardias arise from reentrant mechanisms; (b) monomorphic ventricular tachycardias with similar QRS morphologies arise from the same pathway; (c) the ventricular tachycardia initiated during the procedure represents the patient's spontaneous arrhythmia; (d) the endocardial site that should be ablated can be identified from cardiac activation maps produced during induced ventricular tachycardia or from ancillary techniques; and (e) the patient has only one or two reentrant pathways. Relying on incorrect assumptions may account for the difference in success rates. Patients may have similar appearing ventricular tachycardias that arise from different pathways, and the entire thin layer of viable tissue between the infarct and the endocardium may contain many reentrant pathways. Some ventricular tachycardias may arise from the myocardium away from the endocardium, while others may arise from the epicardium. Small lesions may not be large enough to eliminate all possible reentrant pathways. Catheter ablation may be less successful because the lesions are inadequate, the assumptions guiding the selection of arrhythmogenic tissue are incorrect, or all arrhythmogenic sites are not identified. The primary reason catheter ablation is less successful than surgery in the treatment of ventricular tachycardias is that catheter ablation does not ablate as much tissue as is removed by surgery. The success rate of catheter ablation probably can be improved if the amount of tissue ablated is increased.
接受标测指导下手术以控制室性心动过速的冠心病患者中，近80%无需药物治疗来预防复发，而接受导管消融的患者中，只有不到50%能取得类似的效果。如果致心律失常部位未被过小或离折返路径过远的消融灶完全消融，或者所有致心律失常部位未被识别，导管消融将会失败。用于指导部位选择的基本假设是：(a)室性心动过速由折返机制引起；(b)具有相似QRS形态的单形性室性心动过速起源于同一途径；(c)术中诱发的室性心动过速代表患者的自发心律失常；(d)可从诱发室性心动过速期间产生的心脏激动标测图或辅助技术中识别出应消融的心内膜部位；(e)患者只有一条或两条折返路径。依赖错误的假设可能是成功率存在差异的原因。患者可能有起源于不同途径但外观相似的室性心动过速，梗死灶与心内膜之间的整个存活组织薄层可能包含许多折返路径。一些室性心动过速可能起源于心内膜以外的心肌，而其他一些可能起源于心外膜。小的消融灶可能不足以消除所有可能的折返路径。导管消融可能不太成功，原因可能是消融灶不充分、指导致心律失常组织选择的假设不正确，或者所有致心律失常部位未被识别。导管消融在治疗室性心动过速方面不如手术成功的主要原因是，导管消融所消融的组织不如手术切除的多。如果增加消融的组织量，导管消融的成功率可能会提高。
