Step I CV physio question...

[StringBean]

I may just be ALOT tired 😴 but I can't seem to figure out exactly why acidosis, hypercapnea & hypoxia cause a decrease in cardiac contractility. Anyone out there know? Thanks in advance!

~Bean

 

[GobindSingh]

just my thinking on the matter:

co2 leads to increased h+, so hypercapnia and acidosis are for all intents and purposes the same thing, acidosis leads to increased intracellular buffering so h+ goes into the cell, k+ leaves, if alot of k+ leaves, you have depolarizing blockade of myocardium and the heart can't beat as hard or as fast...as for hypoxia, the heart is dependent on fatty acids for fuel not glucose, so the kreb's cycle is mandatory, if there is no o2, then you can't oxidize fatty acids and don't have atp for cross-bridge recycling and can't contract...

i may be wrong about these mechs but i think they are accurate....