The apelin-APJ system is a recently discover hormone system that has several important
actions in the cardiovascular system. Apelin causes the heart pump with more force and also
causes blood vessels to relax. Studies to date show that people with reduced pumping function
of the heart have lower levels of apelin in the bloodstream compared to people with normal
heart function. We have previously given apelin to healthy volunteers and people with reduced
pumping function and this increases the heart's contraction. However, this has only been
assessed over a short time period, around fifteen minutes, and we now want to know if this
effect is seen over a longer period.