Ejection time

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Can someone please explain ejection time! Why do nitrates cause decreased ejection time and why does Beta blockers increase it?
Nitrates: ↓venous return → ↓EDV → ↓SV → ↓ejection time
Beta blockers: ↑vascular resistance (ß2 vascular receptors) → ↑afterload → ↑ejection time
 
Nitrates: ↓venous return → ↓EDV → ↓SV → ↓ejection time
Beta blockers: ↑vascular resistance (ß2 vascular receptors) → ↑afterload → ↑ejection time

I thought BB decrease afterload by inhibiting B1 on Juxaglomerular appratus from releasing renin (no AT2= no vasoconstriction).
 
I thought BB decrease afterload by inhibiting B1 on Juxaglomerular appratus from releasing renin (no AT2= no vasoconstriction).
That's a short term phenomenon. AT2 levels are back to normal within a few weeks. (Then again, AT2 levels go back to reference range even with ACE-I in the same span of time, so who really knows.)

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Nitrates: ↓venous return → ↓EDV → ↓SV → ↓ejection time
Beta blockers: ↑vascular resistance (ß2 vascular receptors) → ↑afterload → ↑ejection time


↑vascular resistance (ß2 vascular receptors) is only in the beginning right?
"Cardiodepression initially evokes a proportional rise in vascular resistance"??? But over the long run, it should lower blood pressure by lowering vascular resistance?
 
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