Publicação: Influência da pós-carga sobre a taxa de variação da tensão desenvolvida (dT/dt). Estudo em músculo cardíaco isolado.
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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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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
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Português
Como citar
Arquivos brasileiros de cardiologia, v. 65, n. 5, p. 417-421, 1995.