Department of Cardiology, Division of Electrophysiology, Ochsner Medical Center, New Orleans, Louisiana.
J Cardiovasc Electrophysiol. 2020 May;31(5):1137-1146. doi: 10.1111/jce.14395. Epub 2020 Mar 1.
Sudden cardiac death is a substantial cause of mortality in patients with cardiomyopathy, but evidence supporting implantable cardioverter-defibrillator (ICD) implantation is less robust in nonischemic cardiomyopathy (NICM) than in ischemic cardiomyopathy. Improved risk stratification is needed. We assessed whether absolute quantification of stress myocardial blood flow (sMBF) measured by positron emission tomography (PET) predicts ventricular arrhythmias (VA) and/or death in patients with NICM.
In this pilot study, we prospectively followed patients with NICM (left ventricular ejection fraction ≤ 35%) and an ICD who underwent cardiac PET stress imaging with sMBF quantification. NICM was defined as the absence of angiographic obstructive coronary stenosis, significant relative perfusion defects on imaging, coronary revascularization, or acute coronary syndrome. Endpoints were appropriate device therapy for VA and all-cause mortality. Subgroup analysis was performed in patients who had no prior history of VA (ie, the primary prevention population).
We followed 37 patients (60 ± 14 years, 46% male) for 41 ± 23 months. The median sMBF was 1.56 mL/g/min (interquartile range: 1.00-1.82). Lower sMBF predicted VA, both in the whole population (hazard ratio [HR] for each 0.1 mL/g/min increase: 0.84, P = .015) and in the primary prevention subset (n = 27; HR for each 0.1 mL/g/min increase: 0.81, P = .049). Patients with sMBF below the median had significantly more VA than those above the median, both in the whole population (P = .004) and in the primary prevention subset (P = .046). Estimated 3-year VA rates in the whole population were 67% among low-flow patients vs 13% among high-flow patients, and 39% vs 8%, respectively, among primary-prevention patients. sMBF did not predict all-cause mortality.
In patients with NICM, lower sMBF predicts VA. This relationship may be useful for risk stratification for ventricular arrhythmia and decision making regarding ICD implantation.
心脏性猝死是心肌病患者死亡的主要原因，但与缺血性心肌病相比，非缺血性心肌病（NICM）中植入式心脏复律除颤器（ICD）植入的证据并不充分。需要进行更好的风险分层。我们评估了正电子发射断层扫描（PET）测量的应激心肌血流量（sMBF）的绝对定量是否可预测 NICM 患者的室性心律失常（VA）和/或死亡。
在这项前瞻性研究中，我们对接受了心脏 PET 应激成像和 sMBF 定量检查的 NICM（左心室射血分数≤35%）和 ICD 患者进行了前瞻性随访。NICM 的定义为无血管造影阻塞性冠状动脉狭窄、影像学上存在明显的相对灌注缺损、冠状动脉血运重建或急性冠状动脉综合征。终点是 VA 的适当设备治疗和全因死亡率。在无 VA 既往史的患者（即一级预防人群）中进行了亚组分析。
我们对 37 名患者（60±14 岁，46%为男性）进行了 41±23 个月的随访。中位 sMBF 为 1.56 mL/g/min（四分位间距：1.00-1.82）。sMBF 降低预示着 VA，无论是在整个人群中（每增加 0.1 mL/g/min 的风险比 [HR]：0.84，P=.015）还是在一级预防亚组中（n=27；每增加 0.1 mL/g/min 的 HR：0.81，P=.049）。sMBF 低于中位数的患者发生 VA 的明显多于 sMBF 高于中位数的患者，这在整个人群中（P=.004）和一级预防亚组中（P=.046）均如此。整个人群中低流量患者的估计 3 年 VA 发生率为 67%，而高流量患者为 13%，一级预防患者分别为 39%和 8%。sMBF 与全因死亡率无关。
在 NICM 患者中，sMBF 降低预示着 VA。这种关系可能有助于进行室性心律失常的风险分层，并有助于决定是否植入 ICD。
