Okafor Joseph, Kanaganayagam Gajen Sunthar, Patel Ketna
Cardiology Department, Chelsea and Westminister NHS Foundation Trust, 369 Fulham Rd, Chelsea, London SW10 9NH, UK.
Cardiology Department, Imperial College Healthcare NHS Trust, The Bays, South Wharf Road, St Mary's Hospital, London W2 1NY, UK.
Eur Heart J Case Rep. 2020 Jan 31;4(1):1-4. doi: 10.1093/ehjcr/ytz244. eCollection 2020 Feb.
Accessory mitral valve tissue (AMVT) is a rare anomaly that can be detected in the first decade. It is associated with other congenital cardiac abnormalities, such as ventricular septal defect. When detected in adulthood, it is usually an incidental finding on echocardiography. Symptomatic individuals can present with breathlessness, syncope, and features of distal tissue embolization. Cardiac surgery is indicated in those with significant left ventricular outflow tract obstruction.
A 45-year-old man without any significant medical history was referred due to an abnormal electrocardiogram. He was asymptomatic from a cardiac perspective. Echocardiography revealed the presence of a giant mobile mass attached to the anterior mitral valve leaflet and prolapsing into the left ventricular outflow tract (LVOT). This was classified as Type IIB2 AMVT. As there was no dynamic outflow tract obstruction on subsequent treadmill stress echocardiography, and in the absence of other coexistent congenital abnormality, surgical excision was not performed.
It is important to exclude significant obstruction when a large AMVT is seen to be prolapsing into the LVOT. Three-dimensional echocardiography is the tool of choice for anatomical classification and to assess for concomitant congenital cardiac abnormalities.
二尖瓣附属组织（AMVT）是一种罕见的异常情况，可在儿童期被发现。它与其他先天性心脏异常有关，如室间隔缺损。在成年期被发现时，通常是在超声心动图检查中偶然发现。有症状的个体可能出现呼吸困难、晕厥以及远端组织栓塞的特征。对于有严重左心室流出道梗阻的患者，建议进行心脏手术。
一名45岁男性，无重大病史，因心电图异常前来就诊。从心脏角度来看，他没有症状。超声心动图显示，一个巨大的可移动团块附着于二尖瓣前叶，并脱垂至左心室流出道（LVOT）。这被归类为IIB2型AMVT。由于在随后的平板运动负荷超声心动图检查中没有动态流出道梗阻，且不存在其他并存的先天性异常，因此未进行手术切除。
当发现一个大的AMVT脱垂至LVOT时，排除严重梗阻很重要。三维超声心动图是进行解剖学分类和评估是否存在先天性心脏异常的首选工具。
