Module 9 Flashcards
Preload
The volume of fluid remaining in the right ventricle
End of the diastolic pressure
“Stretch”
Afterload
Resistance left ventricle must over come to circulate blood
Heart has to overcome to edjuct blood
The squeeze
Peripheral vascular resistance
1/3
2/3
Systolic and diastolic ?
1/3 systolic
2/3 diastolic
Stroke volume
Is the amount of blood pumped with each contraction of the heart
Dependent on preload and afterload
Heart rate =
Is the number of heart contractions per minute?
Cardiac output
Is the amount of fluid pump by the heart each minute
Cardiac output formula
Co = sv x hr
Automaticity
Generates its own electrical impulses, without stimulation from nerves
Pacemaker
Intercalated discs
Discs that are responsible for automaticity in the heart
Excitability
Ability to respond to an electrical impulse
Conductivity
The ability to conduct excation through the cardiac muscle
Contractiliity
The ability to contract in response to stimulation
How blood flows in the heart
The dominant pacemaker
Sa node
Sa node rate
60-100
Av node rate
60-80
Branches of the av node rate
40-60
Purknje fibers rate
20-50
Which side of the purknje fibers have more branches
Left
Electrical impulses spread from the SA node through the ?
Left and right atrial
Electrical impulses spread from the bundle throughout the ?
Left and right ventricle
What transmits from the SA node signal from the atrium to the ventricles
Av node
What lead do we use
2
Keep going :)
Layers of the heart
P =
Artial depolarization
(Contraction )
QRS =
Ventricular depolarization
Contraction
ST=
Beginning of ventricle repolarization
Relaxation
T=
Ventricular repolarization
:)
Absolute refractory. Period.
The neuron can not fire another action potential
Relative refractory. Period.
Occurs after absolute refractory period and it’s possible for the neuron to fire another action potential
White is always -/+
Red is always -/+
Black is always -/+
White +
Red -
Black both
Order of leads
White is right
Smoke over fire
Grass under white clouds
Lead triangle
Horizontal
ecg strip
Time
Vertical =
Ecg strip
Voltage
Paper moves at
25mm/sec
Millivot =
2 large boxes
Each small square =
Each large square =
1mm/0.04 secs
5mm /0.20 secs
Small strip =
3 small strips =
3 secs
6secs
P-R should be less than
0.20 seconds
One big box
Or five small boxes
QRS should be less than
0.12 seconds.
What are three small boxes
Narrow qrs =
Arterial
Wide qrs =
Ventricular
300 method
Medium accurate
Must be regular
Measure R to R big boxes
300
150
100
75
60
50
43
37
Six second method
Least effective
Can be used for both
Count the number of our waves in six seconds times by 10
1500 method
Has to be regular
Count the number of small boxes are the R to R
Divided by 1500
Most accurate
Cell at rest equals
Inside is more negative
Resting cell membrain potential
Depolarization
Stimulatea NA+ rush into the cell
Inside becomes less negative
Action potential
Repolarization
Sodium potassium pump
Sodium potassium pump
Depolarization and repolarization
Chart
Steps to electrical conduction
Shockable rhythms
Pulseless v tac
V fib
Torsades de pointes
