Cardiac Hemodynamics Flashcards
BP >140/90 on 2 separate occasions
High BP
Average pressure over the entire cardiac cycle
Mean pressure
How to calculate mean pressure (MAP=)
MAP= [(2xdiastolic) + systolic]/3
The difference of pressure between two adjacent locations within the heart or vascular system
Pressure gradient
Bernoulli’s equation states what?
As pressure gradient increases, velocity increases
Change in pressure = 4 x Velocity^2
The 4 phases of the cardiac cycle
- IVCT
- Systole
- IVRT
- Diastole
The period of time between MV closure and AV opening
IVCT
How long does IVCT last?
30-50 ms
How long does ventricular systole last?
200-300 ms
The period of time after the AV has closed but before the MV opens
IVRT
How long does IVRT last?
50-100 ms
3 phases of diastole
- Early/rapid filling
- Diastasis
- Late filling/atrial kick
How long does early filling last?
150-220 ms
Blood ejected from the ventricles with each beat
Stroke volume
How to calculate SV from EDV and ESV
SV= EDV - ESV
Blood pumped from the ventricle in one minute
Cardiac output
How to calculate CO
CO = SV x HR
How to calculate stroke volume using doppler
SV= CSA x VTI
What is the O2 sats in deoxygenated blood?
75%
How is ischemia in the heart felt?
Angina pectoris
4 factors affecting stroke volume
- Preload
- Afterload
- Inotropic force
- Chronotropic force
The amount of blood volume in the ventricle at end diastole
Preload
Increased preload does what to SV?
Increases it
Increased afterload does what to SV and CO?
Decreases it
Increased heart rate does what to SV and CO?
Decreases
Inspiration does what to venous return to the RT heart?
Increases it
Which phase of the cardiac cycle has ventricular pressure falling with all valves closed?
IVRT
Which type of energy contributes the most to pedal edema
Gravitational
Calculate MAP from these variable:
Systolic BP = 130mmHg
Diastolic BP = 90 mmHg
MAP = [(2x90) + 130]/3
103.33 mmHg
The ventricles do about 70-75% of their filling during which stage of the cardiac cycle?
Early filling
Which phase of the cardiac cycle happens when pressure between the atria and ventricles are almost equal?
Diastasis
Which phase of the cardiac cycle is the result of atrial contraction?
Late filling
What is the normal range for mean pressure in the LA
2-12mmHg
Calculate SV and CO with the following values:
LVOT diameter= 20 mm
LVOT VTI = 15cm
HR = 75 BPM
SV = CSA x VTI
=0.785 x 2^2 x 15
=47.1
CO=SV x HR
=3.5 L/min
A high afterload such as high BP for many years can lead to what of the LV?
Hypertrophy
Which law or principle is related to the stretch of the myocardium caused by an increase in volume of blood delivered to it?
Frank-Starling Law
A decrease in inotropic force would lead to an increase in EF? True or false
False
