Heart, Lung, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA.
Eur J Nucl Med Mol Imaging. 2014 Mar;41(3):529-35. doi: 10.1007/s00259-013-2608-3. Epub 2013 Nov 9.
Many patients presently receiving cardiac resynchronization therapy (CRT) do not respond. A disproportionate number of nonresponders have ischemic cardiomyopathy, with significant left ventricular (LV) scar burden. Current selection criteria, such as electrocardiography or echocardiography, may not reliably portray the magnitude of CRT-remediable LV contraction dyssynchrony. Although phase analysis of gated single photon emission computed tomography (SPECT) image data is increasingly appreciated as a tool for quantifying dyssynchrony, its use in the setting of scar has not been adequately evaluated.
Consecutive patients with ischemic (ICM, n = 50) or nonischemic (NICM, n = 39) cardiomyopathy underwent SPECT imaging prior to receiving CRT. In each patient, phase analysis of the raw images was performed to yield a phase standard deviation (PSD), an index which varies directly with the magnitude of dyssynchrony. ICM patient image data were also reanalyzed after scarred segments were stripped away.
Raw image analysis demonstrated that PSD was significantly larger among ICM (57 ± 17°) than NICM (35 ± 13°, p < 0.001) patients. Among ICM patients, PSD after stripping of scarred segments was significantly decreased (40 ± 13°, p < 0.001). Signals emanating from scarred segments were of low amplitude and presented a random pattern, suggestive of noise rather than indicating contraction.
PSD values may be spuriously increased by scar. These findings may be important when using SPECT in selecting ischemic cardiomyopathy patients for CRT.
目前许多接受心脏再同步治疗（CRT）的患者没有反应。相当数量的无反应者患有缺血性心肌病，伴有明显的左心室（LV）瘢痕负担。目前的选择标准，如心电图或超声心动图，可能无法可靠地描绘 CRT 可纠正的 LV 收缩不同步的程度。尽管门控单光子发射计算机断层扫描（SPECT）图像数据的相位分析越来越被认为是量化不同步的工具，但它在瘢痕中的应用尚未得到充分评估。
连续 50 例缺血性（ICM）或非缺血性（NICM）心肌病患者在接受 CRT 治疗前接受 SPECT 成像。在每个患者中，对原始图像进行相位分析以产生相位标准偏差（PSD），该指数与不同步的程度直接相关。还对 ICM 患者的图像数据进行了分析，去除了瘢痕段。
原始图像分析表明，PSD 在 ICM（57±17°）患者中明显大于 NICM（35±13°，p<0.001）患者。在 ICM 患者中，去除瘢痕段后 PSD 明显降低（40±13°，p<0.001）。源自瘢痕段的信号幅度较低且呈随机模式，提示为噪声而非收缩。
瘢痕可能会使 PSD 值假性升高。当使用 SPECT 选择缺血性心肌病患者进行 CRT 时，这些发现可能很重要。
