8/3- How to Msr Cardiac Fct at the Bedside Flashcards
Pulmonary artery pressure? (mmHg)
15-30/3-12
Right ventricular pressure? (mmHg)
15-30/0-8
Aortic pressure? (mmHg)
100-140/60-90
Left ventricular pressure? (mmHg)
100-140/5-12
Pulmonary capillary wedge pressure? (mmHg)
5-`1
The right atrial pressure waveform has:
- _(#)_ positive waves (examples)
- _(#)_ negative deflations (examples)
Three positive waves:
- a wave: atrial systole (follows ECG “P” wave)
- c wave: TV closure
- v wave: atrial filling (followed by TV opening)
Two negative deflations:
- x-descent: atrial relaxation
- y-descent: rapid atrial emptying
Right ventricular pressure has:
- ______ peak pressure
- ______ pressure phases (examples)
Systolic Peak Pressure
Diastolic Pressure Phases
- Rapid filling phase
- Slow filling phase
- Atrial contraction
What is this? Label?
a wave- atrial kick
c wave- closure of AV valve
x descent- atrial relaxation
v wave- atrial filling from jugular vein (peaks when AV valve closes)
y descent- rapid early emptying of atrium (atrial counterpart of rapid early filling phase of ventricle) Which descent(s) is/are clinically useful?
**Change in y descent is very important sign of abnormality!! Critical!
** x descent abnormality (steeper/shallower) has no specificity for cardiac disease
Measurements of systolic function (4)?
- Hemodynamic measurements (4)
- Regional ventricular function
- Left ventricular mass
- Ventricular response to stress
What are hemodynamic measurements of cardiac function?
- Ventricular volume
- Ejection fraction
- Cardiac output
- Vascular resistance
How do we measure ventricular volumes?
Systolic and diastolic volumes can be measured by echocardiography or angiography (nuclear or contrast dye)
What is typical LV end-diastolic volume?
(don’t need to memorize)
79 +/- 11 mL/m2
What is typical LV end-systolic volume?
(don’t need to memorize)
28 +/- 6 mL/m2
Equation for stroke volume?
EDV - ESV
(Typically LV: 79 - 28 ~ 51 mL/m2)
What is left ventricular ejection fraction?
What does it indicate?
What increases/decreases it?
Ratio of stroke volume to end-diastolic volume: SV/EDV
- Measure of cardiac performance
- Increases with increase in preload and contractility or decrease in afterload
What is normal LVEF?
67 +/- 7% (> 50%)
What is cardiac output?
Blood flow to systemic circulation in every minute
CO = SV x HR
(SV: blood ejected per beat)
What is cardiac index?
Cardiac output/body surface area
CI = CO/BSA
How can we measure CO? (2 main methods)
Which is used more often?
- Thermodilution method using a Swan Ganz catheter** more common
- Doppler echocardiography (complicated)
Method behind measuring CO by Swan Ganz catheterization?
Thermodilution method using a Swan Ganz catheter:
- Balloon-tipped catheter floated into the pulmonary artery from a systemic vein
- 10 mL saline injected into the RA and resultant change in PA blood temperature (detected by a thermal sensor) is used to compute the cardiac output
- Then we infer left side CO from right side (they are equal!!!)
T/F: Left sided cardiac output can be estimated from the right side (via Swan Ganz catheterization)?
True
Right side cardiac output approximates the left
What can we measure by Swan Ganz catheterization?
- Cardiac output
- Pulmonary capillary wedge pressure
As the balloon is occluded, the P measured at the catheter tip is the pulmonary cap wedge P which reflects the left atrial pressure transmitted through the pulmonary circulation into the pulmonary caps
What is vascular resistance? Types?
Ratio of pressure gradient to blood flow
- Systemic vascular resistance
- Pulmonary vascular resistance
Equations for:
- Systemic vascular resistance
- Pulmonary vascular resistance
Relative relationship?
Systemic vascular resistance: SVR = (AO-RA)/CO Pulmonary vascular resistance: PVR = (PA-LA)/CO
SVR is ~10x higher than PVR
What is regional ventricular function?
Extent of myocardial thickening and wall motion of various myocardial segments
How is regional ventricular function measured?
- Echocardiography
- Radionuclide angiography
- Cardiac catheterization with contrast dye angiography
How may wall motion be described?
- Normal
- Hypokinetic
- Akinetic
- Dyskinetic
How is left ventricular mass most commonly measured?
Echocardiography
What can increase LVM (left ventricular mass)?
HYPERTROPHY
- Either concentric or eccentric due to pressure or volume load
Left ventricular hypertrophy predicts what?
Left ventricular hypertrophy predicts a worse clinical prognosis in patients with hypertension and various cardiac diseases
Why do we measure ventricular response to stress?
- To assess overall ventricular reserve
- To determine functional significance of coronary stenosis in pts with CAD
Types of stress tests (3)? Examples?
- Isotonic exercise: treadmill and bike
- Isometric exercise: handgrip
- Pharmacologic: dobutamine, adenosine, or dipyridamole
What is a key predictor of significant coronary artery disease?
- Development of a regional wall motion abnormality INDUCED during any stress test is a HALLMARK of ischemia due to coronary artery disease (CAD)
- This is a major reason for using stress tests to assess regional ventricular function response to stress
What are measurements of diastolic function?
- Measure end-diastolic pressures in LV and RV during cardiac catheterization
- Diastolic filling parameters by Doppler echocradiography
Key points of measurements of cardiac function:
- Atrial waveforms:
- Ventricular waveforms:
- Ventricular Diastolic Pressure = ____
- RAP= __; RVP= __
- LAP= __; LVP= __
- Cardiac performance vs. contractility
- Systolic function: _____________
- Cardiac performance: measured by _________ & influenced by _______
- Contractility: ___________- conditions=inotropic state
- Systolic function: _______
- LVEDV= ___ ;LVESV=____; SV= ___
- EF= ___(%); EF= ______
- CO= ___; CI= ___
- SVR= _______
- Resistance= _____
Key points of measurements of cardiac function:
- Atrial waveforms: a, c & v (+); x & y (-)
- Ventricular waveforms: early/late filling
- Ventricular Diastolic Pressure = Atrial Pressure
- RAP=0-8; RVP=15-30/0-8 mm Hg
- LAP=3-12; LVP=100-140/3-12 mm Hg
- Cardiac performance vs. contractility
- Systolic function: volumes, EF, CO, SVR
- Cardiac performance: measured by EF, SV & CO & influenced by contractility
- Contractility: inherent ability to generate power independently of loading conditions=inotropic state
- Systolic function: volume, EF, CO, SVR
- LVEDV=79+11; LVESV=28+6; SV=D-S
- EF= SV/EDV (%); EF= 67+7 (>50%)
- CO= SV x HR (volume ejected/beat x number of heart beats); CI= CO/BSA
- SVR= pressure drop (AP-RAP)/flow (CO)
- Resistance = pressure/flow
All of the following are associated with pressure overload concentric LVH except:
A. Systemic hypertension
B. Aortic stenosis
C. Mitral regurgitation
D. Pulmonary hypertension
All of the following are associated with pressure overload concentric LVH except:
A. Systemic hypertension
B. Aortic stenosis
C. Mitral regurgitation
D. Pulmonary hypertension
Which of the following has the highest wall stress?
A. HTN with concentric LVH
B. Aortic stenosis with concentric LVH
C.
D.
Which of the following has the highest wall stress?
A. HTN with concentric LVH
B. Aortic stenosis with concentric LVH
C.
D. ***
which of the following is the correct way of calculating cardiac output?
A. SV x VR
B. HR x EDV
C. SV x HR
D. HR x CI
which of the following is the correct way of calculating cardiac output?
A. SV x VR
B. HR x EDV
C. SV x HR
D. HR x CI
All of the following affect wall stress except:
A. IVP
B. HR
C. Ventricular size
D. Wall thickness
All of the following affect wall stress except:
A. IVP
B. HR
C. Ventricular size
D. Wall thickness
Which of the following phases of diastole occurs first?
A. Atrial kick
Which of the following phases of diastole occurs first?
A. Atrial kick
True/False questions
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