Afterload-induced diastolic dysfunction contributes to high filling pressures in experimental heart failure with preserved ejection fraction

• Tipo: Artigo em Revista Científica Internacional
• Data: 2015

Autores

Leite, S (Autor) FMUP; Rodrigues, S (Autor) Outra; Tavares Silva, M (Autor) FMUP; Oliveira Pinto, J (Autor) FMUP; Alaa, M (Autor) Outra; Abdellatif, M (Autor) Outra; Fontoura, D (Autor) Outra; Falcao Pires, I (Autor) FMUP; Gillebert, TC (Autor) Outra; Leite-Moreira AF (Autor) FMUP; Andre P Lourenco (Autor) FMUP

Revista

Título: American Journal of Physiology - Heart and Circulatory Physiology

Vol. 309

ISSN: 0363-6135

Editora: American Physiological Society

Indexação

ISI Web of Knowledge - 30 Citações

Scopus - 31 Citações

Outras Informações

ID Authenticus: P-00G-WDY

DOI: 10.1152/ajpheart.00397.2015

Abstract (EN): Myocardial stiffness and upward-shifted end-diastolic pressure-volume (P-V) relationship (EDPVR) are the key to high filling pressures in heart failure with preserved ejection fraction (HFpEF). Nevertheless, many patients may remain asymptomatic unless hemodynamic stress is imposed on the myocardium. Whether delayed relaxation induced by pressure challenge may contribute to high end-diastolic pressure (EDP) remains unsettled. Our aim was to assess the effect of suddenly imposed isovolumic afterload on relaxation and EDP, exploiting a highly controlled P-V experimental evaluation setup in the ZSF1 obese rat (ZSF1 Ob) model of HFpEF. Twenty-week-old ZSF1 Ob (n = 12), healthy Wistar-Kyoto rats (WKY, n = 11), and hypertensive ZSF1 lean control rats (ZSF1 Ln, n = 10) underwent open-thorax left ventricular (LV) P-V hemodynamic evaluation under anesthesia with sevoflurane. EDPVR was obtained by inferior vena cava occlusions to assess LV ED chamber stiffness constant beta, and single-beat isovolumic afterload acquisitions were obtained by swift occlusions of the ascending aorta. ZSF1 Ob showed increased ED stiffness, delayed relaxation, as assessed by time constant of isovolumic relaxation (tau), and elevated EDP with normal ejection fraction. Isovolumic afterload increased EDP without concomitant changes in ED volume or heart rate. In isovolumic beats, relaxation was delayed to the extent that time for complete relaxation as predicted by 3.5 x monoexponentially derived tau (tau(exp)) exceeded effective filling time. EDP elevation correlated with reduced time available to relax, which was the only independent predictor of EDP rise in multiple linear regression. Our results suggest that delayed relaxation during pressure challenge is an important contributor to lung congestion and effort intolerance in HFpEF.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 7