Failing Left Ventricles Have an Enhanced Post-Stimulation Potentiation Despite Their Impaired Force Frequency Relationship
نویسندگان
چکیده
منابع مشابه
Effect of inotropic stimulation on the negative force-frequency relationship in the failing human heart.
BACKGROUND In severe human heart failure, an increase in frequency of stimulation is accompanied by a reduced force of contraction in vivo and in vitro. The present study was aimed to investigate whether inotropic stimulation influences the inverse force-frequency relationship in failing human myocardium. METHODS AND RESULTS The effects of the cAMP-independent positive inotropic agents ouabai...
متن کاملForce-Frequency Relationship in the Failing Human Heart
a reduced force of contraction in vivo and in vitro. The present study was aimed to investigate whether inotropic stimulation influences the inverse force-frequency relationship in failing human myocardium. Methods and Results. The effects of the cAMP-independent positive inotropic agents ouabain (0.01 ,imol/L) and BDF 9148 (0.1 ,umol/L) as well as the 3-adrenoceptor agonist isoprenaline (0.01 ...
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Repetitive activation of a skeletal muscle results in potentiation of the twitch contractile response. Incompletely fused tetanic contractions similar to those evoked by voluntary activation may also be potentiated by prior activity. We aimed to investigate the role of stimulation frequency on the enhancement of unfused isometric contractions in rat medial gastrocnemius muscles in situ. Muscles...
متن کاملMechanical alternans and restitution in failing SHHF rat left ventricles.
We examined mechanical alternans and electromechanical restitution in normal and failing rat hearts. Alternans occurred at 5 Hz in failing versus 9 Hz in control hearts and was reversed by 300 nM isoproterenol, 6 mM extracellular Ca(2+), 300 nM -BAY K 8644, or 50 nM ryanodine. Restitution curves comprised phase I, which was completed before relaxation of the steady-state beat, and phase II, whi...
متن کاملIntramuscular Contributions to Low-Frequency Force Potentiation Induced by a High-Frequency Conditioning Stimulation
Electrically-evoked low-frequency (submaximal) force is increased immediately following high-frequency stimulation in human skeletal muscle. Although central mechanisms have been suggested to be the major cause of this low-frequency force potentiation, intramuscular factors might contribute. Thus, we hypothesized that two intramuscular Ca2+-dependent mechanisms can contribute to the low-frequen...
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ژورنال
عنوان ژورنال: International Heart Journal
سال: 2016
ISSN: 1349-2365,1349-3299
DOI: 10.1536/ihj.15-374