Formulas

Question 1

CO (2 formulas)

Answer 1

CO = SV x HR
CO = VO2 / AVO2D

Question 2

Cardiac index

Answer 2

CO/BSA

Question 3

LVEF

Answer 3

SV/LV-EDV

Question 4

Flow rate (volumetric flow)

Answer 4

Flow velocity x CSA

NB: flow in a continuous chamber is constant, so vel1 x CSA1 = vel2 x CSA2

Question 5

compliance

Answer 5

change in volume / change in pressure

Question 6

Bernoulli

Answer 6

P is inversely proportional to vel^2 (P + v^2 = constant, aka P ~ 1/v^2): high velocity = low P, small changes in vel make big P changes

Question 7

LaPlace

Answer 7

Wall stress (Tw) = P x radius / h (wall thickness): the bigger the chamber, the more F is needed to generate a given P (aortic aneurysms)

Question 8

Poiseuille

Answer 8

Q (rate of flow) = (change in P x rad^4)/ (viscosity x length of tube) : small change in radius has big effect on flow (incr rad = incr flow)

Question 9

Ohm’s law in terms of pressure and flow

Answer 9

V = IR –> P = Q (flow rate) x R (resistance)

Q (flow rate) = change in P/change in R

Question 10

SVR

Answer 10

SVR = MAP - RAP / CO

Question 11

PVR

Answer 11

PVR = PAP - LAP / CO (should be ~1/3 of TPR)

Question 12

TPR

Answer 12

TPR = PAP / CO

Question 13

O2 capacity

Answer 13

g Hb x 1.34 (max amt of oxygen that the blood could carry - dependent on amt of Hb)

Question 14

O2 content

Answer 14

O2 capacity x %sat = (g Hb x 1.34) x %sat (amount of O2 the blood is actually carrying)

Question 15

RBBB morphology

Answer 15

RSR’ in V1 (positive R’ is tallest) & big, wide downward S sweep in V6

Question 16

LBBB morphology

Answer 16

big, wide negative S in V1 & big, wide upward R in V6

Question 17

direction of V1

Answer 17

L to R (and anterior)

Question 18

direction of V6

Answer 18

R to L

Question 19

relation of systemic/mean arterial pressure (SAP) to CO and SVR

Answer 19

SAP = SVR x CO