146 LONG TERM LEFT VENTRICULAR POSTERIOR WALL ECHOCARDIO- GRAPHIC CHANGES IN DUCHENNE MUSCULAR DYSTROPHY

Abstract

Cardiac pathology in Duchenne's muscular dystrophy (DMD) is principally left ventricular posterior wall (LVPW) fibrosis. The aim of this study was to track long term LVPW echocardiographic (echo) changes in DMD. Echoes were recorded each 12 months from 19 boys with known DMD over 3 years and compared to controls. LVPW endo- and epicardium were digitized and % thickening and % thinning at standardized time intervals were determined; 15/19 had two-dimensional echoes. As previously reported, impaired diastolic relaxation was an early finding. The ratio of peak systolic LVPW to end diastolic LVPW was 2.06 (controls) to 1.83 (boys with DMD) (p<.01), but a given boy's ratio was not predictive. All 19 had LVPW thickness, adjusted for body size, below the control mean (p<.01). The major finding was that two wall pattern groups emerged: Group I-LVPW thickness increased normally with time and body surface area but at a low percentile curve. Group II-LVPW decreased progressively and in 4, almost no systolic LVPW thickening was found. Two-dimensional echoes were studied for change in cavity size during contraction. All Group I patients had normal two-dimensional echoes. All Group II patients had abnormally decreased LV free wall contraction. Sequential abnormal findings in DMD patients are impaired LVPW relaxation, decreased LVPW thickness in systole and end diastole, and a contraction impairment imaged with two-dimensional echo.