[Early diastolic dysfunction of the left ventricle affected by hypertrophy and abnormal histopathology in hypertrophic cardiomyopathy].
In this study, we investigated correlations of left ventricular hypertrophy and its histopathology with diastolic dysfunction in patients with hypertrophic cardiomyopathy. Nine control subjects and 14 hypertrophic cardiomyopathy (HCM) patients with asymmetrical septal hypertrophy were evaluated. M-mode echocardiography was used to assess fractional shortening (FS), isovolumic relaxation time (IRT), and the left ventricular filling volume index during rapid and slow filling periods and atrial contraction period (RFVI, SFVI and ACVI). End-diastolic thickness of the interventricular septum and posterior wall was determined using biventriculography. Right ventricular endomyocardial biopsies were performed to calculate the diameters of myocytes, the percentage of fibrosis and the eccentricity e which indicates the degree of myocardial disarrangement including disorganization. The FS was normal in the two groups. The IRT of the HCM group was significantly greater and the RFVI significantly less than those of the controls. The left ventricular wall thickness, the diameters of myocytes and the percentage of fibrosis in the HCM group were significantly greater; and the eccentricity e was significantly less, suggesting that myocardial disarrangement was significantly more severe than that in the controls. Significant positive correlations were observed between the IRT and the wall thickness (r = 0.647), between the diameter of myocytes (r = 0.681) and the percentage of fibrosis (r = 0.628), and there was a significantly negative correlation between the IRT and the eccentricity e (r = -0.759). There was a significantly negative correlation between the RFVI and the wall thickness (r = -0.663); and a significantly positive correlation between the RFVI and the eccentricity e (r = 0.579). Multiple regression analyses showed that the diameter of myocytes, the percentage of fibrosis and the eccentricity e all correlated significantly with the IRT (R = 0.821) and the RFVI (R =0.604). The standard regression coefficients of the diameter of myocytes, the percentage of fibrosis and the eccentricity e were 0.253, 0.278 and -0.431 in respect to IRT, and those of the percentage of fibrosis and the eccentricity e were -0.204 and 0.469 in respect to RFVI, respectively. These results indicated that diastolic dysfunction in hypertrophic cardiomyopathy is related not only to the degree of left ventricular hypertrophy, but also to the degree of myocardial hypertrophy, increased interstitial fibrosis, and especially to myocardial disarrangement including disorganization.
Sugihara
N
N
Second Department of Internal Medicine, School of Medicine, Kanazawa University.
Shimizu
M
M
Suematsu
T
T
Horita
Y
Y
Shimizu
K
K
Ohsato
K
K
Shibayama
S
S
Nakao
T
T
Kitamura
M
M
Takeda
R
R
D000328:Adult; D006332:Cardiomegaly / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D003971:Diastole; D004452:Echocardiography; D004719:Endomyocardial Fibrosis / Q000473:pathology; D005260:Female; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D009206:Myocardium / Q000473:pathology*; D012044:Regression Analysis; D016277:Ventricular Function, Left