Department of Radiology, UZ Leuven, Leuven, Belgium.
JACC Cardiovasc Imaging. 2012 Jul;5(7):702-11. doi: 10.1016/j.jcmg.2012.03.011.
The aim of this study was to analyze the geometric pattern of hypertrophy (HT) in patients with asymmetrical septal hypertrophic cardiomyopathy (HCM) using cardiac magnetic resonance (CMR) and to test the hypothesis that at least in some patients, the HT follows a longitudinal spiral pattern.
The highly heterogeneous phenotypic expression of HCM is a well-known phenomenon. CMR has emerged as a robust 3-dimensional (3D) tomographic imaging technique that is increasingly used to explore phenotypic expression.
Short-axis cine CMR was used to study the 3D extent of HT (i.e., radial, circumferential, and longitudinal extent, as well as the relation between circumferential and longitudinal extent). Inclusion criteria were septal wall thickness (WT) ≥15 mm and septal to free wall WT ratio >1.3.
CMR was performed in 132 patients. Maximal WT was 22 ± 5 mm, with a circumferential extent of 131 ± 51°, and a longitudinal extent of 64 ± 19%, resulting in a hypertrophied left ventricular (LV) surface of 26 ± 15%. Linear regression analysis showed in 86% of patients a consistent course of HT along the longitudinal direction. The HT invariably started at the basal anteroseptum and rotated, except in 2 patients, in a counterclockwise direction (CC-spiral patients) with a mean global rotation of 116 ± 68° (range 5° to 350°). After the CC-spiral patients were divided according to magnitude of rotation quartiles (Q1: 5° to 70°, Q2: 75° to 105°, Q3: 110° to 150°, and Q4: 155° to 350°), Q4 patients were significantly older and had more LV outflow tract obstruction and hypertension than patients without the spiraling pattern. In 11 patients, continuation of HT into an apical form of HCM was found.
Using 3D analysis, we found that the majority of patients with asymmetrical septal HCM in fact showed a spiral pattern of HT following a counterclockwise (or "left-handed") spiral trajectory. The variation in magnitude of rotation among patients, however, was highly variable. Further research is warranted to better understand the significance of the current findings, in particular to relate them to the genetic and morphological substrate, hemodynamic consequences, and patient outcome.
本研究旨在通过心脏磁共振（CMR）分析不对称性间隔肥厚型心肌病（HCM）患者的肥厚（HT）的几何形态，并验证如下假说，即至少在某些患者中，HT 呈纵向螺旋状。
HCM 的高度异质性表型表达是一种众所周知的现象。CMR 已成为一种强大的三维（3D）断层成像技术，越来越多地用于探索表型表达。
使用短轴电影 CMR 研究 HT 的 3D 程度（即径向、圆周和纵向程度，以及圆周和纵向程度之间的关系）。纳入标准为间隔壁厚度（WT）≥15mm 且间隔与游离壁 WT 比>1.3。
共对 132 例患者进行了 CMR 检查。最大 WT 为 22±5mm，圆周程度为 131±51°，纵向程度为 64±19%，导致左心室（LV）肥大表面为 26±15%。线性回归分析显示，86%的患者 HT 沿纵向呈一致的方向发展。HT 始终从基底前间隔开始，并旋转，除了 2 例患者呈逆时针方向（CC 螺旋患者）旋转，平均总旋转度为 116±68°（范围 5°至 350°）。在根据旋转四分位数（Q1：5°至 70°，Q2：75°至 105°，Q3：110°至 150°，Q4：155°至 350°）将 CC 螺旋患者进行分组后，Q4 患者比无螺旋模式患者年龄更大，且更易发生 LV 流出道梗阻和高血压。在 11 例患者中，发现 HT 向心尖型 HCM 延续。
使用 3D 分析，我们发现大多数不对称性间隔 HCM 患者的 HT 实际上呈逆时针（或“左旋”）螺旋状。然而，患者之间的旋转幅度变化差异很大。需要进一步研究以更好地理解当前发现的意义，特别是将其与遗传和形态学基础、血液动力学后果和患者预后联系起来。
