Interstitial fibrosis
Pathological deposition of excess collagen between myocardial fibers, leading to cardiac stiffness and dysfunction.
Full Definition
Interstitial fibrosis refers to the abnormal accumulation of collagen and other extracellular matrix proteins in the spaces between individual myocardial fibers (myocytes). This process represents a common endpoint of various cardiac injuries including ischemia, pressure overload, aging, and inflammatory conditions. Unlike replacement fibrosis, which occurs after myocyte death, interstitial fibrosis develops around viable myocytes and can progress to significant cardiac dysfunction. Histologically, it appears as increased pink-staining collagen on routine H&E sections and blue-staining material on trichrome stains. This type of fibrosis impairs cardiac relaxation and can contribute to diastolic dysfunction.
Usage
Usage note: Distinguish from replacement fibrosis, which occurs after myocyte death and forms larger scars.
In Context
- "Extensive interstitial fibrosis was noted throughout the left ventricular myocardium on trichrome staining." — Histopathology report
- "The degree of interstitial fibrosis correlated with the patient's diastolic dysfunction." — Cardiac biopsy evaluation