Houston Methodist DeBakey Heart & Vascular Center, Houston, Texas, USA.
Division of Cardiovascular Medicine, McGovern Medical School, University of Texas Health and Science Center at Houston, Houston, Texas, USA.
JACC Cardiovasc Imaging. 2021 Mar;14(3):573-584. doi: 10.1016/j.jcmg.2020.08.029. Epub 2020 Oct 29.
This study hypothesized that left ventricular (LV) enlargement in Barlow disease can be explained by accounting for the total volume load that consists of transvalvular mitral regurgitation (MR) and the prolapse volume.
Barlow disease is characterized by long prolapsing mitral leaflets that can harbor a significant amount of blood-the prolapse volume-at end-systole. The LV in Barlow disease can be disproportionately enlarged relative to MR severity, leading to speculation of Barlow cardiomyopathy.
Cardiac magnetic resonance (CMR) was used to compare MR, prolapse volume, and heart chambers remodeling in patients with Barlow disease (bileaflet prolapse [BLP]) and in single leaflet prolapse (SLP).
A total of 157 patients (81 with BLP, 76 with SLP) were included. Patients with SLP were older and more had hypertension. Patients with BLP had more heart failure. Indexed LV end-diastolic volume was larger in BLP despite similar transvalvular MR. However, the prolapse volume was larger in BLP, which led to larger total volume load compared with SLP. Increasing tertiles of prolapse volume and MR both led to an incremental increase in LV end-diastolic volume in BLP. Using the total volume load improved the correlation with indexed LV end-diastolic volume in the BLP group, which closely matched that of SLP. A multivariable model that incorporated the prolapse volume explained left heart chamber enlargement better than a MR-based model, independent of prolapse category.
The prolapse volume is part of the total volume load exerted on the LV during the cardiac cycle and could help explain the disproportionate LV enlargement relative to MR severity noted in Barlow disease.
本研究假设，通过考虑由二尖瓣反流（MR）和脱垂量组成的总容量负荷，可以解释巴氏病中的左心室（LV）扩大。
巴氏病的特征是二尖瓣叶长期脱垂，在收缩末期可容纳大量血液 - 脱垂量。巴氏病中的 LV 相对于 MR 严重程度不成比例地增大，导致巴氏心肌病的推测。
心脏磁共振（CMR）用于比较巴氏病（双瓣叶脱垂[BLP]）和单瓣叶脱垂（SLP）患者的 MR、脱垂量和心脏腔室重塑。
共纳入 157 例患者（81 例 BLP，76 例 SLP）。SLP 患者年龄较大，更多患有高血压。BLP 患者心力衰竭更多。尽管存在相似的跨瓣 MR，但 BLP 的 LV 舒张末期容积指数更大。然而，BLP 的脱垂量更大，导致与 SLP 相比总容量负荷更大。脱垂量和 MR 的递增三分位数均导致 BLP 的 LV 舒张末期容积指数增加。使用总容量负荷可改善 BLP 组与 LV 舒张末期容积指数的相关性，与 SLP 非常匹配。包含脱垂量的多变量模型比基于 MR 的模型更好地解释了左心腔扩大，独立于脱垂类别。
脱垂量是心脏周期内施加在 LV 上的总容量负荷的一部分，可以帮助解释巴氏病中相对于 MR 严重程度的不成比例的 LV 增大。
