RT Journal Article SR Electronic T1 Echocardiographic determination of the etiology of severe mitral regurgitation JF Cleveland Clinic Journal of Medicine JO Cleve Clin J Med FD Cleveland Clinic SP 163 OP 174 VO 43 IS 3 A1 Morcerf, Fernando A1 Salcedo, Ernesto E. A1 Siegel, Wayne YR 1976 UL http://www.ccjm.org/content/43/3/163.abstract AB