Cardiac test stuff to memorize Flashcards
Three meds that increase Calcium by preventing Ca brakdown?
PDE inhibitors
glucagon
digitalis
drugs/states that slow ca channels and decrease Ca entry into cardiac cells?
acidosis
volatiles
N2O
SNS innervation of the heart?
T1-T4 and stellate ganglion
what makes up SV?
preload after load and contractility
75% of blood volume resides in?
veins
Bainbridge reflex?
increased volume in RA causes increased HR by 10-20%
what establishes length of myocyte immediately before isovolumetric contraction?
preload
what is the law for wall tension? what is the formula?
Law of laplace
T(wall tension)=P (pressure) x (radius)
formula for SVR
SVR=80 (MAP-CVP/CO)
normal SVR range?
900-1500
normal PVR range?
50-150
PNS innervates what in the heart?
atria and conduction tissue
what aspects of chemical enviroment affect contractility? what is the most important?
Ca, Mg, O2, pH
Ca is the most important
normal EF?
68%
Left main coronary artery divides into what?
LAD and circumflex
LAD has what branches? what do they supply?
1-3 diagonals anterolateral LV
septal branches: septum, bundle branches, purkinje fibers
LAD supplies 45-55% of the LV, runs in inter-ventricular groove
Circumflex supplies what and has what branches that supply what?
1-3 obtuse marginals: lateral wall of LV and part of SA node
in 15% of people gives rise of PDA
runs in the AV groove
what does RCA supply and branch into?
divides into acute marginal branches
supplies RV, right anterior wall, SA node
gives rise to PDA in 85% of people
SA node in 60% of people
normal CPP?
60-80
CPP formula? autoregulated in what range?
CPP = AoDBP-LVEDP
50-150
normal O2 content in the blood?
20ml/100ml
primary determinant of O2 level in the blood?
Hgb level
MVO2 formula?
MVO2=CBF-(CaO2-Cvo2)
3 main determinants of myocardial oxygen consumption? What is most important?
HR, contractility, and wall stress
HR is the most important one. Doubling HR more than doubles O2 demand, so non linear relationship
how to calculate wall stress?
Wall stress (tension) = (pressure x radius) / (2 x wall thickness)
MAP correlates with, ______ not ______
MVO2, not SBP
doubling pressure in the heart _____ O2 demand
doubles
increased pre load increases MVO2 to a _____ ______
lesser extent
formula for CBP?
CPP/CVR
normal CBF?
225-250ml/min
What will increase CVR?
increased O2
decreased CO2
decreased H+
increased alpha 1
increased cholinergic tone
increased vasopression
antiogensin
thromboxane
what causes decreased CVR?
decreased O2
increased CO2
increased H+
increased Beta 1 tone
prostacyclin
NO
endothelial derived hyperpolarizing factor
prostaglandin I2
what does alpha 1 stimulation do?
constriction, mainly epicardial arteries
what does beta 1 stimulation do?
dilation, mainly intramuscular arteries
how do benzos affect hemodynamics?
limited hemodynamic effects
why do bad hearts love opioids?
decreased O2 demand without decreased contractility
what opiod will increase HR and contractility?
meperidine (Demerol)
CV effects of opioids?
decrease SVR (worse with benozs)
decrease Preload (worse with histamine release)
decreased SNS stimulation
what are alpha 2 agonists used for in cardiac surgery?
decrease HR and BP, used intra-op and post op to decrease opioid requirement, and therefore less resp depression
Volatiles effects on on hemdynamics?
all decrease contractility and all decrease afterload Sevo<iso and des
minimal chagnes on preload
HR increased with Des>iso>sevo
Nitrous Oxide effects on hemodynamics?
decreased contractility, increased PVR
what to watch for with Succ?
bradycardia, espeically with repeat doses
how does pancuronium affect hemodynamics?
increase HR by 20%, attenuated by high dose narcotic admin
how do vec and roc affect hemodynamics?
minimal CV effects, possible bradycardia
cisatricurium effects on hemodynamics?
no effect
how soon do you see ST changes?
1-2min after ischemia ocurs
where do you look for ST chagnes?
0.08 seconds after j point
which leads are the most sensitive for ischemia? what percentage of ischemia do they detect?
2,3, aVF and especially V5
detect 90% of ischemia
new onset V wave on PCWP indicates what?
papillary muscle dysfunction
downstroke on a-line represents what?
PVR
