二尖瓣环解离（Mitral annular disjunction，简称MAD）是二尖瓣（MV）铰链点的房性移位，特别是沿后二尖瓣瓣叶，导致不均匀的血流进入左心室，引起慢性纤维化变化、恶性心律失常，甚至突发心脏骤停。一些研究表明MAD是正常心脏形态的一部分；然而，起源仍然存在争议。MAD常见于MV脱垂和黏液样退变MV病变。近20%的病例中，MAD也可以独立发生。MAD在正常心脏中的患病率根据成像方式和定义MAD的截断点的不同，从8.6%到96%不等。经胸超声心动图通常是最初的筛查检测方法，但由于其对MAD的低敏感性，易于漏诊。更高级的成像，特别是心脏磁共振成像（cardiac MRI），是诊断MAD和风险分层的金标准。MAD是恶性心律失常的独立预测因子。在MAD患者中，风险分层基于诊断时的年龄、以往晕厥发作、室性早搏、乳头肌纤维化和纵向解离距离。大多数无症状患者采取保守治疗；然而，对于高风险或有症状的MAD患者，应考虑射频消融，以减少室性心律失常和心脏性猝死的风险。版权所有©2023 Wolters Kluwer Health, Inc. 保留一切权利。

Mitral annular disjunction (MAD) is the atrial displacement of the mitral valve (MV) hinge point, especially along the posterior mitral leaflet, which leads to inhomogeneous blood flow into the left ventricle, causing chronic fibrotic changes, malignant arrhythmias, and even sudden cardiac arrest. Some studies suggest that MAD is a part of normal heart morphology; however, the origin is still controversial. MAD commonly occurs with MV prolapse and myxomatous degenerative MV disease. In almost 20% of cases, MAD can occur independently as well. The prevalence of MAD in normal hearts varies from 8.6% to 96%, depending on the imaging modality and the cutoff used to define MAD. Transthoracic echocardiography is often the initial screening test, but the low sensitivity of transthoracic echocardiography to identify MAD makes it easy to miss the diagnosis altogether. More advanced imaging, especially cardiac MRI, is the gold standard for diagnosing MAD and risk stratification. MAD is an independent predictor of malignant arrhythmia. Among patients with MAD, risk stratification is based on the age at diagnosis, previous syncopal attacks, premature ventricular contractions, papillary muscle fibrosis, and longitudinal disjunction distance. Most asymptomatic patients are managed conservatively; however, radiofrequency ablation should be considered in patients with high-risk or symptomatic MAD due to the risk of ventricular arrhythmias and sudden cardiac death.Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.