Shape index and eccentricity index are measures of left ventricular morphology. Although both measures can be quantified with any stress imaging modality, they are not routinely evaluated during clinical interpretation. We assessed their independent associations with major adverse cardiovascular events (MACE), including measures of poststress change in shape index and eccentricity index. Methods: Patients undergoing SPECT myocardial perfusion imaging between 2009 and 2014 from the Registry of Fast Myocardial Perfusion Imaging with Next-Generation SPECT (REFINE SPECT) were studied. Shape index (ratio between the maximum left ventricular diameter in short axis and ventricular length) and eccentricity index (calculated from orthogonal diameters in short axis and length) were calculated in end-diastole at stress and rest. Multivariable analysis was performed to assess independent associations with MACE (death, nonfatal myocardial infarction, unstable angina, or late revascularization). Results: In total, 14,016 patients with a mean age of 64.3 ± 12.2 y (8,469 [60.4%] male were included. MACE occurred in 2,120 patients during a median follow-up of 4.3 y (interquartile range, 3.4–5.7). Rest, stress, and poststress change in shape and eccentricity indices were associated with MACE in unadjusted analyses (all P < 0.001). However, in multivariable models, only poststress change in shape index (adjusted hazard ratio, 1.38; P < 0.001) and eccentricity index (adjusted hazard ratio, 0.80; P = 0.033) remained associated with MACE. Conclusion: Two novel measures, poststress change in shape index and eccentricity index, were independently associated with MACE and improved risk estimation. Changes in ventricular morphology have important prognostic utility and should be included in patient risk estimation after SPECT myocardial perfusion imaging.

形状指数和偏心率指数是左心室形态的测量。尽管这两种测量方法都可以通过任何应力成像方式进行量化，但在临床解释过程中不会对它们进行常规评估。我们评估了它们与主要不良心血管事件 (MACE) 的独立关联，包括形状指数和偏心率指数的应激后变化测量。方法：对 2009 年至 2014 年间接受下一代 SPECT 快速心肌灌注成像 (REFINE SPECT) 登记的 SPECT 心肌灌注成像患者进行研究。形状指数（短轴最大左心室直径与心室长度之间的比率）和偏心率指数（根据短轴和长度的正交直径计算）在应激和静息时计算舒张末期。进行多变量分析以评估与 MACE（死亡、非致命性心肌梗死、不稳定心绞痛或晚期血运重建）的独立关联。结果：总共纳入 14,016 名患者，平均年龄为 64.3 ± 12.2 岁（8,469 名男性 [60.4%]）。在中位随访 4.3 年期间，2,120 名患者发生 MACE（四分位数间距，3.4-5.7）。在未经调整的分析中，形状指数、应力和应力后变化与偏心率指数均与 MACE 相关（全部P < 0.001），但是，在多变量模型中，只有应力后形状指数变化（调整后风险比，1.38； P < 0.001）。偏心指数（调整后的风险比，0.80； P = 0.033）仍然与 MACE 相关。 结论：形状指数和偏心率指数的应力后变化这两种新测量方法与 MACE 独立相关，并改进了风险评估。心室形态的变化具有重要的预后效用，应纳入 SPECT 心肌灌注成像后的患者风险评估中。