myocardial fibrosis

When skin is injured, it heals with scar — tough, inelastic tissue that is not the same as the original. Heart muscle does the same: when myocardium is damaged or strained, the body lays down collagen scar. Myocardial fibrosis is this accumulation of stiff fibrous tissue within the heart muscle, replacing or surrounding the contracting cells.

Fibrosis comes in patterns. A dense, regional scar typically follows a heart attack, where dead muscle is replaced by a fixed patch. Diffuse, interstitial fibrosis spreads finely between muscle fibres and accompanies conditions like hypertension, aortic stenosis, diabetes, and many cardiomyopathies. Either way, the heart pays a price: scarred muscle does not contract, stiffens the wall so it fills poorly, and conducts electricity abnormally.

That abnormal conduction is why fibrosis is more than passive scarring — it creates the substrate for re-entrant arrhythmias and raises the risk of dangerous rhythms and sudden death. Cardiac MRI with a contrast agent (late gadolinium enhancement) can map regional scar, and newer techniques estimate diffuse fibrosis. There is great interest in treatments that limit or reverse it, but for now the main strategy is to treat the underlying disease that drives it.