Sf. Yiu et al., Determinants of the degree of functional mitral regurgitation in patients with systolic left ventricular dysfunction - A quantitative clinical study, CIRCULATION, 102(12), 2000, pp. 1400-1406
Citations number
36
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
Background-Functional mitral regurgitation (FMR) occurs with a structurally
normal valve as a complication of systolic left ventricular dysfunction (L
VD). Determinants of degree of FMR are poorly defined; thus, mechanistic th
erapeutic approaches to FMR are hindered.
Methods and Results-In a prospective study of 21 control subjects and 128 p
atients with LVD (defined as ejection fraction <50%, mean 31+/-9%) in sinus
rhythm, we quantified simultaneously by echocardiography the effective reg
urgitant orifice (ERO) of FMR by using 2 methods: mitral deformation (valve
and annulus) and left ventricular (LV) global (volumes, stress, function,
and sphericity) and local (papillary muscle displacements and regional wall
motion index) remodeling. A wide range of ERO (15+/-14 mm(2), 0 to 87 mm(2
)) was observed, unrelated to ejection fraction (P=0.32). The major determi
nant of ERO was mitral deformation, ie, systolic valvular tenting and annul
ar contraction in univariate (r=0.74 and r=-0.61, respectively; both P<0.00
01) and multivariate (both P<0.0001) analyses, independent of global LV rem
odeling. Systolic valvular tenting was strongly determined by local LV alte
rations, particularly apical (r=0.75) and posterior (r=0.70) displacement o
f papillary muscle, with confirmation in multivariate analysis (both P<0.00
01), independent of LV volumes, function, and sphericity.
Conclusions-The presence and degree of FMR complicating LVD are unrelated t
o the severity of LVD. Local LV remodeling (apical and posterior displaceme
nt of papillary muscles) leads to excess valvular tenting independent of gl
obal LV remodeling. In turn, excess tenting and loss of systolic annular co
ntraction are associated with larger EROs. These determinants of FMR warran
t consideration for specific approaches to the treatment of FMR complicatin
g LVD.