Echocardiographic Characteristics and Detection Rate of Symptomatic Uni-Leaflet Mitral Valve Malformations in a...

Congenital uni-leaflet mitral valve (ULMV), a rare cardiac anomaly caused by embryonic atrioventricular valve dysplasia, lacks established epidemiological data and imaging diagnostic criteria for symptomatic cases. This study systematically analysed echocardiographic characteristics of ULMV and, for the first known time, elucidated the detection rate of symptomatic ULMV in a consecutive Chinese cohort.

A single-centre retrospective cohort study was conducted, enrolling 137,214 consecutive symptomatic cardiac patients who underwent transthoracic echocardiography at The First People's Hospital of Jingzhou, China (2019-2023). ULMV screening followed the American Society of Echocardiography guidelines using standardised multiplanar imaging (parasternal long-axis, basal-apical short-axis, and apical 4-chamber views). Positive cases were confirmed by two blinded associate chief physicians.

Eight symptomatic ULMV cases were identified, yielding a detection rate of 5.83 per 100,000 (95% confidence interval 2.53-11.48 per 100,000). Cases were categorised as isolated (Type Ⅰ, n=4) or complex (Type Ⅱ, with concomitant anomalies, n=4) for comparative analysis. Compared with Type Ⅰ, Type Ⅱ ULMV was associated with significantly greater median effective regurgitant orifice area (0.60 vs 0.145 cm²; p=0.029), regurgitant volume (65 vs 12.5 mL; p=0.029), leaflet prolapse (4.5 vs 2.5 mm; p=0.029), and incidence of cardiac enlargement (100% vs 0%; p=0.029).

The detection rate of symptomatic ULMV in this consecutive Chinese cohort is low. Echocardiography reveals two distinct subtypes with significantly different haemodynamic and morphological profiles. The complex subtype is uniformly associated with severe sequelae, highlighting the importance of detailed anatomical assessment for risk stratification.