Abstract
Cardiac status was prospectively evaluated non-invasively in 20 male children, each with clinical, biochemical, electromyographic and muscle-biopsy evidence of Duchenne's progressive muscular dystrophy. A nonejection systolic click, confirmed by phonocardiography, was identified in 7 patients (3 with midsystolic murmur as well) and suggested the presence of MVP syndrome. Echocardiography supported this diagnosis in all 7 patients and in 4 others without systolic click. An abrupt midsystolic posterior motion (> 3mm) was noted in 5 patients, while a smooth, pansystolic, anteriorly concave (“hammock-like”) posterior motion of the leaflet > 3mm from the CD line was recorded for all 11 patients. Additional findings were: multiple sequence lines in 6 patients and posterior coaptation of the mitral leaflet near the left atrial wall in 6.
Pathogenesis of these abnormal findings was studied by detailed macroscopic, histologic and ultrastructural examination of the heart in a patient with a nonejection systolic click and echo evidence of the syndrome. The entire heart was perfused and fixed within 2 hours of death with 2.5% glutaraldehyde at 4°C for 4 hours. The most characteristic ultrastructural findings were multifocal areas with total loss of thick as well as thin myofilaments but preservation of the transverse “T” system. These degenerative changes affected predominantly the left ventricular posterobasal area and posterior papillary muscle. Mitral valve leaflets were normal.
We conclude i) a high prevalence of MVP syndrome exists in Duchenne's dystrophy ii) the syndrome in these patients is an expression of cardiomyopathy rather than an isolated dystrophic involvement of the mitral valve leaflets.
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Sanyaj, S., Leung, R., Tierney, R. et al. 156 MITRAL VALVE PROLAPSE (MVP) SYNDROME IN DUCHENNE'S PROGRESSIVE MUSCULAR DYSTROPHY. Pediatr Res 12 (Suppl 4), 389 (1978). https://doi.org/10.1203/00006450-197804001-00161
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DOI: https://doi.org/10.1203/00006450-197804001-00161