Diagnosis and management of parachute mitral valve and supravalvar mitral ring.

The results of investigation in 5 children with congenital deformities of the mitral valve region characteristic of the 'parachute mitral valve complex' were reviewed. Three patients had parachute mitral valve, i had supravalvar mitral ring, and i had both these lesions. Associated anomalies included ventricular septal defect, double outlet right ventricle, subaortic stenosis, bicuspid aortic valve, and coarctation of the aorta. Clinical presentation depended on which abnormality was dominant. However, all patients had clinical and haemodynamic evidence of mitral valve disease: stenosis in 4 patients and incompetence in i. In i patient the single, hypertrophied papillary muscle obstructed left ventricular ejection, mimicking hypertrophic obstructive cardiomyopathy. Parachute mitral valve produced a specific angiocardiographic abnormality, afilling defect during diastole shaped like an egg-timer in the lateral left ventricular angiogram. This was produced by non-opacified blood posterior to the mitral leaflets and chordae tendineae converging towards the filling defect produced by the enlarged, single papillary muscle. Supravalvar mitral ring produced a thin, crescentic, filling defect between the left atrium and ventricle, seen in the lateral view during opacification of the ventriclefrom the atrium. Careful preoperative assessment of the relative importance of these multiple anomalies allowed successful surgical correction of the significant lesions in the 4 patients operated on. Of 3 patients with parachute mitral valve, 2 required mitral valve replacement. In i of these a supravalvar ring was also excised. In the other patient with supravalvar mitral stenosis, excision of the ring alone relieved mitral obstruction adequately.