40. Hypertrophic cardiomyopathy

The marked area is where you’ll find the evidence for hypertrophic cardiomyopathy. Note how it’s between the artery on the upper left and the big vein (?) on the lower right.

Staining: HE

Organ: Myocardium

Description: We can see the normal signs of hypertrophic myocardium: interstitial fibrosis, enlarged nuclei and (some) lipofuscin pigment. In an area almost in the exact middle of the slide is an area where the myocardial cells have lost their orientation.

Diagnosis: Hypertrophic cardiomyopathy

Causes: Genetic defects

Theory:

Hypertrophic cardiomyopathy has the same microscopic morphology as simple hypertrophic myocardium, but also has areas where there is loss of orientation. If you have trouble recognizing the slide you can remember the blocky appearance of the upper right corner of the slide.

Close-up of that area. Note how the myocardial fibres have no direction. Compare with the picture below

From the same slide, but from an area without loss of orientation

Normal signs of hypertrophic myocardium