Chronic Cardiac Adaptation

Question 1

The response of the heart to ACUTE hemodynamic and adrenergic stimuli

Answer 1

Altered P/V relationships
Altered inotropy
Altered chronotropy

Question 2

______ Myosin heavy chains (MHC) isoforms are found in the heart and fx

Answer 2

α and β

*The heterodimers (αα, αβ and ββ) have distinct ATPase activity

Question 3

Decrease in ATPase and increase ββ MHC

Answer 3

Pathologic Hypertrophy  
(fibrosis/dysfunction)

Question 4

Increase in ATPase and in αα MHC

Answer 4

Physiologic hypertrophy (exercise/prego)

Question 5

LVH : Cellular mechanisms

Answer 5

Likely increase in Ca current via L-type Ca channel

Reduced SR pump fxn
(↑ PLB/SERCA2 ratio)

Impaired myofilament relaxation

Altered (increased) cytosolic ca/new steady-state