03b: EKG and CO Flashcards
ECG records changes in (X) versus (Y).
X = electrical potential Y = time
Upward deflection of ECG is indicative of (X) at (positive/negative) electrode.
X = positivity at positive electrode OR negativity at negative electrode
The same size dipole can generate smaller or larger signal, depending on (X).
X = orientation with lead axis
Lead I positive and negative electrodes.
Neg: RA
Postiive: LA
Lead II positive and negative electrodes.
Neg: RA
Positive: LL
Lead III positive and negative electrodes.
Neg: LA
Positive: LL
(X) event in cardiac cycle accounts for most of PR interval in ECG.
X = AV nodal delay
T wave: (upward/downward) deflection of (de/re)-polarization is due to (endo/epi)cardial fibers repolarizing before (endo/epi)cardial fibers.
Upward;
Repolarization (ventricles);
Epicardial;
Endocardial
Resultant vector of T wave points in which direction(s)? This is the same orientation as which other ECG deflection?
Down and to the left;
R-wave
T wave lasts (shorter/longer) than QRS complex. This is because (depolarization/repolarization) spreads at slower velocity.
Longer;
Repolarization
Sympathetic stimulation of ventricular muscle increases (X) of contraction.
X = force and velocity
Since (X) of (veins/arteries) is (Y) times greater than (veins/arteries), to achieve the same change in pressure in vessels of same dimensions, (Y) times the volume would have to be added.
X = distensibility;
Veins;
Y = 5-6
Arteries
The volume of blood flowing through
the circulatory system during a given time period.
CO
T/F: CO of LV equals CO of RV.
True
CO units.
L/min
CO is equal to product of (X) and (Y).
X = SV Y = HR
Cardiac index is based on the fact that (X) is (directly/indirectly) proportional to (Y).
X = CO
Directly;
Y = body surface area
The Fick principle is a (direct/indirect) method to measure (X). What’s the equation?
Indirect;
X = CO
CO = (O2 uptake by lung)/([O2]a-[O2]v)
Indicator dilution method is one in which (known/unknown) quantity of (X) is injected into (Y).
Known;
X = dye
Y = blood stream in central vein or heart
Indicator dilution method: where is the detector?
Downstream artery
Increase venous return results in (increase/decrease) in SV. This is due to (increase/decrease) in (X) in (Y) chamber.
Increase;
Increase;
X = P and V
Y = RA
Starling stated the Law of the Heart:
E of contraction is function of length of muscle fiber