Cardiology 2 Flashcards
how does atrial fibrillation appear on venous pressure wave?
- -A-wave = LOST
- -C-wave = Prominent
split S2 sound physiologic explanation?
-deep breath in; decreases intrathoracic pressure. sucking more blood back to R side of heart; filling R side more than L side. So Right sided pulmonic valve closes later in systolic bc R side has more blood to eject.
what’s a gallop?
all four sounds together
In aortic pressure tracing, what is representative of aortic valve closing? what PHASE does this occur in?
- dicrotic notch
- Phase 4 of cardiac cycle
what heart sound correlates with dicrotic notch?
S2 (it’s when aortic valve closes)
measure CO clinically with what principle?
FICK
what is Fick principle?
can know what the FLOW is, if you measure something being carried along with the FLOW, that can be extracted/added along with the flow.
what things are needed for Fick principle calc?
- entrance to lung blood measure
- sample blood on arterial side
- rate of oxygen useage
what other methods/products can be used to implement the Fick Principle?
-indicator dye
(measure concentration at later point)
-thermodilution
(bolus of saline at different temp, measure temp at later point in circuit to back-calculate the flow)
normal CO?
3-5 L/min
how calculate cardiac index?
normal range?
CI = CO/BSA
2.5-4.2
L/min/m^2
muscle fiber length prior to contraction, which affects SV, is known as?
PRELOAD
-how much blood before
tension against which the muscle must contract?
AFTERLOAD
-how much pressure pushing against
intrinsic property of cardiac muscle that adjusts SV?
Contractility
Which Law addresses PRELOAD?
Laplace
what is the equation for law of laplace?
(for spherical chamber); tension in the wall is equal to pressure times the radius of the chamber; divided by 2*wall thickness
T=Pxr/2h
T = LVEDP*LVEDR/2h
what indicators (however unreliable) have been used to estimate SV?
PCWP and CVP
further from ventricle, more unknown things intervene
other methods?
- PPV (pulse pressure variation)
- echo
Preload equals what?
TENSION
what factors affect PRELOAD?
(same as in law)
- pressure
- radius
- wall thickness
Preload INVERSELY proportional to which variable
(2 x) the Wall thickness
End Diastolic filling pressure affected by
- how much blood came back to fill
- compliance of heart chamber
- venous compliance
- atrial contraction
end diastolic radius affected by what issue?
-dilated cardiomyopathy (decompensated)
tension developed in ventricle during PEAK systolic contraction
AFTERLOAD (what ventricle pushes against)