Second Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine , Kitakyushu , Japan.
Division of Cardiology, Asan Medical Center, University of Ulsan College of Medicine , Seoul , South Korea.
Am J Physiol Heart Circ Physiol. 2019 Mar 1;316(3):H629-H638. doi: 10.1152/ajpheart.00618.2018. Epub 2018 Dec 21.
Progressive superior shift of the mitral valve (MV) during systole is associated with abnormal papillary muscle (PM) superior shift in late systolic MV prolapse (MVP). The causal relation of these superior shifts remains unclarified. We hypothesized that the MV superior shift is related to augmented MV superiorly pushing force by systolic left ventricular pressure due to MV annular dilatation, which can be corrected by surgical MV plasty, leading to postoperative disappearance of these superior shifts. In 35 controls, 28 patients with holosystolic MVP, and 28 patients with late systolic MVP, the MV coaptation depth from the MV annulus was measured at early and late systole by two-dimensional echocardiography. The PM tip superior shift was monitored by echocardiographic speckle tracking. MV superiorly pushing force was obtained as MV annular area × (systolic blood pressure - 10). Measurements were repeated after MV plasty in 14 patients with late systolic MVP. Compared with controls and patients with holosystolic MVP, MV and PM superior shifts and MV superiorly pushing force were greater in patients with late systolic MVP [1.3 (0.5) vs. 0.9 (0.6) vs. 3.9 (1.0) mm/m, 1.3 (0.5) vs. 1.2 (1.0) vs. 3.3 (1.3) mm/m, and 487 (90) vs. 606 (167) vs. 742 (177) mmHg·cm·m, respectively, means (SD), P < 0.001]. MV superior shift was correlated with PM superior shift ( P < 0.001), which was further related to augmented MV superiorly pushing force ( P < 0.001). MV and PM superior shift disappeared after surgical MV plasty for late systolic MVP. These data suggest that MV annulus dilatation augmenting MV superiorly pushing force may promote secondary superior shift of the MV (equal to late systolic MVP) that causes subvalvular PM traction in patients with late systolic MVP. NEW & NOTEWORTHY Late systolic mitral valve prolapse (MVP) is associated with mitral valve (MV) and papillary muscle (PM) abnormal superior shifts during systole, but the causal relation remains unclarified. MV and PM superior shifts were correlated with augmented MV superiorly pushing force by annular dilatation and disappeared after surgical MV plasty with annulus size and MV superiorly pushing force reduction. This suggests that MV annulus dilatation may promote secondary superior shifts of the MV (late systolic MVP) that cause subvalvular PM traction.
收缩期二尖瓣（MV）进行性向上移位与收缩晚期 MV 脱垂（MVP）中异常的乳头肌（PM）向上移位有关。这些向上移位的因果关系仍不清楚。我们假设 MV 向上移位与收缩期左心室压力引起的 MV 环扩张导致的 MV 向上推挤力增加有关，这种力可以通过 MV 成形术来纠正，导致术后这些向上移位的消失。在 35 名对照者、28 名全收缩期 MVP 患者和 28 名收缩晚期 MVP 患者中，通过二维超声心动图在收缩早期和晚期测量 MV 瓣环至 MV 瓣叶的结合深度。通过超声心动图斑点追踪监测 PM 尖端向上移位。MV 向上推挤力作为 MV 环面积×（收缩压-10）获得。在 14 例收缩晚期 MVP 患者中，在 MV 成形术后重复进行这些测量。与对照组和全收缩期 MVP 患者相比，收缩晚期 MVP 患者的 MV 和 PM 向上移位以及 MV 向上推挤力更大[1.3（0.5）比 0.9（0.6）比 3.9（1.0）mm/m，1.3（0.5）比 1.2（1.0）比 3.3（1.3）mm/m，和 487（90）比 606（167）比 742（177）mmHg·cm·m，均为平均值（标准差），P<0.001]。MV 向上移位与 PM 向上移位相关（P<0.001），PM 向上移位进一步与 MV 向上推挤力增加相关（P<0.001）。MV 成形术后收缩晚期 MVP 的 MV 和 PM 向上移位消失。这些数据表明，MV 环扩张增加 MV 向上推挤力可能会导致 MV 的继发性向上移位（相当于收缩晚期 MVP），从而导致收缩晚期 MVP 患者的瓣下 PM 牵拉。
