Cardiac function measurements Flashcards Preview

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Flashcards in Cardiac function measurements Deck (29):
1

What is a doppler electrocardiography?

Measures and visualizes the speed and direction of blood flow
- Red= hot=towards
-Blue= cold= away from

2

What is a normal ejection fraction?

55% and above

3

Increase or decrease in contractibility leads to downward shift of ESPVR line? Name a cause

Decreased contractibility causes by heart disease

4

How would a vasoconstrictor affect the ESPVR line?

increases after load and thus increase contractibility

5

What is Fick's principle?

Calculates the rate at which a substance is being added to or removed from the blood as it passes through an organ

6

What is the most accurate measurement of CO? What else is this good for?

Using Fick's Principle
Q= Xtc/(Xa-Xv)

Tissue metabolism as well

7

What is a cardiac index?

Cardiac output/Body surface area
- use the Namogram scale using weight and height

8

What does the P wave represent?

Atrial depolarization

9

What does the flat line between the P wave and QRS complex mean?

Pause that allows the ventricles to fill

10

What is the QRS complex represent?

Ventricular depolarization

11

What does the ST segment represent? What is responsible for this?

Plateau phase of ventricular AP
- Ca2+

12

What does the PR interval represent?

Conduction time through the atria and AV node

13

What does the QT interval represent?

Total time of ventricular systole

14

What do the smallest boxes on an EKG represent in time?

0.04 seconds

15

What does 1 large box represent?

0.2 seconds

16

In Einthoven's Triangle where are the leads?

RA- both neg
LA- One neg one positive
LL- Both pos

17

Where are leads 1,2 and 3?

1. RA to LA
2. RA to LL
3. LA to LL

18

What doe positive and negative inflections of the EKG represent?

1. pos- moving toward a positive charge
2. moving away from a pos charge

19

Where does the depolarization begin of the QRS complex?

Left intra-ventricular septum

20

Why does the T wave a repolarization effect have a positive inflection on EKG?

Negative wavefront moving away from positive charge (towards negative). Thus double negative making a positive wave form

21

What is the mean electrical axis?

The orientation of the Cardiac dipole during the most intense phase of ventricular depolarization

22

What are normal, left and right axis deviations?

-30-90 degrees= normal
90= right axis deviation

23

Which lead should have the largest R wave?

Lead 2

24

What are Augmented leads?

For 6 lead EKG
- Named for the physical location on the body voltage recording the + pole

25

What are aVR,aVL and aVF? What are their perpendiculars?

aVR- Starts RA and 3
aVL- Start LA and 2
aVF- Start LL and 1

26

What are the degrees of the a 6 lead EKG?

1. 0
2. 60
3. 120
aVR. -150
aVL. -30
aVF. 90

27

How does one calculate the mean electrical axis?

1. Calculate by finding largest R wave and this is your dipole. If wave is negative then its 180 degrees of dipole

2. Determine lead that is most equiphasic QRS complex. Which lead is 90 degrees away from that

28

What is the limit of the 6 lead EKG? What solves this?

6 lead is 2d. If you want 3d view you need a 12 lead.

29

What are the additional leads of the 12 lead called?

Precordial unipolar leads to view transverse plane
v1-v6