Pump

Question 1

typical sarcomere length

Answer 1

1.8-2.2 microns

Question 2

2 most important factors for controlling force generation?

Answer 2

Ca [ ] (inc w/ inc)
length of muscle cell at initation of excitation contraction coupling aka:preload (inc w/ inc
(3rd factor = afterload, dec w/ inc)

Question 3

bowditch effect (aka: treppe)

Answer 3

as HR inc -> force development inc

**effect is optimal during certain range of HR *150-180 stim/min

Question 4

endocardial fibers are a ___handed helix

epicardial fibers are a ____handed helix

Answer 4

endocardial: R handed
epicardial: L handed

Question 5

when the heart muscle contracts it___?

Answer 5

twists (apex rotates counterclock, base rotates counter)
shortens
moves inward radially
translates w/in space

Question 6

surface myofibers orientation?

mid wall myofibers orientation?

Answer 6

surface: along long axis

mid wall: circumferential

Question 7

clinical measurements of preload (aka: stretch of individual sarcomere?

Answer 7

LV EDP
pulm cap wedge P
non-invasive measurements of filling P
LE EDV
LE end dias dimension

Question 8

clinical measurements of after load?

Answer 8

systolic BP
MAP
SVR
End sys wall stress**
peak sys wall stress

Question 9

measuring cardiac contractility?

Answer 9

force generation
stroke work
end sys P V relation
CO, SV
EJ**

Question 10

how much fluid is in normal pericardium?

Answer 10

15-50 ml

Question 11

pulsus paradoxus

Answer 11

dec of sys BP >10 mmHg during norm inspiration

Question 12

BNP

Answer 12

produced by ventricle when dias P and wall stress are increased
high levels in HF pts, esp if related dyspnea
low levels rule out HF except if obese (should double # to correct), mitral stenosis, pericard dz, or flash pulm edema

Question 13

non heart failure causes for elev BNP?

Answer 13

acute pulm edema
ACS
pulm HTN
COPD
pneumonia
renal failure

Question 14

what are the 3 underlying processes that contribute to HF progression and sxs?

Answer 14

1. blunted physiological responses to altered load
2. neurohormonal act
3. adverse remodeling

Question 15

what causes arterial stiffening? (7)

Answer 15

age
HTN
DM
smoking
hyperchol
ssedentary
abdom obesity