EKG--Nordgren Flashcards
Feature of echo that allows measurement of flow
doppler
determines flow speed and direction by determining if blood is moving toward or away form probe
Importance of end systolic volume-pressure relationship
measurement of cardiac contractility
What increases cardiac contractility and therefore the end systolic pressure-volume relationship?
vasoconstrictors
What decreases cardiac contractility and therefore the end systolic pressure-volume relationship?
heart disease
Fick principle
calculates amount of substance being added/removed from circulation at capillary bed
Q= Xtc/(Xa-Xv)
Cardiac index
corrects CO for patient size
uses surface are, not mass
use chart, mark lines where they cross
A large EKG box is how much time?
0.2 sec
Einthoven’s triangle
EKG measures difference between these leads
What determines how big the spike is on the EKG from any given heart activity?
net dipole in direction of detection
larger magnitude and correct direction
Positive inflection on EKG means
charge traveling to like electrode
Foot electrode charge
positive
Left wrist electrode charge
+ and -
Right wrist electrode charge
-
The last ventricular cells to depolarize…
are the first to repolarize
this explains why R wave and T wave are positive inflections
Mean electrical axis
orientation of cardiac dipole during most intense phase
