RESUMO
OBJECTIVE: To assess the arrangement of myocardial bridges. DESIGN: A necropsy study of 90 consecutive hearts (56 male, 34 female). RESULTS: Myocardial bridges, either single or multiple, were seen in 50 (55.6%) of the 90 hearts. The left anterior descending artery was the most commonly affected artery. Thirty five of the 50 hearts which contained in total 41 muscle bridges were dissected further with a magnifying glass. Two different types of muscle bridges could be identified. Thirty one of these 41 myocardial bridges were superficial, crossing the artery transversely towards the apex of the heart at an acute angle or perpendicularly. The remaining 10 myocardial bridges crossed the left anterior descending coronary artery and surrounded it by a muscle bundle that arose from the right ventricular apical trabeculae and crossed the artery transversely, obliquely, or helically before terminating in the interventricular septum. CONCLUSIONS: The superficial type of myocardial bridge does not seem to constrict the artery during systole but the deep muscle bridges, by virtue of their relation with the left anterior descending coronary artery, could twist the vessel and thus compromise its diastolic flow. This may result in ischaemia.
Assuntos
Vasos Coronários/anatomia & histologia , Coração/anatomia & histologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Envelhecimento , Criança , Pré-Escolar , Doença das Coronárias/patologia , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Miocárdio/patologia , Caracteres SexuaisRESUMO
1. It has been demonstrated that chronotropic responses differ in healthy elderly subjects compared to those in younger normal adults. To evaluate the involvement of the autonomic nervous system, we determined the number of neurons in right atrial strips from six elderly individuals (aged 77 +/- 3.4 years) five of whom had died as the result of extracardiac causes, and from younger adult controls (aged 44.0 +/- 6.0 years) who had died in traffic accidents. 2. There was a significant reduction in the number of neurons of the group of hearts from the elderly (3587 +/- 445, mean +/- SEM) compared with the control group (6412 +/- 377) of five hearts from younger adults (P less than 0.001). 3. It is suggested that this decrease in the number of neurons contributes to the reduced chronotropic responses in the aged. The mechanisms responsible for the neuronal depopulation was not determined.
Assuntos
Átrios do Coração/inervação , Neurônios/citologia , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Contagem de Células , Feminino , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
It has been demonstrated that chronotropic responses differ in healthy elderly subjects compared to those in younger normal adults. To evaluate the involvement of the autonomic nervous system, we determined the number of neurons in right atrial strips from six elderly individuals (aged 77 + or - 3.4 years) five of whom had died as the result of extracardiac causes, and from younger adult controls (aged 44.0 + or - 6.0 years) who had died in traffic accidents. There was a significant reduction in the number of neurons of the group of hearts from the elderly (3587 + or - 445, mean + or - SEM) compared with the control group (6412 + or - 377) of five hearts from younger adults (P<0.001). It is suggested that this decrease in the number of neurons contributes to the reduced chronotropic responses in the aged. The mechanisms responsible for the neuronal depopulation was not determined
Assuntos
Adulto , Pessoa de Meia-Idade , Humanos , Masculino , Feminino , Envelhecimento/fisiologia , Átrios do Coração/citologia , Neurônios/análise , Idoso de 80 Anos ou mais , Contagem de Células , Frequência CardíacaRESUMO
O autor apresenta a definicao e classificacao de cardiomiopatias, destacando a diferenciacao com base em elementos de ordem clinica, hemodinamica e patologica. Tambem chama a atencao para a importancia do reconhecimento precoce dessas entidades clinicas, o que pode ser feito mediante a analise de tecido endomiocardico recolhido por biopsia cardiaca.O autor ocupa-se particularmente da cardiomiopatia hipertrofica. Os mais recentes conhecimentos sobre o tipo restritivo de cardiomiopatia (endomiocardiofibrose) sao tratados em outro artigo deste numero especial da revista
Assuntos
Humanos , CardiomiopatiasRESUMO
Sem considerar areas geograficas, a endomiocardiofibrose (EMF) e a princial causa da patologia da doenca endomiocardica eosinofilica e da endomiocardiofibrose tropical mostram que se trata de um mesmo processo, de aparente patogenese. O desenvolvimento de fibrose no endocardio parece associado com produtos de celulas eosinofilicas, havendo uma associacao positiva entre cardiopatia e o numero de eosinofilos degranulados, no sangue e nos tecidos.Trabalhos experientais em celulas isoladas de coracao de ratos mostram a toxicidade para essas celulas produzidas por elementos de secrecao dos eosinofilos.Esses produtos, alem de causarem alteracoes morfologicas nas membranas, inibem as principais enzimas oxidativas da cadeia respiratoria das mitocondrias. Esses resultados devem estimular novos estudos em doencas com hipereosinofilia em areas tropicais, a fim de consubstanciar a hipotese de que os eosinofilos sao tambem responsaveis pela endomiocardiofibrose tropical