Definitions

Question 1

Ejection Fraction

Answer 1

ratio of vol of blood ejected from ventricle per beat (SV) to vol of blood in ventricle at end of diastole, load-dependent parameter

Question 2

Chronotrophy

Answer 2

Changes in HR

Question 3

Lusitrophy

Answer 3

myocardial relaxation; energy-consuming process linked to reuptake of Ca

SNS stimulation: +lusitrophic effect

Ventricular relaxation impaired by hypoxia, acidosis, cardiac dz (LV hypertrophy, ischemia)

Question 4

Bathmotrophy

Answer 4

changes to excitability of heart m

Question 5

Dromotrophy

Answer 5

conduction velocity through AVN

Question 6

Ventricular Systolic Function

Answer 6

principal determinant of SV

myocardial contractility, relaxation, preload, afterload

Question 7

Ventricular Diastolic Function

Answer 7

coronary perfusion, myocardial relaxation

myocardial compliance, filling pressures, mechanical rhythm/function, SNS activity, venoconstriction, venous return

Question 8

Stroke Volume

Answer 8

vol of blood ejected during one ventricular ctx

Consists of preload, after load, contractility

=EDV-ESV

Question 9

Preload

Answer 9

venous return during diastole preloading ventricle before ctx/eject

Question 10

Afterload

Answer 10

resistance against systolic ejection that ventricle must overcome IOT eject blood

Question 11

Frank Starling

Answer 11

more heart muscle is stretched during filling, greater the force of ctx, greater quantity of blood pumped into the area

Question 12

SAP

Answer 12

peak pressure maintained in artery or arteriole during one cardiac cycle

Determined by SV, velocity of LV ejec, arterial resistance, blood viscosity

Question 13

DAP

Answer 13

lowest arterial pressure measure during cycle

Affected by blood viscosity, arterial compliance, cardiac cycle length

Question 14

Isovolumetric contraction

Answer 14

rapid increase in ventricular pressure while both AV, semilunar valves closed so ventricular vol remains constant, right arm of PV loop

Question 15

Isovolumetric relaxation

Answer 15

period btw closure of semilunar valves, opening of AV valves
o Beginning of ventricular diastole
o Rapid decrease in ventricular pressure, no change in ventricular vol

Question 16

Isotonic Contraction

Answer 16

period where semilumar valves open, minimal changes in ventricular pressure but ventricular vol decreases

Question 17

Frank Starling Curve

Answer 17

SV vs EDP: afterload dependent measure of inotropy

Increased inotrophy shifts curve up, L
Decreased shifts curve down, R

Question 18

QT Interval

Answer 18

duration of ventricular AP, ventricular depolarization, repolarization

Question 19

PR Interval

Answer 19

onset of P wave to start of QRS complex, reflects conduction through AV node

Question 20

RR Interval

Answer 20

duration btw each cardiac cycle

Question 21

PR/PQ Interval

Answer 21

time for atria to contract prior to ventricular filling, atrial kick

Question 22

ST Segment

Answer 22

interval beginning immediately after S wave of QRS (J point) and preceding T wave

Question 23

Unstressed Volume

Answer 23

certain vol required to fill vascular bed to point where presence exerts force on vessel walls

Question 24

Stressed Volume

Answer 24

any vol above unstressed volume’s exertion of pressure, exerts increasing depress of pressure on venous vascular bed

Question 25

Ohm’s Law

Answer 25

current inflow in electrical circuit = electromotive force/voltage or resistance to flow
o I (current) = E (voltage)/R
o Flow of fluids through non-distensible tube: flow = driving pressure/resistance to flow (Q=P/R)

Question 26

Fahraeus-Linquist Effect

Answer 26

centralization of RBCs, decreased RBC #s at vessel wall (plasma skimming)

Small vessels