International Circulation: Long term failure of ICD remains a major problem including the failure of leads. Could you give us a brief summary of types and reasons of lead failure?

　　《国际循环》：ICD的长期使用寿命始终是一个主要问题，包括导线的故障。您能谈谈ICD导线故障的类型和原因吗?

　　Harry Mond: The ICD lead is the Achilles heal， the weak point of an ICD and the most likely part to fail. We are now implanting ICDs in patients who are otherwise well but have a high risk of sudden death. One thing that we want to do is not making the patients worse. It is quite clear from the literature that there is a fairly high incidence of failure of ICD leads. Initially this was because of the insulation failure of the outer coating， but more recently we have realized that failures can occur due to problems with the conductors. The insulation materials that we use are silicon rubber and polyurethane， both of which are found wanting and are not ideal. Please remember these are the standard materials available in any industry and are not specific or unique materials to either an ICD or even a pacing lead. The conductors also fail because of the coil failure but the other component， which is a cable， can be prone to failure as we find for the first time. The reasons for lead failure are many and complex. Maybe the design of the lead in some cases is insufficient and needs to be altered. There has been an enormous amount of work trying to improve the design of ICD leads to overcome these deficiencies. Also， new materials are becoming available which are， hopefully， unique to the pacemaker industry that will make leads much better for the future.

　　Harry mond教授：植入式心律转复除颤器ICD的导线故障是这一技术的阿喀琉斯之踵，导线是ICD最可能出现故障的部分。从文献资料可以非常清楚地看到，ICD电极导线故障发生率相当高。最初故障发生是因为电极导线外周包被绝缘层的缺陷，但是最近我们意识到故障也可能发生于导体。我们用的绝缘材料是硅胶和聚氨酯，这两种材料都发现有一定的缺陷而且都不是最理想的。这些材料是标准的工业材料，并不是ICD和起搏器导线的专用特殊材料。导体故障可能是因为线圈故障，或是目前新发现的另一种组件线缆的问题。电极导线故障的原因是多方面的也是复杂的。或许在某些病例中导线的设计是不适当的，已经有大量的工作努力来改善ICD导线的设计，从而克服种种缺陷和不足。另外，仅用于起搏器工业的新材料也将面世，希望使导线在未来的质量越来越好。