Cardiac Ultrasound Laboratory (Y.N., P.B.B., H.A., J.P.D.-B., L.H., M.H.P., J.H., R.A.L.), Massachusetts General Hospital, Harvard Medical School, Boston.
Department of Radiology (V.B., G.H.), Massachusetts General Hospital, Harvard Medical School, Boston.
Circ Cardiovasc Imaging. 2023 Apr;16(4):e014963. doi: 10.1161/CIRCIMAGING.122.014963. Epub 2023 Apr 18.
The relation between ventricular arrhythmia and fibrosis in mitral valve prolapse (MVP) is reported, but underlying valve-induced mechanisms remain unknown. We evaluated the association between abnormal MVP-related mechanics and myocardial fibrosis, and their association with arrhythmia.
We studied 113 patients with MVP with both echocardiogram and gadolinium cardiac magnetic resonance imaging for myocardial fibrosis. Two-dimensional and speckle-tracking echocardiography evaluated mitral regurgitation, superior leaflet and papillary muscle displacement with associated exaggerated basal myocardial systolic curling, and myocardial longitudinal strain. Follow-up assessed arrhythmic events (nonsustained or sustained ventricular tachycardia or ventricular fibrillation).
Myocardial fibrosis was observed in 43 patients with MVP, predominantly in the basal-midventricular inferior-lateral wall and papillary muscles. Patients with MVP with fibrosis had greater mitral regurgitation, prolapse, and superior papillary muscle displacement with basal curling and more impaired inferior-posterior basal strain than those without fibrosis (<0.001). An abnormal strain pattern with distinct peaks pre-end-systole and post-end-systole in inferior-lateral wall was frequent in patients with fibrosis (81 versus 26%, <0.001) but absent in patients without MVP with basal inferior-lateral wall fibrosis (n=20). During median follow-up of 1008 days, 36 of 87 patients with MVP with >6-month follow-up developed ventricular arrhythmias associated (univariable) with fibrosis, greater prolapse, mitral annular disjunction, and double-peak strain. In multivariable analysis, double-peak strain showed incremental risk of arrhythmia over fibrosis.
Basal inferior-posterior myocardial fibrosis in MVP is associated with abnormal MVP-related myocardial mechanics, which are potentially associated with ventricular arrhythmia. These associations suggest pathophysiological links between MVP-related mechanical abnormalities and myocardial fibrosis, which also may relate to ventricular arrhythmia and offer potential imaging markers of increased arrhythmic risk.
已有研究报道，二尖瓣脱垂（MVP）患者的室性心律失常与纤维化之间存在相关性，但潜在的瓣膜相关机制尚不清楚。我们评估了 MVP 相关力学异常与心肌纤维化之间的关系，以及它们与心律失常的关系。
我们研究了 113 例 MVP 患者，这些患者均接受了超声心动图和钆心脏磁共振成像检查以评估心肌纤维化。二维和斑点追踪超声心动图评估了二尖瓣反流、二尖瓣前叶和乳头肌移位，以及相关的基底心肌收缩卷曲，并评估了心肌纵向应变。随访评估心律失常事件（非持续或持续室性心动过速或心室颤动）。
在 43 例 MVP 患者中观察到心肌纤维化，主要位于基底-中隔室下壁的基底外侧壁和乳头肌。与无纤维化的患者相比，有纤维化的 MVP 患者的二尖瓣反流、脱垂和基底卷曲时的前上乳头肌位移更大，下后基底应变更差（<0.001）。纤维化患者的下外侧壁常出现收缩期前和收缩期末有明显峰值的异常应变模式（81%比 26%，<0.001），但无 MVP 伴基底下外侧壁纤维化的患者中则无（n=20）。在中位数为 1008 天的中位随访期间，87 例 MVP 患者中有 36 例（>6 个月随访）发生了与纤维化、更大的脱垂、二尖瓣环分离和双峰应变相关的室性心律失常（单变量）。多变量分析显示，双峰应变比纤维化更能增加心律失常的风险。
MVP 中的基底下后壁心肌纤维化与 MVP 相关的心肌力学异常相关，而这些异常可能与室性心律失常有关。这些相关性表明 MVP 相关机械异常与心肌纤维化之间存在病理生理联系，也可能与室性心律失常有关，并为增加心律失常风险提供潜在的影像学标志物。
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