726-3 Functional Mitral Regurgitation Correlates with Incomplete Mitral Valve Closure not Left Ventricular Sphericity in Active Myocarditis

Incomplete mitral valve (MV) closure and LV sphericity correlates with functional MR in chronic dilated cardiomyopathy. To assess the mechanism of MR in active myocarditis (M) echocardiograms performed within 5.7 ± 1.2 days of initial RV biopsy in 27 pts with histologically proven M enrolled in the Myocarditis Treatment Trial were analyzed. M pts were stratified into those with mild MR (≤1 +, n = 14) and moderate MR (≥2+, n = 13). LV volume (vol) was measured and a sphericity index (SI) calculated. A value approaching 1 represents increased sphericity. Mitral annular (MA) diameter (d), the distance (DIS) between MV leaflet coaptation and MA plane, and the area enclosed by MVand MA (MVarea) were measured and compared to 20 normal controls. MAd (em) DlS(cm) MVarea (cm 2 ) LVvol (cc/m 2 ) SI Control 23 ± 02 0.32 ± 013 034 ± 013 49.5 ± 79 0.36 ± 0.05 ≤1+ MR 3.1 ± 0.4 * 0.60 ± 0.14 * 1.2 ± 0.45 * 79.7 ± 28.9 * 0.47 ± 0.10 * ≥2+ MR 3.9 ± 0.5 * 0.96 ± 0.18 * 23 ± 0.64 * 78.3 ± 29 * , † 0.48 ± 0.09 * , † * p l 0.0001 compared to control † p = N5 compared to ≤l + MR Conclusion In active M, functional MR does not correlate with increasing LV sphericity. Incomplete MV closure and MA dilatation are more important correlates of MRseverity.