Document Detail


In vivo measurement of mitral leaflet surface area and subvalvular geometry in patients with asymmetrical septal hypertrophy: insights into the mechanism of outflow tract obstruction.
MedLine Citation:
PMID:  20837895     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Analyzing the determinants of systolic anterior motion of the mitral valve and consequent left ventricular outflow tract (LVOT) obstruction in patients with asymmetrical septal hypertrophy requires a comprehensive 3-dimensional analysis of mitral leaflet (ML) area, papillary muscle (PM) geometry, and the distribution of left ventricular hypertrophy.
METHODS AND RESULTS: Real-time 3-dimensional echocardiography was performed in 47 patients with asymmetrical septal hypertrophy and 32 normal controls. Patients included 20 with resting LVOT obstruction (group I) and 27 without (group II). Customized software (Omni 4D) provided a validated measure of ML surface area, LVOT area, mitral annular area and nonplanarity, LVOT hypertrophy index by topography (percent area with wall thickness >16 mm), and 3-dimensional PM positions relative to annulus. ML area was more than twice as large in group I than normal and 1.4 times normal in group II (P<0.001). Group I patients were also characterized by higher LVOT hypertrophy index and medial and anterior displacements of both PMs, resulting in a shorter inter-PM distance. Independent determinants of LVOT obstruction were indexed total ML area (adjusted odds ratio, 5.651; 95% confidence interval, 1.573 to 20.304; P=0.008) and inter-PM distance (adjusted odds ratio, 0.416; 95% confidence interval, 0.203 to 0.854; P=0.0169). Minimal LVOT area during systole correlated well with peak LVOT pressure gradient (R(2)=0.83, P<0.001); its independent determinants were left ventricular end-systolic volume (P=0.0183), indexed total ML area (P=0.0108), inter-PM distance (P=0.0378), annular height (P=0.0047), and LVOT hypertrophy index (P=0.0098).
CONCLUSIONS: Myocardium is not the only tissue affected in patients with asymmetrical septal hypertrophy, and primary changes of the mitral apparatus, including ML area increase and PM displacement, are independent determinants of LVOT obstruction and provide a comprehensive mechanism that determines leaflet slack and anteriorly directed motion. Abnormal PM-mitral valve geometry assessed by real-time 3-dimensional echocardiography can provide reasonable new targets for individualized intervention.
Authors:
Dae-Hee Kim; Mark D Handschumacher; Robert A Levine; Yun-Sil Choi; Yun Jeong Kim; Sung-Cheol Yun; Jong-Min Song; Duk-Hyun Kang; Jae-Kwan Song
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2010-09-13
Journal Detail:
Title:  Circulation     Volume:  122     ISSN:  1524-4539     ISO Abbreviation:  Circulation     Publication Date:  2010 Sep 
Date Detail:
Created Date:  2010-09-29     Completed Date:  2010-10-18     Revised Date:  2014-09-18    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1298-307     Citation Subset:  AIM; IM    
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MeSH Terms
Descriptor/Qualifier:
Echocardiography, Three-Dimensional*
Female
Heart Rate
Heart Septum / pathology*,  physiopathology,  ultrasonography*
Heart Ventricles / abnormalities,  physiopathology,  ultrasonography
Humans
Male
Middle Aged
Mitral Valve / abnormalities,  ultrasonography*
Ventricular Dysfunction, Left / physiopathology,  ultrasonography*
Ventricular Outflow Obstruction / physiopathology*,  ultrasonography
Grant Support
ID/Acronym/Agency:
K24 HL067434/HL/NHLBI NIH HHS; K24 HL67434/HL/NHLBI NIH HHS; R01 HL072265/HL/NHLBI NIH HHS
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