Division of Cardiovascular Diseases, University of Cincinnati College of Medicine, and E. L. Saenger Radioisotope Laboratory, University Hospital of Cincinnati, Cincinnati, Ohio 45267-0542, USA.
JACC Cardiovasc Imaging. 2010 Jan;3(1):101-10. doi: 10.1016/j.jcmg.2009.07.013.
Sudden cardiac death remains the leading cause of death in the U.S. A left ventricular ejection fraction (LVEF)<30% to 35% identifies a population of patients at increased risk for sudden cardiac death. Once identified, an implantable cardioverter-defibrillator (ICD) is effective in reducing the occurrence of sudden cardiac death. Yet in a substantial proportion of patients who receive an ICD based on reduced LVEF, the device never delivers therapy. Furthermore, the majority of patients who die suddenly do not qualify for ICD placement under current LVEF-based criteria in the guidelines. This review considers the potential role of cardiac imaging in improving the selection of patients most likely to benefit from an ICD. The presence of myocardial scar and/or unrevascularized myocardial ischemia provides an important substrate for the occurrence of potentially fatal ventricular arrhythmias. The presence of clinical heart failure further increases the risk of ventricular arrhythmia. The sympathetic nervous system provides an important trigger for major arrhythmic events, both through global overactivity and through regional heterogeneity of sympathetic activity. A mismatch of myocardial perfusion and innervation may pose a particularly great risk. Imaging modalities provide unique opportunities to investigate the anatomic and pathophysiologic substrates, as well as the triggering effects of cardiac sympathetic innervation. Combining imaging and electrophysiologic modalities offers promise for improved accuracy in future selection of patients with heart failure for ICD placement.
心脏性猝死仍然是美国的主要死亡原因。左心室射血分数（LVEF）<30%至 35%确定了一群发生心脏性猝死风险增加的患者。一旦确定，植入式心脏复律除颤器（ICD）可有效降低心脏性猝死的发生。然而，在很大一部分接受基于降低 LVEF 的 ICD 的患者中，该设备从未提供治疗。此外，大多数发生突然死亡的患者不符合当前指南中基于 LVEF 的标准对 ICD 进行定位的条件。这篇综述考虑了心脏成像在改善最有可能从 ICD 中受益的患者选择方面的潜在作用。心肌瘢痕和/或未再血管化的心肌缺血为潜在致命性室性心律失常的发生提供了重要的基质。临床心力衰竭的存在进一步增加了室性心律失常的风险。交感神经系统通过整体过度活跃和交感神经活动的局部异质性，为主要心律失常事件提供了重要的触发因素。心肌灌注和神经支配的不匹配可能构成特别大的风险。成像方式为研究解剖和病理生理基质以及心脏交感神经支配的触发作用提供了独特的机会。结合成像和电生理方式有望提高未来对心力衰竭患者进行 ICD 定位的准确性。
