Significance of ACTH and acute MI?

[shocker]

---

Members do not see this ad.

I am stuck. Why are ACTH and catecholamine levels elevated in the morning and how does that relate to more heart attacks in the A.M.?

My Biochem book claims this stuff and I have to present a case tomorrow.

Thank you in advance.

 

[omarsaleh66]

I am stuck. Why are ACTH and catecholamine levels elevated in the morning and how does that relate to more heart attacks in the A.M.?

My Biochem book claims this stuff and I have to present a case tomorrow.

Thank you in advance.

ACTH levels are high in the AM becuase there is a diurnal pattern where u will get high cortisol levels peaking at about 8-9AM and settling down by 12 PM. Since ACTH is high in the AM, u will get high levels of cortisol and since the adrenal gland is being hit by ACTH, u might get some high catecholamines because of this too (My guess on this part).

High catecholamines are bad news for a weak heart. These will hit the Beta one receptors of the heart and cause increased contraction that is bad news for a weak heart. Furthermore, catecholamine will hit the alpha one receptors and vasoconstrict the vessels so that will increase your total peripheral resistance. That means an increased afterload for the heart to pump against. ALL that pressure on the heart, u get an Myocardial Infarction (Heart attack).

Sorry if I over-simplified it, maybe u are first year and u havent learned all this yet?
gluck

Omar

 

[johnstoner]

more importantly...people with myocardial ischemia are prone to have areas of myocardium that are "supersensitive" to catecholamines...this is called denervation supersensitivity. This will cause arrythmias and lead to death. That is why you want to give beta blockers as part of your therapy...