Light micrograph section through human heart muscle showing brown atrophy of the myocardium. This refers to atrophy of the heart muscle (or myocardium) commonly found in the elderly. It is described as brown because the fibres become pigmented by intracellular deposits, mostly around the cell nucleus of lipofuscin, a type of lipochrome granule. It has no known effect on function and is described as a normal part of the ageing process.