Left ventricular pannus causing inflow obstruction late after mitral valve replacement for endocardial fibroelastosis.

A case of mitral stenosis following mitral valve replacement in a patient with endocardial fibroelastosis is reported. A 14-year-old boy presented with cardiac failure. He had been diagnosed as having endocardial fibroelastosis at the age of 7 months and had undergone resection of endocardial fibrous tissue in the left ventricle at that time. Five years later his mitral valve was resected owing to mitral stenosis, with Bjork-Shiley valve replacement. Cross-sectional echocardiography on this admission showed restrictive left ventricular inflow due to a thickened immobile prosthetic valve with severely dyskinetic left ventricle (ejection fraction 8%). The electrocardiogram showed atrioventricular reentry tachycardia. Despite direct current cardioversion and continual amiodarone infusion he suffered a cardiac arrest and died 12 days after admission. Postmortem examination showed left ventricular endocardial fibroelastosis with severe inflow obstruction due to the formation of a complete fibrous ring of pannus/fibrosis around the prosthetic margin on the ventricular aspect of the left ventricle. This complication has not previously been described in children after mitral valve replacement.