《国际循环》：心律失常与心源性猝死的管理而言，我们需遵循指南。 指南中呈现的新思路与新趋势备受临床医生关注，在指南制定过程 中您如何考量？

　　Silvia Priori 教授：是的，心源性猝死是一个非常复杂的问题，这主要是因为大多数心源性猝死发生于既往无已知心脏病的患者中。心源性猝死可能是心脏病的首发表现形式。这就意味着，作为心脏病学家，我们需要更快速地识别心脏疾病的早期征象。具体来说，应该及时发现哪些心脏疾病的早期征象呢？从指南可见，几乎所有的心脏疾病均可导致心脏骤停。这其中包括瓣膜病、心肌梗死、急性心肌缺血、慢性心力衰竭、遗传性心脏病。此外，可导致心肌损害的神经肌肉疾病等其他疾病也可导致心脏骤停。因此，可导致心源性猝死的原因非常多，要想有效预防心源性猝死，我们真的需要提高心脏科医生、其他科室医生对心源性猝死病因的认识。对心脏病学家而言，要做到早期发现急性心肌梗死、伴有心悸及晕厥的窦性心律失常，尽早发现虽然目前生活正常但可能会发生意外情况的伴有心肌病或离子通道病的年轻人。心源性猝死的预防涉及多个方面，正是因为如此相关指南的是非常长的。但是，我认为指南的相关推荐一直在不断努力总结进一步减少猝死的方法和途径。

　　《国际循环》：植入式心律转复除颤器的有效性及安全性如何？

　　Silvia Priori教授：植入式心律转复除颤器（ICD）是一级预防中挽救猝死高危人群生命的一种非常重要的设备，在心脏骤停幸存者的二级预防中作用更重要。对儿科患者而言，也不例外，其也是非常重要的。但是，就成年人、婴儿及儿童而言，考虑或决定植入除颤器还是需要考虑到一些差异。那就是，在年轻患者中其并发症（主要但不仅限于导线相关并发症）发生风险更高。目前，还没有儿科专用导线，故儿童植入ICD时通常需要从现有导线中选择适合细小静脉的导线。因此，与成人相比，儿童植入ICD时通常更容易发生导线断裂。电生理学家、心律失常专家及儿科心脏病学家均强力推荐在对年轻人植入ICD前仔细评估其风险。非常有趣的是，我们的指南此次对皮下ICD作了推荐。皮下ICD可由心室除颤器发出电击，无需经静脉植入导线，仅需植入皮下定位在心脏周围。人们对其成为年轻患者的首选治疗寄予了很好的期望。目前，对幼儿而言，皮下ICD的尺寸还是有些过大，还需要开展更多研究。未来，将有更多相关数据发布。

　　《国际循环》：长QT综合征等心律失常综合征患者的风险分层是非常重要的。能否请您谈一下这方面的内容？

　　Silvia Priori教授：确实如此，风险分层对决定是否进行去神经治疗以及是否植入ICD至关重要。目前有些疾病的风险分层已经非常明确，而有些疾病的风险分层则尚处于早期起步阶段。就你刚才所提到的长QT综合征而言，我们对其危险分层了解的相对较多。患者的QT间期越长，其风险越高。对QT间期>500ms者，即使其没有症状，其也存在较高的心脏事件发生风险，因此一定要尽快给予β受体阻滞剂治疗。但是，对有些长QT间期综合征患者，尤其是有晕厥发作病史及存在遗传基因的患者，我们真的需要考虑植入ICD。我之所以提到遗传基因，是因为若患者存在特定基因突变，其疾病很可能更多是良性的，如长QT综合征1型患者；而存在其他基因突变时，则存在较高风险，如长QT综合征2型及长QT综合征3型患者。根据QT间期的持续时间、基因甚至是基因突变位置及性别，我们可以根据指南推荐的流程来对患者进行风险分层。就Brugada综合征而言，目前我们识别高危患者的识别能力尚处于早期发展阶段。我们知道，若患者大部分时间存在自发性心电图异常，则存在较高风险。有人曾提出采用程序电刺激对患者进行分层，但其敏感性及特异性仍饱受争议。至于Brugada综合征患者何时应植入ICD，尚存在很多挑战及有待解答之处。例如就儿茶酚胺敏感性多形性室性心动过速（CPVT）而言，很多幼儿会出现症状，目前的趋势是应用β受体阻滞剂。但是，指南也提到和推荐应用氟卡尼等钠通道阻滞剂，该类药物与β受体阻滞剂一样也具有较好的疗效，有助于减少ICD的应用。鉴于CPVT患者行运动负荷试验会出现心律失常，可采用运动负荷试验来简化危险分层。此外，运动负荷试验可对其治疗具有指导价值，有助于我们评价患者对治疗的反应，确定单纯应用β受体阻滞剂是否已足够、是否需要加用氟卡尼或是否需要植入ICD。

　　IC : With cardiac arrhythmia and sudden cardiac death management we follow guidelines which come up with new ideas and new trends. This is a matter of concern for clinicians.

　　SP : Yes， the prevention of sudden cardiac death is a complicated issue，  mainly because the majority of sudden death occurs in patients that did not have a recognized cardiac disease. It might be， and it is， the first manifestation of a cardiac disease. This means as cardiologists we need to be much faster and prompt to identify early sign of a cardiac condition. Which cardiac conditions? We know as the guidelines show clearly a lot of substrate can lead to cardiac arrest. Almost everything-valvular disease， cardiac infarction， acute ischemia， but also the chronic phase of heart failure， genetic substrate， and then there are all the conditions that are not even cardiovascular diseases like the neuromuscular diseases that also are associated with cardiac pathology. So it is a broad field. But to fight our battle against sudden cardiac death， we really need to influence cardiologists， the community， and the broad range of other kind of physicians. For the cardiologist it really is a matter of early identification of patients with acute MI， with sinus arrhythmias like palpitation and syncope， and to try really to identify also the young people who may have unexpectedly， even if they have a normal life or substrate， that it could be a cardiac myopathy or a channelopathy. So it is a very multifaceted topic and that is why the guidelines are so long. But I think that the recommendations are attempting really to draw pathways and approaches that may contribute to further reduce sudden death.

　　IC: What about the efficacy and safety of the implantable cardioverter defibrillator?

　　SP: Yes， the defibrillator is a very important device for saving individuals with high risk of sudden death in primary prevention， and even more importantly for persons who have already survived a cardiac arrest. Therefore it is secondary prevention. When it comes to pediatric patients， there is no exceptions so the ICD is extremely important. However， the difference between deciding to implant a defibrillator in an adult， or in an infant， or a young individual in pediatric case， is the fact that the younger the patient is the higher the complications. This is mainly but not only related to the risk of complications for the leads. There are no pediatric leads， so when it comes to implanting children there is always to design an adaptation of the existing leads for a smaller body and smaller veins especially. As a consequence， these patients have more often than the adult lead fractures. And the international community of electrophysiologists， arrhythmic and pediatric cardiologists strongly recommend very careful identification， that the risk is there before thinking of an ICD in a young person. Interestingly so， our guidelines this time start introducing recommendations about the subcutaneous ICD. The subcutaneous ICD is a device that can shock from a ventricular defibrillation， but without using leads that are introduced in the vein. They are actually positioned around the heart but under the skin. There is high expectation that this approach may actually become one of the preferred alternatives for the young individuals. Right now more studies are required， the size of the defibrillators for subcutaneous defibrillator is still too large for the very young children， but the technologies there and there is high expectation as they said that this will become the preferred way for implanting young individuals. There will be more data to come.

　　IC: Management of risk stratification of patients with syndromes like arrhythmic syndromes are important such as long QT syndrome. Could you explain this please?

　　SP: Yes， risk stratification is important for the decision to implant an ICD， but also for the decision of starting therapy of performing denervation of all the approaches that are used in patients with channelopathies. Risk stratification is strong in some of these conditions， and still quite a preliminary and early stage in other disease. You mentioned long QT syndrome. Well in long QT syndrome we know quite a bit. The patients with the longer QT are the patients at higher risk. So when we see someone with a corrected QT above 500， we immediately know that even if the patient is asymptomatic they have a higher probability of developing a cardiac event over life. We definitely want beta blockers but in some of these patients， especially if they have had fainting episodes， especially if they have certain genetic substrates we really want to consider the ICD. I mentioned the genetics， because in long QT if you have mutation in certain genes， you have a more benign form， like the long QT syndrome type 1. If you have mutations in other genes， for example the long QT 2 and long QT 3 patients then there is a higher risk. When you combine the duration of the QT and the genetic substrate， and even the position of the mutation and even the gender of the individuals， you can develop algorithm that we have proposed in our guidelines that are quite useful to decide how to stratify these patients. On the other side， in individuals with Brugada syndrome we are still at an early phase of identification of the patients at higher risk. We know the one that has an abnormal ECG most of the time， spontaneously without doing any provocation and has had a syncopatic result， are at higher risk. We have some group that has proposed programmed electrical stimulation for restratification，  yet the sensitivity and specificity of that is highly debated. It is more challenging to decide when we want to implant individuals and there is a quite big gray zone. In catecholaminergic polymorphic ventricular tachycardia for example， where very young children become symptomatic， the tendency is to use beta blockers.  But in these guidelines we are also mentioning and supporting the use of Flecainide sodium channel blocker that can compliment very well the efficacy of beta blockers，  therefore reduce the need for the use of the ICD in these patients. In CPVT the stratification is facilitated if you wish， by the fact that when you put these patients on the treadmill， they manifest the arrhythmias， so we have a test that can give us the sense of how good the therapy is and can guide us when the beta blocker is enough if we need to add Flecainide; or despite having all the drugs we really need to consider the ICD.