Effects of vasopressin on hrt rate?

[chiuli]

I know that if you give vasopressin to someone with lets say septic shock, it will increase their MAP. But what about their hrt rate? To me it seems like the vasoconstriction increases perfusion but it unfortunately would lead to less blood blow to the heart and lowers the heart rate. What do you think?

Im confused with the decreased filling time concept here

[MunoRN, RN]

Vasopressin is not considered an inotrope and therefore should have no direct effect on HR or contractility, as opposed to other pressors like Levo or Dopamine. That doesn't mean that it's effect on PVR won't indirectly affect HR through the body's normal feedback mechanisms.

[ukstudent]

I know that if you give vasopressin to someone with lets say septic shock, it will increase their MAP. But what about their hrt rate? To me it seems like the vasoconstriction increases perfusion but it unfortunately would lead to less blood blow to the heart and lowers the heart rate. What do you think?

Im confused with the decreased filling time concept here

I don't understand your thinking. Vassopressin is a pure alpha receptor drug, it has no chronotropic or inotropic properties. Vasocostrictors do just that, they constrict the blood flow leading to decreased peripheral perfusion, pushing the blood back to the core. This then leads to an increase in blood flow to the heart and other core organs. Why do you think it would lead to less blood flow? Why do you think that less blood flow would lower the heart rate rather than increase it? With decreased blood flow the heart speeds up in order to try and keep the stroke volume stable.

[RNextraordinare]

In theory it should increase your afterload and hopefully through normal feedback mechanisms cause a decrease in HR. With Neosynphrine it is pure alpha and should decrease heartrate by increasing afterload where as norepinpehrine will increase HR and SVR