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 Fernando Morcerf A1 Ernesto E. Salcedo A1 Wayne Siegel YR 1976 UL http://www.ccjm.org/content/43/3/163.abstract AB