[Relationships between distribution of disorganized cardiac muscle cells and disease state in hypertrophic cardiomyopathy].
Congestive heart failure is rare in hypertrophic cardiomyopathy (HCM). Therefore, disorganization of the cardiac muscle cells, a histological hallmark of HCM, has not been associated with reduced ventricular contraction. We performed a clinicopathological study of 18 patients with HCM to determine whether disorganization contributes to dilatation and impaired contraction of the ventricles, resulting in affecting the disease condition. The subjects were classified into Group A (11 patients) without dilatation of the ventricular cavities after formalin fixation at autopsy (left 11.9 ml and right 19.1 ml), Group B (two patients) with dilatation of the left but without of the right ventricular cavity (left 31.9 ml and right 25.6 ml), and Group C (five patients) with biventricular dilatation (left 38.6 ml and right 36.8 ml). Various parameters were compared among the three groups. The mean age of the patients was 44.0 years for Group A, 18.5 for Group B and 10.2 section for Group C. The mean cardiothoracic ratio was 51.8% (n = 7) for Group A, 53% (n = 1) or Group B, and 74.0% section for Group C. Obstruction of the left ventricular outflow tract was observed in 100% (n = 8) of the Group A patients, in 0% section of the Group B patients, and in 20.0% section of the Group C patients. The mean left ventricular ejection fraction was 81.0% (n = 5) in Group A, 65.5% in Group B and 39.0% section (n = 2) in Group C. None of the Group A patients had chronic congestive heart failure, whereas all Group C patients died of this condition. Using transverse and longitudinal tissue sections from the ventricles, and a quantitative method employing light microscopy, we determined the area of the myocardium characterized by disorganization and interstitial fibrosis. Septal disorganization was observed in 67.4%, 83.4% and 91.1% section of the transverse sections in Groups A, B and C, respectively, and in 17.0%, 24.9% and 63.5% section of the longitudinal sections in the respective groups. As for the left ventricular free wall, disorganization involved 21.2%, 69.4% section and 90.8% section of the transverse sections and 15.9%, 34.9% section and 38.1% section of the longitudinal sections in Groups A, B and C, respectively. In the right ventricular free wall, there was disorganization in 17.7%, 20.4% and 84.3% section of the transverse sections in 12.4%, 11.5% and 57.0% section of the longitudinal sections in the respective groups.(ABSTRACT TRUNCATED AT 400 WORDS)
D000293:Adolescent; D000328:Adult; D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000473:pathology* / Q000503:physiopathology; D002423:Cause of Death; D002648:Child; D002675:Child, Preschool; D004719:Endomyocardial Fibrosis / Q000473:pathology; D005260:Female; D006333:Heart Failure / Q000209:etiology / Q000473:pathology; D006346:Heart Septum / Q000473:pathology; D006352:Heart Ventricles / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D009206:Myocardium / Q000473:pathology*; D013318:Stroke Volume; D014694:Ventricular Outflow Obstruction / Q000209:etiology