Participação do Estado Contrátil e do Relaxamento Miocárdico na Disfunção Ventricular durante a Transição Hipertrofia-Falência Cardíaca

• Autor(a) principal: Cicogna, Antonio Carlos [UNESP]
• Data de Publicação: 1997
• Outros Autores: Robinson, Kathleen G., Conrad, Chester H., Squire, Robin, Okoshi, Marina Politi [UNESP], Bing, Oscar H. L.
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1590/S0066-782X1997001200003; http://hdl.handle.net/11449/65289
• topic: Heart failure; Hypertrophy; Myocardial function; animal; comparative study; forward heart failure; heart contraction; heart left ventricle function; heart left ventricle hypertrophy; heart right ventricle hypertrophy; hypertension; male; pathophysiology; physiology; rat; Wistar Kyoto rat; Animals; Cardiac Output, Low; Hypertension; Hypertrophy, Left Ventricular; Hypertrophy, Right Ventricular; Male; Myocardial Contraction; Rats; Rats, Inbred WKY; Ventricular Dysfunction, Left

Purpose - To investigate the participation of contractile state and relaxation in cardiac muscle dysfunction during the transition from stable hypertrophy to cardiac decompensation in aging spontaneously hypertensive rats (SHR). Methods - isolated left ventricular papillary muscle function was studied in SHR with heart failure (SHR-F), in age-matched SHR without evidence of heart failure (SHR-NF), and in nonhypertensive controls Wistar-Kyoto rats (WKY). Muscles were analised in isometric and isotonic contractions in Krebs-Henseleit solution with calcium concentration of 1.25mM at 28°C. Results - Papillary muscles from SHR-F and SHR-NF demonstrated decreased active tension development and shortening velocity relative to normotensive WKY (p<0.05). SHR-F and SHR-NF did not differ. Compared with SHR-NF and WKY, muscle passive stiffness was increased in the failing SHR (p<0.05 versus WKY and SHR-NF). This parameter did not differ between SHR-NF and WKY (p> 0.05). Conclusion - These data suggest that the progression from stable hypertrophy to heart failure is associated with changes in the passive stiffness and is not related to depression of myocardial contractile function.