Chronic Cardiac Adaptation Flashcards Preview

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Flashcards in Chronic Cardiac Adaptation Deck (25)
1

What happens to heart with chronic exercise and pregnancy

physiological hypertrophy

incr myocyte length, incr end diastolic volume, incr volume
no fibrosis
no cardiac dysfunction

2

What causes physiological hypertrophy

chronic exercise
pregnancy

3

What happens to heart with chronic hypertension and aortic valve stenosis

pathological hypertrophy

incr myocyte width
maybe cardiac dysfunction
decr end diastolic volume

4

what causes pathological hypertrophy

chronic HTN
aortic valve stenosis

5

what happens to heart with MI and DCM

cardiac dilation
INCR MYOCYTE length
extensive fibrosis
myocyte death
advanced cardiac dysfunction

thin walls

6

what was historical view of heart

relatively inert

cardiac enlargement doesn't affect intrinsic contractile properties

7

2 myosin heavy chain isoforms

alpha and beta

8

each myosin has ___ heads and ___ chains

2 heads
2 chains

9

what are the different heterodimers

aa
ab
bb

10

what makes heterodimers of myosin distinct?

distinct ATPase activity

11

which has greater ATPase activity, alpha or beta

ALPHA HAS GREATER ATPase activity

12

alpha and beta myosin heavy chain are ___

encoded by different genes and transcriptionally regulated expression

13

Physiological hypertrophy has ____ ATPase and ___ MHC

increase in ATPase
aa MHC

14

Pathological hypertrophy has ___ ATPase and ___ MHC

Decrease in ATPase
bb MHC

15

Contemporary view of heart

Heart has both phenotypic and genotypic plasticity

16

Phenotypic adaptations may involve both ___ and ___

transcriptional and post-translational modifications

17

Long term effect of HTN

heart ejecting against high pressure so cardiac contraction slower
(less ATPase) --> slower contraction

18

Over time, the effect of HTN

1) HTN

2) develop LVH and increase EDV

3) heart eject against increased afterload (hypertrophy)

4) Frank starling curve shifts down

5) as heart fails, PV curve shifts right so volume incr but SV decr

19

Cellular effects of LVH

1) incr Ca2+ current via L-type Ca2+

2) decr SR pump function by incr PLB/SERCA2 ratio so more cyto Ca2+

3) decr myofilament relax

4) incr cytosolic Ca2+ and new steady state

20

What is Calcineurin?

Phosphatase activated in response to Calcium

long onset so need sustained Ca2+ to activate

21

Effect of calcineurin

1) calcineurin dephos NFAT

2) NFAT translocate to nucleus

3) heart looks like dilated cardiomyopathy

22

Effect of P4H on LVH function

NO EFFECT!!!!

23

Positive feedback in CHF

1) Primary muscle damage
2) Pump dysfunction
3) decr CO
4) neurohumoral activation
5) apoptosis

24

2nd positive feedback loop in CHF

1) Primary muscle damage
2) Pump dysfunction
3) decr CO
4) LVH
5) ventricular remodeling

25

Effects of CHF

edema
tachycardia
congestion