Normal CV Patient Physiology

Question 1

explain the cardiac cycle

Answer 1

1. diastole - filling phase
   – the heart relaxes and blood flows INTO the atria and ventricles
2. systole - pumping phase
   – the heart contracts and pushes blood OUT

Question 2

what happens in normal heart sounds:
– S1 “LUB”
– S2 “DUB”

Answer 2

– closure of AV valves, early ventricular systole, Peak R wave
– closure of SL valves, termination of ventricular systole & starts ventricular diastole, end of T wave

Question 3

what is the correct equation for cardiac output?
a. E = mc2
b. HR + SV
c. [SBP + (DBPx2)]/3
d. EF + HR

Answer 3

B. HR + SV = CO

Question 4

what is cardiac index?
– why is it the most accurate measure of cardiac function?

Answer 4

measurement of how well the heart is functioning
– more individualized than CO and ejection fraction bc it takes the patient’s body size in account

Question 5

what is normal cardiac index?

Answer 5

2.5-4.0 L/min/m2

Question 6

at what cardiac index is a patient likely in cardiogenic shock?

Answer 6

if CI falls below 2.2 L/min/m2

Question 7

what is venous return?
– what are key features?

Answer 7

blood flow back to the heart from the body –> during inhalation, increased abdominal pressure pulls blood back towards the heart
– venous pressure is lower than arterial
distal venous pressure is greater than proximal venous pressure

Question 8

what is the oxyhemoglobin dissociation curve?

Answer 8

relationship between the amount of O2 bound to hemoglobin (RBCs)
– it shows the ability of RBCs to release oxygen to tissues that need it

Question 9

what is the minimum O2 concentration to prevent ischemia in tissue?

Answer 9

SpO2 of 90% = PaO2 of 60mmHg
** think clinically - stop walking patient if SpO2 is < 90%… this is why (muscles don’t have enough O2 providing them)

Question 10

what does a left shift of the oxyhemoglobin dissociation curve mean?

Answer 10

the tissues don’t need more oxygen so hemoglobin holds onto the O2
–> ex: sleeping

Question 11

what does a right shift of the oxyhemoglobin dissociation curve mean?

Answer 11

some tissues need an increase in oxygen so hemoglobin releases O2
–> ex: exercising

Question 12

properties of L AND R shifts of the oxyhemoglobin curve:
– ____ O2 bound to Hgb
– _____ partial pressure of O2
– _____ temp & muscle work
– ____ blood pH

Answer 12

LEFT:
– more
– lower
– lower
– higher (less acidic)

RIGHT:
– less
– naturally happens with exercise
– higher
– lower (more acidic)

Question 13

Normal HR:

Answer 13

60-100 bpm

Question 14

Name the scale rating for the pulse amplitude:
– normal pulse
– absent pulse
– bounding pulse

Answer 14

– 2+
– 0 –> no circulation
– 4+ –> increased stroke volume and ejection fraction

Question 15

when heart rate and stroke volume increase in a normal individual who is exercising, what happens to their cardiac output?

Answer 15

increases –> primary limitation to max O2 consumption during increasing activity

Question 16

an individual’s angina threshold is strongly correlated to ____ and ____
– based on the O2 demand, patient’s WITHOUT pathology will experience angina _____ than someone with pathology

Answer 16

HR and SBP
– later (higher threshold)

Question 17

HR response to exercise in a normal individual:
– _____ linearly as workload & O2 demands increase
– _______ linearly as workload & O2 demands decrease
– remains _____ during steady state

Answer 17

– increases
– decreases
– the same

Question 18

You are working with a 80 year old patient. You first start by performing upper body exercises.
– will this patient have a higher or lower MAX HR than someone who is 15 years old?
– will you expect her to have a higher or lower HR response to the exercise being performed? Why?
– what is a QUICK way to calculate her max HR?
– what is a slower, yet more precise way to calculate her max HR?

Answer 18

– lower - max HR drops with age
– higher - upper body exertion causes higher HR response
– 220-age
– 207 - (0.7xage)

Question 19

normal BP:
normal MAP:
– why would you choose to check MAP over BP?
– how do you calculate MAP?

Answer 19

LESS THAN 120/80
70-110 mmHg
– better indicator of end organ perfusion
– MAP = [SBP + (DBPx2)]/3

Question 20

you should not perform mobility with your patient if they have a MAP < _____

Answer 20

< 65 – not enough O2 for organs

Question 21

what is systolic BP?
what is diastolic BP?

Answer 21

– pressure during ventricular contraction ; force to send blood into distal arteries while aortic valve is open
– pressure during ventricular relaxation while filling ; force to send blood into coronary arteries while valve is closed

Question 22

how is SBP affected during exercise? DBP?
– Pulmonary vascular resistance (PVR)?

Answer 22

– increases linearly w/ increased workload
– only fluctuates ~10mmHg
– drops with activity

Question 23

normal BP responses to exercise:
– rise in ____ is greater than the drop in ____
– upper body exercises cause _____ SBP response
– women have ____ pronounced BP response than men
– _____ body exercise results in greater blood volume redistribution
– redistribution goes away from ___ and ___ towards __

Answer 23

– CO ; PVR
– higher
– less
– lower
– organs & non working muscles ; working muscles

Question 24

what is a normal SPO2 response to exercise?

Answer 24

remains relatively stable

Question 25

your patient is an avid runner and is curious about the distribution of blood flow while she’s running. how do you answer her?

Answer 25

the sympathetic nervous system causes areas of need to vasodilate (open to get extra oxygen) and areas without need vasoconstrict (close when not needing the extra O2)

Question 26

at rest: ____ of CO supplies skeletal muscles
during intense exertion: _____ of CO supplies skeletal muscles

Answer 26

– 15-20%
– 80-85%

Question 27

what is an electrocardiogram (ECG)?
– positive wave?
– negative wave?

Answer 27

visual representation of heart’s electrical activity
– electrical activity moving TOWARDS electrode
– electrical activity moving AWAY from electrode

Question 28

electricity moves through the heart on a _____ axis

Answer 28

60 degrees

Question 29

what is happening during each of the events during a single heart beat on an ECG?
– P wave
– PR segment
– QRS complex
– ST segment
– T wave

Answer 29

– atrial contraction
– ventricular filling
– ventricular contraction
– “plateau phase” of ventricular relaxation
– ventricular relaxation

Question 30

P wave
– ___ voltage
– ____ depolarization/contraction

QRS complex
– ____ voltage
– ______ depolarization/contraction

T wave
– should match what other part?
– _____ repolarization/relaxation

Answer 30

– low
– atrial

– high
– ventricular

– QRS deflection
– ventricular

Question 31

explain what the ST segment is normally?

Answer 31

time between completion of depolarization and onset of repolarization

Question 32

a standard ECG has _____ electrodes & _____ leads

Answer 32

10
12

Question 33

what kind of ECG are you most likely to see clinically?
– what are the placements of the electrodes?
– where would you place the lead?

Answer 33

5 lead ECG
– RA, RL, LA, LL
– V or C

** white on right, clouds over grass, smoke over fire, i love chocolate

Question 34

why would a 12 lead ECG be used?
– where do you place the electrodes?

Answer 34

diagnostically to determine the problem: where in the heart or its electrical conduction is there a problem
– RA, RL, LA, LL, V1-V6

Question 35

if the problem in the heart is on the ____ side of the heart, then the problematic segment will appear where on the ECG?
– lateral
– inferior
– anterior

Answer 35

– I, AVL, V5, V6
– II, III, AVF
– V1-V4

** reference slide 33

Question 36

how do you calculate HR from an ECG strip?

Answer 36

300/# of big boxes between R waves
OR
1500/# of little boxes between R waves

Question 37

what are the 5 things used to interpret an ECG?

Answer 37

rate
rhythm
regular QRS complexes??
does each QRS have a P wave?
are P waves regular or irregular?

Question 38

** do we have to know all lab values from charts? **

Question 39

arterial blood gas lab values:
– pH
– PaO2
– PaCO2
– Bicarbonate (HCO3)

Answer 39

– 7.35 - 7.45
– 80-100
– 35-45
– 22-26