Histology Course A III 3 Department of Pathology, University of Zurich Histology Course

A III 3 normal myocard; left ventricular hypertrophy HE  
  ICD-10: I51.7
48-year-old male died in an accident.

76-year-old female suffered from arterial hypertension and died because of massive cerebral hemorrhage (specimens from autopsy).
-Two sections of the left ventricular wall are shown, the one to the right exhibits slight, the one to left severe hypertrophy of the myocardium.
- In cardiac hypertrophy the following histological characteristics can be observed: (1) Increased cross-sectional areas of myocytes due to an increased number of sarcomeres; (2) Nuclei are enlarged (as a scale compare with erythrocytes or nuclei of fibroblasts; (3) The capillary density is decreased compared to normal; (4) A marked fibrosis may be present. (5) The muscle fibers display branching, so called muscle fiber disarray. This feature is reminiscent of hypertrophic cardiomyopathy.
- In the section to the right the slight enlargement of nuclei can be appreciated. However, the other features described above are not present. In contrast, the section to the left displays all features stated.

Pathogenesis: Increased pressure load due to an increased resistance (arterial hypertension, aortic valve stenosis).
Macroscopy: Increased wall thickness of the left ventricle. The thickened muscle may reduce the cavity diameter. The weight of the heart is increased above normal levels. Pressure-overload leads to so called concentric hypertrophy.