CC12: Flow and valve area Flashcards
Aortic valve normal area
2.5-3.5cm^2
Mitral valve normal area
4-6cm^2
Pulmonary valve normal area
2.5-3.5cm^2
Tricuspid valve normal area
5-10cm^2
Congenital defect that affects pulmonary valve
Tetralogy of Fallot
Why should A wave of PCW and LVEDP be the same?
A wave of PCW = atrial contraction
LVEDP = Ventricular diastole
Valve is open so pressure should be same
How does ASD affect A and V wave in atrium?
-Higher V wave
-Atria is relaxing during V wave
-ASD causes more atrial filling
What should a normal V wave be?
<12
Which valves are associated with diastolic filling period (DFP)?
-Mitral
-Tricuspid
Which valves are associated with systolic ejection period (SEP)
-Aortic
-Pulmonary
What is systolic ejection period (SEP)?
-SEP starts with the opening of the aortic valve and finishes at the dicrotic notch
-Amount of time the ventricles spend in systole per minute
What is the diastolic filling period (DFP)?
-DFP starts with the closure of the aortic valve and finishes at the start of systole
-Amount of time the ventricles spend in diastole per minute
What is the Hakki equation?
What variables affect pressure gradients?
Physiological
-Rate of blood flow
-Resistance to flow
-Proximal chamber pressure/compliance
Anatomical
-Shape/length of valve orifice
-Tortuosities of vessel
-Multiple/serial lesions
Artifactual
-Mis-calibrated pressure transducer
-Pressure leaks (catheter or manifold)
-Pressure tubing type/ length/ connectors
-Air in system
-Catheter size
-Fluid viscosity (contrast)
-Position of catheter holes
What are the pressures?
-Left side
-Femoral artery and LV
-100mmHg pressure gradient
-Severe aortic stenosis
What is the pathology?
HOCM
What waveform is this?
-Left ventricle
-Left atrium (PCW)
-a wave and LVEDP should be the same
What indicates regurgitation through valve
V wave >12
Left atrial vs PCW waveform
-Left atrium descends sharper
Use of PCW in assessment of mitral stenosis
-Using PCW instead of LA can increase area under the curve
-This falsely increases the mean gradient across the valve
-Pseudo mitral stenosis
Formula for valve area?
An individual undergoes left and right cardiac catheterisation for the evaluation of aortic stenosis. Measurements includes an aortic pressure of 120/60, LV pressure of 170/15, cardiac output of 3.5 litres/minute. What is the aortic valve area?
Mean gradient across Tricuspid and Pulmonary valve
-Rare in adults
-Mean gradient of 5mmHg is enough to cause symptoms
-Gradients <50mmHg have been well tolerated
What is constrictive pericarditis?
-Constriction of the heart due to a rim of fibrosed or calcified pericardium
-Causes inadequate filling of the heart
-There is a small volume pulse
-ECG is low voltage and with flat/inverted T waves, broad/notched P waves
What is restrictive cardiomyopathy?
-Non-dilated rigid ventricle
-Causes severe diastolic dysfunction and restrictive filling
-Produces haemodynamic changes similar to constrictive pericarditis
What do constrictive pericarditis and restrictive cardiomyopathy lead to?
-HFpEF
-Abnormal ventricular filling causes similar clinical and haemodynamic features
-Treatments are different so they must be differentiated from each other
What causes changes in LV-RV pressure relationship?
Ventricular septal interaction
What conditions can changes in LV-RV relationship occur in?
-Constrictive pericarditis
-BBB
-Pulmonary HTN
-MI
-RV volume overload
How RV and LV pressure trace differ?
-Different end-diastolic pressure (EDP)
-Separate by >5mmHg in early and late diastole
-A waves differ in size due to lower compliance (stiffer) LV
How does constrictive pericarditis affect LV-RV pressure trace?
-LV and RV have matching diastolic pressure
What happens to ventricles in constriction defects?
-Discordant ventricles
-LV systolic pressure falls
-RV systolic pressure rises
What happens to ventricles in restrictive defects?
-Concordant ventricles
-LV systolic pressure falls
-RV systolic pressure falls
How does inspiration affect constrictive and restrictive defects?
Constrictive:
-Early diastolic gradient decreases with inspiration
Restrictive:
-No change
Features of HOCM
-Often involves interventricular septum and obstructs the LVOT
-Familial and genetic
-ECG shows ST changes, LVH and LAE
Features of HCM
-Massive thickening of ventricles
-LV is stiff with impaired filling
-LVEDP is raised
-Lungs become congested (SOB)
