Influência da pós-carga sobre a taxa de variação da tensão desenvolvida (dT/dt). Estudo em músculo cardíaco isolado.

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Data

1995-11-01

Autores

Okoshi, M. P.
Ferreira Tucci, P. J.
Okoshi, K.
Padovani, C. R.
Cicogna, A. C.

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Resumo

PURPOSE: To evaluate the effects of afterload on peak rate of tension rise (dT/dt) in the isolated muscle. METHODS: Left ventricular papillary muscles from Wistar rats were studied in isometric and isotonic afterloaded contractions. Muscles were analised in Krebs-Henseleit solution with calcium concentration of 2.52mM at 28 degrees C. The resting muscle length (preload) was maintained constant. The peak isometric developed tension (DT) and dT/dt were measured during increases of afterload (25, 50, 75 and 100% from DT). RESULTS: A rise in afterload corresponding to 50, 75 and 100% of DT, did not cause an increase in dT/dt values (p > 0.05). The dT/dt value decreased (p < 0.05) when afterload was changed from 75% to 25% of DT. CONCLUSION: The data suggest that an increase in the afterload from 50% of the DT did not promote changes in the dT/dt.

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Palavras-chave

animal, heart contraction, heart output, heart papillary muscle, male, muscle isometric contraction, physiology, rat, Wistar rat, Animals, Cardiac Output, Isometric Contraction, Male, Myocardial Contraction, Papillary Muscles, Rats, Rats, Wistar

Como citar

Arquivos brasileiros de cardiologia, v. 65, n. 5, p. 417-421, 1995.