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https://www.arca.fiocruz.br/handle/icict/14614
PATHOLOGY OF COMPLETE ATRIOVENTRICULAR BLOCK IN CHRONIC CHAGAS’ MYOCARDITIS
Affilliation
Fundação Gonçalo Moniz, Instituto de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil
Fundação Gonçalo Moniz, Instituto de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil
Universidade Federal da Bahia. Salvador, BA, Brasil
Fundação Gonçalo Moniz, Instituto de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil
Universidade Federal da Bahia. Salvador, BA, Brasil
Abstract
Sclero-atrophy, fibrosis, vascular ectasia, phlebosclerosis and mild non-specific
chronic inflammatory changes were observed in variable location and proportion
involving the atrioventricular conducting tissue o f the heart in five human cases o f
chronic Chagas’ myocarditis associated with complete atrioventricular block. One case
presented complete destruction o f the A- V conduction system. In three cases the lesions
were disseminated all along the conducting tissue but did not cause anywhere a complete
disruption in the continuity o f the system. The distal portion o f the bundle branches were
the most damaged sector o f the system, exceptfor the fasciculi o f the posterior division o f
the left bundle branch which were relatively preserved. One case exhibited bilateral
sclero-atrophy o f the bundle branches as the main change; and another showed early and
mild fibrocalcific damage o f the penetrating portion o f the His bundle. The A -V node
appeared as the least involved part o f the conducting system in the cases studied.
Demonstration o f the lesions in this series o f cases seems important because: a) it
reveals that complete atrioventriculr block in chronic Chagas’ disease results from
disseminated lesions and not from fo ca l disruptive change as has been commonly
observed in cases o f other etiologies; b) it shows that chronic inflammation can produce
at the end variable and widespread vascular, degenerative andfibrotic alterations within
the conducting tissue o f the heart, which may lead to its total destruction.
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