多学会解读心脏再同步治疗的新指南建议

根据美国心脏病学会基金会(ACCF)、美国心脏协会(AHA)和心律学会(HRS)9月10日在《循环》杂志在线发表的一项报告，新版心律失常器械治疗指南对心脏再同步治疗(CRT)的应用进行了多处更新(Circulation 2012 Sept. 10 [doi:10.1161/CIR.0b013e3182618569])。

指南起草小组主席、乔治华盛顿大学电生理学系主任Cynthia M. Tracy博士指出，上版指南于2008年发布，新版指南“评估和阐明了目前最佳实践，并将继续反映技术的进步”。

新指南最显著的变化是将CRT适用人群扩大至轻度心衰患者(NYHA心功能Ⅱ级)和预示不规则、慢性心率特殊ECG异常患者。此前这些患者被认为不宜接受CRT，但现有研究表明他们能够从中获益。CRT可延缓或避免心衰进一步恶化，从而改善患者生活质量。

此外，越来越多的证据表明，与ECG异常较轻的患者相比，ECG看似更为广泛、严重的患者受益可能更大，特别是左束支传导阻滞(LBBB)和QRS≥150 ms的患者，新指南也反映了上述变化。


这幅左侧位片显示出1例曾置入RV导线的患者置入CRT除颤器的最终位置。A：左心室导线指向后方。B：右心室ICD导线。C：之前置入的右心室导线。D：右心房导线。

在新指南中，CRT Ⅰ级推荐扩大至轻度心衰患者，但与其他所有Ⅰ级推荐患者一样，仅限于LBBB且QRS≥150 ms的患者。此外，CRT Ⅱb 级推荐增加了左心室射血分数(LVEF)≤30%、窦性心律、左束支传导阻滞且QRS≥150 ms以及功能性轻度心衰患者。

新指南对临终患者或需要放弃治疗患者心脏可植入性电子器械治疗的推荐意见更为详细，以便向照顾者提供处理这一日益增多的棘手问题的指导。心律失常患者生存时间越来越长，发生痴呆或恶性肿瘤等共病患者越来越多，而这些疾病可能比心律异常更为严重，这新变化促使了对现行指南进行相应更新。

自2008年版指南发布以来，对起搏器、植入式心律复转除颤器、CRT、植入式心电监测器以及植入式心血管检测器等心血管植入式电子器械的远程随访和监测也已发生了显著变化。通过电话传输心电监测系统对患者日常随访的标准方法存在局限性，已被认为 “过时”。而目前的远程监测系统采用双向遥测技术，通过编码和加密射频信号传输和接受信息。许多设备应用无线手机技术，无论患者在什么地方均可进行遥测，医生可通过互联网获得有关数据。几乎所有目前就诊时可获得的信息均可远程获得，包括电池电压、ICD充电时间、起搏百分比、感知灵敏度、自动测量起搏阈值、起搏和电击阻抗以及ECG记录的心律不齐事件。

新指南有关ICD植入治疗致心律失常性右心室发育不良/心肌症、无症状性遗传性心律失常综合征，对先心病心源性猝死和晚期心室功能不全、特发性室颤、短QT综合征、Brugada综合征或儿茶酚胺能多态性心室性心博过速患者一级预防的推荐没有变化。

更新后的指南还发表于《美国心脏病和心律学会杂志》上。美国胸外科学会(AATS)、美国心衰学会(HFSA)和胸外科医师协会(STS)也参与了该指南修订工作。新指南全文参见ACC、AHA和HRS网站。

在利益冲突方面，起草小组成员如与某一章节有关的行业和实体存在特殊关系，则取消其对该章节的表决资格。

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By: MARY ANN MOON, Cardiology News Digital Network

Updated guidelines on device-based treatment for cardiac rhythm abnormalities include several changes in the use of cardiac resynchronization therapy, according to a report issued jointly by the American College of Cardiology Foundation, the American Heart Association, and the Heart Rhythm Society and published online Sept. 10 in Circulation.

The most significant changes are the expanded use of cardiac resynchronization therapy (CRT) to include patients with mild heart failure (New York Heart Association class II) and to patients with particular ECG abnormalities indicating irregular, slow rhythms, said Dr. Cynthia M. Tracy, chair of the guideline writing group and director of electrophysiology at George Washington University, Washington, and her associates.

"These are patients who had previously been excluded from receiving CRT, but studies have shown they can benefit from this procedure. It can really improve their lives by delaying or avoiding worsening heart failure," she said in a press statement accompanying the update.

The guidelines also now reflect the "growing evidence that patients with the widest, most abnormal–looking ECG potentially benefit most, compared with patients whose ECG is less abnormal." In particular, patients with left bundle branch block and a QRS duration of 150 milliseconds or more appear to benefit greatly from CRT, she noted.

The updated guidelines are also being published in the Journal of the American College of Cardiology and Heart Rhythm. They were developed in collaboration with the American Association for Thoracic Surgery, the Heart Failure Society of America, and the Society of Thoracic Surgeons.

The original guidelines on devise-based treatment of cardiac rhythm abnormalities were issued in 2008. The updated guidelines "extend and clarify current best practices and will continue to evolve as technology advances," Dr. Tracy added.

In the updated guidelines, the class I recommendations for CRT have been expanded to include patients with milder heart failure. But these, as with all other class I recommendations, are limited to those with left bundle branch block and a QRS of 150 milliseconds or more. In addition, a class IIb recommendation for CRT has been added for patients with aleft ventricular ejection fraction (LVEF) of 30% or less, an ischemic etiology of their heart failure (HF), sinus rhythm, left bundle branch block with a QRS duration of 150 milliseconds or more, and functionally mild HF, Dr. Tracy and her colleagues said (Circulation 2012 Sept. 10 [doi:10.1161/CIR.0b013e3182618569]).

Regarding terminal care, the recommendations "on management of cardiovascular implantable electronic devices in patients nearing the end of life or requesting withdrawal of therapy were expanded upon ... in an effort to provide guidance to caregivers dealing with this increasingly prevalent and difficult issue," according to the update.

This change was prompted by the observation that more such patients are surviving longer – long enough to develop comorbid conditions such as dementia or malignancy, which may take precedence over their rhythm abnormality.

Remote follow-up and monitoring of cardiovascular implantable electronic devices – including pacemakers, implantable cardioverter defibrillators, CRTs, implantable loop recorders, and implantable cardiovascular monitors – also has changed dramatically since the 2008 guidelines were formulated. "The standard approach was routine in-person office follow-up supplemented by transtelephonic monitoring with limited remote follow-up," but that approach is now considered "dated."

In contrast, "contemporary remote monitoring uses bidirectional telemetry with encoded and encrypted radiofrequency signals, allowing transmission and receipt of information from [these devices]." Many devices use wireless cellular technology to extend telemetry links to wherever the patient is located and to allow clinicians to access the data through the Internet. Almost all of the information that could be obtained in an in-office visit now is available remotely, including battery voltage, ICD charge time, percent pacing, sensing thresholds, automatically measured pacing thresholds, pacing and shock impedance, and stored arrhythmia events with ECGs, Dr. Tracy and her colleagues said.

No changes have been made in guideline recommendations regarding ICD implantation for arrhythmogenic right ventricular dysplasia/cardiomyopathy, asymptomatic genetic arrhythmia syndromes, primary prevention of sudden cardiac death in patients with congenital heart disease and advanced ventricular dysfunction, idiopathic ventricular fibrillation, short QT syndrome, Brugada syndrome, or catecholaminergic polymorphic ventricular tachycardia.

The full text of the update guidelines is available on the websites of the American College of Cardiology, the American Heart Association, and the Heart Rhythm Society.

Writing group members are required to recuse themselves from voting on sections to which their specific relationships with industry and other entities may apply.