Isolated Mitral Cleft in Trisomy 21: An Initially 'Silent' Lesion.

Congenital cardiac anomalies are common in trisomy 21, and transthoracic echocardiogram within the first month of life is recommended. While a cleft mitral valve associated with atrioventricular septal defect has been well defined in this population, the prevalence of isolated mitral valve cleft has not been previously reported. The aim of our study was to define the occurrence of isolated mitral cleft in the first echocardiogram of patients with trisomy 21. This retrospective chart review examined echocardiographic data on all Trisomy 21 patients <1 year of age obtained during January 1, 2010, to May 1, 2014, at our institution. Images were reviewed by one of the authors with no knowledge of the official diagnosis. In addition to evaluation for isolated mitral valve cleft, data obtained included presence of additional congenital heart defects and need for surgical intervention. A total of 184 patients (median age 5 days) were identified. Isolated mitral cleft was identified in 12 patients (6.5 %). Four were diagnosed retrospectively (33 %). Only one had mitral regurgitation on initial echocardiogram. Seven required surgery for closure of ventricular septal defects. Isolated mitral cleft is present in an important number of neonates with Trisomy 21. Mitral regurgitation is often absent in the neonatal period and should not be used as a reliable indicator of absence of valve abnormality. Careful attention should be directed toward the mitral valve during the first echocardiogram to exclude an isolated cleft, which can lead to progressive mitral regurgitation.