Ultrasound Diagnosis of Marfan Syndrome Complicated by Barlow Disease With Mitral Annular Disjunction: A Case Report

A 17-year-old male presented with intermittent palpitations for 6 months, acutely worsening over 24 h. Physical examination revealed Marfanoid features (arachnodactyly, positive thumb/wrist signs, pectus carinatum) and cardiac abnormalities (irregular rhythm, 3/6 systolic murmur with mid-late click). Echocardiography demonstrated: (1) Aortic sinu (AS) dilation (41 mm); (2) Bileaflet mitral valve prolapse (Barlow's Disease) with myxomatous degeneration (anterior leaflet 3.8 mm, posterior 4.2 mm); (3) Mitral annular disjunction (MAD, 13 mm gap). Transesophageal echo revealed left atrial appendage sluggish flow ("smoke-like echo") without thrombus. CTA confirmed aortic root aneurysm (42 mm) and right hydronephrosis. Electrocardiogram demonstrated paroxysmal atrial flutter. Diagnoses included Marfan syndrome (Ghent criteria), Barlow's Disease with MAD, paroxysmal atrial flutter, and obstructive hydronephrosis. The multidisciplinary team recommended staged interventions. Following catheter ablation for atrial flutter, the patient declined further procedures. Subsequent follow-up showed clinical stability.