Royal Brompton and Harefield NHS Trust, London, United Kingdom.
Harefield Hospital, Harefield, Uxbridge, UB9 6JH, United Kingdom.
J Nucl Cardiol. 2020 Dec;27(6):2273-2279. doi: 10.1007/s12350-018-01574-y. Epub 2019 Jan 2.
Phase analysis of gated single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy provides a measure of left ventricular dyssynchrony and may have applications for identifying patients suitable for cardiac resynchronisation therapy. Phase analysis is typically described in degrees of cardiac cycle, less intuitive to cardiologists familiar with ECGs. We assessed the relationship between time and degrees, to determine whether they are interchangeable.
399 patients underwent normal stress-only SPECT myocardial perfusion imaging using Technetium-99m-tetrofosmin. Data analysis used QGS software (Cedars Sinai) calculating bandwidth and standard deviation. Heart rate, age, gender, stress modality, and ejection fraction were analyzed for their relation to phase variables. 13 patients were excluded for conduction abnormalities including right and left bundle branch block and ventricular pacing. Heart rate was strongly correlated to bandwidth and standard deviation measured in time, but unrelated when measured in degrees. Although bandwidth measured by time and degrees were strongly correlated with each other this relationship was not perfect (correlation coefficient 0.87, P < .001). The addition of heart rate to the model explained most of the residual variation between the two. The results for standard deviation were similar.
In patients with normal myocardial perfusion and QRS duration bandwidth measured by degrees is not directly interchangeable with time in milliseconds. However most of the variation is explainable by heart rate, which predominantly affects measures of time rather than degrees. We would propose that although the values are less intuitive to cardiologists, normal ranges for phase measured in degrees are potentially more robust.
门控单光子发射型计算机断层扫描（SPECT）心肌灌注闪烁显像的时相分析提供了一种衡量左心室不同步的方法，可能有助于确定适合心脏再同步治疗的患者。相位分析通常以心动周期的度数来描述，对于熟悉心电图的心脏病专家来说不太直观。我们评估了时间和度数之间的关系，以确定它们是否可以互换。
399 例患者接受了使用 99mTc-甲氧基异丁基异腈的正常应激-only SPECT 心肌灌注成像。使用 QGS 软件（西达斯西奈）分析数据，计算带宽和标准差。分析心率、年龄、性别、应激方式和射血分数与相位变量的关系。13 例因包括右束支和左束支传导阻滞及心室起搏在内的传导异常而被排除在外。心率与时间测量的带宽和标准差呈强相关，但与度数测量的无相关性。尽管时间和度数测量的带宽彼此之间具有很强的相关性，但这种关系并不完美（相关系数 0.87，P<0.001）。将心率添加到模型中可以解释两者之间大部分剩余的差异。标准差的结果相似。
在心肌灌注正常且 QRS 持续时间的患者中，以度数测量的带宽与以毫秒为单位的时间不能直接互换。然而，心率可以解释大部分的变异，心率主要影响时间而不是度数的测量。我们建议，尽管这些数值对心脏病专家来说不太直观，但以度数测量的正常范围可能更稳健。
