Assessment of papillary muscle function using myocardial velocity gradient derived from tissue Doppler echocardiography.
Papillary muscle (PM) function is vital to mitral valve competence. However, quantitative assessment of the function is difficult due to the complexity of the mitral apparatus. We hypothesized that myocardial velocity gradient (MVG) could be applied to assess PM function. We studied MVG-PM in 123 patients with left ventricular dysfunction (ejection fraction <40%) and 123 normal subjects throughout a systolic phase. MVG-PM in normal subjects was significantly higher than in patients with left ventricular dysfunction (3.6/s vs 1.4/s, p <0.001). MVG-PM reached its peak at early systole and correlated well with PM thickening (r = 0.89). MVG-PM in patients with left ventricular dysfunction correlated with the severity of apical tenting of the mitral valve (y = 0.8x - 0.07, r = 0.72). Patients with lower MVG-PM tended to have less severe mitral regurgitation (y = 0.03x + 0.3, r = 0.83). PM contractility can be quantitatively assessed by calculating the MVG derived from tissue Doppler imaging. PM dysfunction, indicated by lower MVG-PM, decreased mitral leaflet tethering, thus paradoxically decreasing mitral regurgitation severity. MVG is a useful tool in determining the role of PM in functional mitral regurgitation.
Khankirawatana
Banthit
B
Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, 68198-1165, USA. bkhankir@unmc.edu
Khankirawatana
Suwanee
S
Mahrous
Heidi
H
Porter
Thomas R
TR
D000368:Aged; D001783:Blood Flow Velocity; D018618:Echocardiography, Doppler, Color / Q000379:methods*; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging / Q000503:physiopathology*; D010210:Papillary Muscles / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology*