Hypertrophic cardiomyopathy ischemia

Overview
There is extensive periarteriolar fibrosis that results in microvascular dysfunction and an impairment in coronary flow reserve in patients with hypertrophic obstructive cardiomyopathy.

Histopathology
Compared to normal arterioles on the left, the arterioles from a patient with hyertension (middle) show moderate periarteriolar thickening and fibrosis. Shown on the right is a patient with HCM in which there is even more signficant periarteriolar thickening and fibrosis. This thickening of the wall of the intramyocardial arterioles leads to an increased wall/lumen ratio, subendocardial ischemia and impaired coronary flow reserve. Patients who subsequently died in one series had abnormal coronary flow reserve on PET scanning at baseline indicating that ischemia may play a role, at least in part, in subsequent mortality.