Cardiovascular MRI Characterization of the Arrhythmogenic Heart in Nonischemic Cardiomyopathy

项目总结 心血管疾病是发病率和死亡率的主要原因。心源性猝死(SCD)相关 室性心动过速或室颤(VT/VF)是结构性心脏患者死亡的50%原因 疾病。植入式心律转复除颤器(ICD)是一种公认的减少心律失常的治疗方法 死亡率。目前使用一级预防ICD的指南(即，没有室速/室颤病史但有风险的患者) 主要强调左心室射血分数(LVEF)。然而，只有一小部分ICD接受者 实际接受适当的ICD电击，导致不必要的成本和发病率。当有强大的 ICD降低冠心病患者死亡率的证据，一级预防的好处 非缺血性心肌病(NICM)患者的ICD表现较差。此外，SCD多发生在 目前不符合ICD资格的中度收缩功能障碍患者，进一步突出了 左心室射血分数在选择合适的ICD候选者方面的局限性。鉴于LVEF的局限性，有一个紧迫的问题 需要更好的风险分层策略来确定哪些NICM患者最有可能受益于ICD 心理治疗。我们的三个具体目标是：1)确定心脏磁共振(CMR)放射学的生物学基础 通过研究心内膜/心外膜电信号之间的相关性来确定心肌的表型 (EGM)和CMR放射组学标志物；2)研究CMR影像标志物，可以识别轻到 中度收缩功能障碍(左心室射血分数在36%至50%)有发生室性心律失常的风险，他们可能受益 预防ICD治疗，最终降低SCD总负担；以及3)确定NICM患者有左心室射血分数 正在接受一级预防ICD植入的35%，他们不太可能通过发展 结合CMR标记物的新型风险预测模型。准确识别有SCD风险的个人 将(A)通过向患有轻度至中度收缩功能障碍的患者提供ICD治疗来降低死亡率 以及(B)降低符合ICD条件的低风险患者的发病率和医疗费用 而且不太可能获得有价值的好处。

PROJECT SUMMARY Cardiovascular disease is the leading cause of morbidity and mortality. Sudden cardiac death (SCD) associated with ventricular tachycardia or fibrillation (VT/VF) is responsible for 50% of deaths in patients with structural heart disease. The implantable cardioverter defibrillator (ICD) is an established therapy for reducing arrhythmic mortality. Current guidelines for use of primary prevention ICD (i.e., patients without VT/VF history, but at risk) mainly emphasize left ventricular ejection fraction (LVEF). However, only a small percentage of ICD recipients actually receive appropriate ICD shocks, resulting in unnecessary costs and morbidity. While there is strong evidence that ICDs reduce mortality in patients with coronary artery disease, the benefit of primary prevention ICDs in patients with nonischemic cardiomyopathy (NICM) is less robust. Furthermore, SCD mostly occurs in patients with moderate systolic dysfunction who are currently not eligible for an ICD, further highlighting the limitations of LVEF to choose appropriate ICD candidates. Given the limitations of LVEF, there is a pressing need for better risk stratification strategies to identify which NICM patients are most likely to benefit from ICD therapy. Our three specific aims seek to 1) identify the biological basis of cardiac MR (CMR) radiomic phenotyping of the myocardium by investigating the association between endocardial/epicardial electrograms (EGM) and CMR radiomic markers; 2) investigate CMR imaging markers that can identify patients with mild to moderate systolic dysfunction (LVEF of 36% to 50%) at risk of ventricular arrhythmia, who are likely to benefit from prophylactic ICD therapy and ultimately reduce total SCD burden; and 3) identify NICM patients with LVEF 35% undergoing primary prevention ICD implantation who are less likely to benefit from ICD by developing a novel risk prediction model integrating CMR markers. Precise identification of individuals who are at risk of SCD will (a) reduce mortality by offering ICD therapy to patients with mild to moderate systolic dysfunction who are currently not eligible, and (b) reduce morbidity and healthcare costs in ICD-eligible patients who are at low risk of SCD and unlikely to obtain a worthwhile benefit.