Chronic Cardiac Adaptation Flashcards Preview

CV wk1 and wk2 > Chronic Cardiac Adaptation > Flashcards

Flashcards in Chronic Cardiac Adaptation Deck (13):
1

Cardiac dilation

Myocyte length increase >> myocyte width increase
Extensive fibrosis
Myocyte death
Advanced cardiac dysfunction

2

Pathological hypertrophy

Myocyte length increase < myocyte width increase
Fibrosis
Maybe cardiac dysfunction

3

Physiologic hypertrophy

Myocyte length increase > myocyte width increase
No fibrosis
No cardiac dysfunction

4

What types of MHC exist? What do they form and how do they differ?

There are alpha and beta isoforms
Form heterodimers (aa, ab, and bb)
Have distinct ATPase activity (and some other functional properties)

5

Biochemical property of pathological hypertrophy

Decrease in ATPase and increase in bb MHC

6

Biochemical property of physiological hypertrophy

Increase in ATPase activity and aa MHC

7

The heart has not only _____ plasticity but also _____ plasticity

phenotypic, genetic

8

The functional adaptations of the heart are generally ____ but can result in ventricular dysfunction over time

adaptive

9

LVH --> CHF phenotype

Heart becomes more stiff, concentrically hypertrophied = pathologic hypertrophy

LVH:
At same EDV, less CO because heart is ejecting against increased afterload

CHF:
As heart fails, PV curve shifts right (dilated cardiomyopathy)

10

Cellular mechanisms of LVH

1. Increase in Ca current via L-type Ca channel
2. Reduced SR pump fxn via increased PLB/SERCA2 ratio
3. Impaired myofilament relaxation
4. Altered (increased) cytosolic calcium and new steady-state

11

____ gene transfer is sufficient to correct mechanical defects in cadiocytes from animals with HF

SERCA2

12

Calcineurin & NFAT to demonstrate that genes really can lead to LVH or other remodeling

Calcineurin dephospho NFAT
NFAT translocates into nucleus & influences gene transcrption ofcardiac growth and remodeling genes = some master regulatory switches.

13

Explain the animal testing of LV function following an acute insult

Give animal heart attack
EF drops, heart function fails...
Over time things got worse despite attempts to use P4H

Why? Series of positive feedback loops. If you don't do something to interrupt them, you will see progressive decline in cardiac fxn. Current therapy is trying to interrupt.