echocardiography Flashcards
how is epss an indirect measurement for systolic function
Lv dimensions are proportional to the diastolic left ventricular volume, and the maximal diastolic excursion of the mitral valve is proportional to itral stroke volume, the ratio of the two dimensions will be proportional the the ejection fraction
How does the aortic valve opening on M mode change with DCM
The aortic valve opening is normally quick, forming a box-shaped profile. In DCM, due to reduced forward flow, there is gradual closure of the valve, which results in more coffin-like shape
What is the descent of the base ?
Old unused measurements look at the descent of the heart base towards the apex as an assessment of systolic function. Measurements >10mm are normal.
How do you determine stroke volume of the LV with VTI
Measure the VTI of the LVOT, times this by the cross-sectional area of the LVOT
Show the formula for calculating stroke volume with VTI
IF you have cyclical (every other) variation of VTI (high->low->high-> low) this can be an indication of what form of pulse and dysfunction
Pulsus alternans - sign of advanced ventricular systolic dysfunction
what assumption does LV stroke volume using VTI assume?
That there is no aortic insufficiency
What is a major source of error when calculating VTI?
Not accurately measuring the orifice area. As the measurement for stroke volume using VTI requires the square of the radius of the LVOT, the error can be amplified exponentially.
How can you assess systolic function through dP/dt
What is a B-bump on M-mode of the mitral valve an indicator of ?
This is associated with elevated LA pressure, which in turn reflects a LV end-dyastolic pressure, typically exceeding 20mmHg. This can add validity to an assessment of diastolic dysfunction when associated with pseudonormal mitral inflows
Describe the findings of pulmonary vein flow profiles in a normal individual.
Normal pulmonary vein flow occurs in both systole and diastole, and there is a brief retrograde flow that corresponds to atrial contraction (A-wave)
what changes do you see to pulmonary flow profiles with diastolic dysfunction?
You see increasingly prominent A-flow reversal and decrease in systolic flow the more progressive the diastolic dysfunction becomes
What ancillary imaging can be used to determine if a mitral inflow profile is normal or pseudonormal?
Tissue Doppler imaging, pulmonary vein profiles
How may a Valsalva manoeuvre help identify abnormal relaxation when you have a pseudonormal profile?
During Valsalva, flow into the left heart is reduced, and left atrial and ventricular diastolic pressure is decreased, resulting in a reduction in the E-wave velocity and reversal of the pseudonormal E/A ratio to reveal a pattern of abnormal relaxation.
How can the colour M mode of mitral inflows assess diastolic function?
The velocity of propagation (Vp) can be measured from the slope of the leading edge of the colour M mode profile. lower the VP the more significant the diastolic dysfunction
