<prompt> The pathognomonic feature of rheumatic hea disease isAschoff noduleCaterpillar cellMcCallum plaquesFibrinous pericarditis  <response>: During acute RF, distinctive lesions occur in the hea, called Aschoff bodies, consisting of foci of T lymphocytes, occasional plasma cells, and plump activated macrophages called Anitschkow cells pathognomonic for RF. These macrophages have abundant cytoplasm and central round-to-ovoid nuclei occasionally binucleate in which the chromatin condenses into a central, slender, wavy ribbon hence the designation caterpillar cells. 