Echo - chamber quantification Flashcards
What is the general rule for chamber measurements in regards to heart rate and beats?
- Perform on more than one cycle (inter-beat variability)
- Sinus rhythm - average 3 beats
- Atrial fibrillation - average 5 beats
What Echo modes can be utilized in linear measurements?
- 2D
- M-mode
What Echo mode can be utilized to obtain volumetric measurements?
- 2D
- 3D
Where should the LV end-diastolic dimension be measured?
- perpendicular to the LV long axis
- at or immediately below the mitral valve leaflet tips
- 2D >> M-mode (will OVERESTIMATE)
- will avoid oblique measurements
- use guided M-mode if needed
What are the advantages of linear measurements in M-mode?
- reproducible
- high temporal resolution
- published data
What is the preferred method of LV volume measurement?
- 2D Biplane Disc Summation (modified Simpsons)
- sum of πr2h
How do you perform the 2D Biplane Disc Summation (modified Simpsons) method of LV volume measurement?
- trace the blood-compacted tissue interface in 2 and 4 chamber apical views
- straight line at mitral valve level (connect opposite sections of mitral ring)
What are methods for calculation of LV systolic function?
- Volumetric LVEF
- (LVEDV-LVESV)/LVEDV x 100
- Biplane method of discs (modified Simpson’s) ***currently recommended
- 3D can be used when available/feasible
What is a severely abnormal LVEDD (cm)?
- males
- females
- > 6.8 cm
- > 6.1 cm
Define End-Diastole in the Echo Cardiac Cycle
-frame after MV closure
or
-frame with largest LV dimension/volume
Define End-systole in the Echo Cardiac Cycle
-frame after AV closure
or
-frame with smallest LV dimension/volume
What is the standard IVSd (cm) for men and women?
men: < 1.0cm
women: < 0.9cm
What is the standard PWT (cm) for men/women?
- men: < 1.0 cm
- women: < 0.9cm
What is IVSd?
interventricular septal end-diastolic dimension
what is PWT?
posterior wall thickness
What is LVIDd?
left ventricular internal diameter end-diastolic dimension
what is LVIDs?
left ventricular internal diameter end-systolic dimension
What is the standard measurement for LVIDd?
- men: < 5.8cm
- women: < 5.2cm
What is the standard measurement for LVIDs?
- men: < 4.0cm
- women: < 3.5cm
What is normal LVEF?
- men: > 52%
- women: > 54%
What is normal LVEDd in males?
Severely abnormal?
- 4.2-5.8 cm
- > 6.8 cm
What is the (males) normal LV diastolic volume index (mL/m2)?
Normal LV systolic volume index (mL/m2)?
Severely abnormal LV diastolic volume index (mL/m2)?
- < 74 mL/m2
- < 31 mL/m2
- > 100 mL/m2
What is normal LVEDd in females?
Severely abnormal?
- 3.8-5.2 cm
- > 6.1 cm
What is the (females) normal LV diastolic volume index (mL/m2)?
Normal LV systolic volume index (mL/m2)?
Severely abnormal LV diastolic volume index (mL/m2)?
- < 61 mL/m2
- < 24 mL/m2
- > 80 mL/m2
How to calculate indexed measurements?
Indexed measurements = measurement / BSA
56 year old female has LV mass of 98 g/m2 and relative wall thickness of 0.38. What is her LV chamber geometry?
Eccentric hypertrophy
Describe method for determining LV mass/LV mass index/Relative wall thickness
What is the formula for RWT?
RWT = 2 x PWT / LVEDD
What is the linear method (cube formula) for determining LV mass?
LV mass = 0.8 x 1.04 [(IVS + LVIDD + PWT)3 - LVIDD3] + 0.6g
- LV mass = (LV volume epicardium - LV volume endocardium) * 1.04
**1.04 = specific gravity of myocardium
What adverse cardiovascular outcomes are associated with increased left atrial size?
Increased incidence of:
- Atrial fibrillation
- Stroke
- post-MI mortality
- death and hospitalization in patients with dilated cardiomyopathy
What is alternative method of calculating the LV mass?
- Linear Method
- Cube formula
- 2D Based formula
- Truncated Ellipsoid
- Area-length
- 3D method
- direct measurement (without geometric assumptions)
What is the relationship between pulmonary arterial hypertension and left atrial size?
PAH is not associated with increased left atrial size
What is the Law of LaPlace?
- describes the factors that determine left ventricular wall stress, which is a major determinant in myocardial oxygen demand
- LV wall stress is the force acting against the myocardial cells
- LV wall stress is directly proportional to LV pressure and radius
What is LaPlace’s law (equation) for LV wall stress?
LV wall stress = (LV pressure x LV radius) / 2 x LV wall thickness
Describe the changes to LaPlaces law with pressure overload states?
- Concentric hypertrophy (HTN, AS)
- Sarcomeres added in parallel
- Normal or small LV cavity size with thick walls
- Increased:
- LV pressure
- LV wall thickness
- LV mass
- RWT
LV wall stress = ( Î LV pressure x LV radius) / 2 x Î LV wall thickness
Describe the changes to LaPlaces law with volume overload states?
- Eccentric hypertrophy
- Increased diastolic chamber size
- No change in RWT
- Sarcomeres added in series
- Increased:
- LV radius (volume)
- LV wall thickness
- LV mass
LV wall stress = ( LV pressure x Î LV radius) / 2 x Î LV wall thickness
What is a normal LV global longitudinal strain?
~ - 20%
Explain how to estimate RA pressure using IVC measurements?
- IVC diameter < 2.1 cm + collapse > 50% (with sniff) –> RA pressure = 3 mmHg (normal
- IVC diameter > 2.1 cm + collapse < 50% ( with sniff) –> RA pressure = 15 mmHg
- RA pressure = 8 mmHg –> IVC parameters don’t fit this schema
What are two situations in which estimation of RA pressures are unable to be assessed?
- Ventilators
- Young healthy athletes
**
What are the six quantitative parameters to evaluate RV systolic function (and abnormal values)?
- TAPSE ( < 17 mm)
- Tricuspid annular velocity (< 9.5 cm/s)
- RV 2D fractional area change ( < 35%)
- RV index of myocardial performance ( > 0.43 for pulsed Doppler and > 0.54 for tissue doppler)
- 3D RV EF ( < 45%)
- RV free wall strain ( > - 20%)
What two RV quantitative parameters are associated with poor prognosis in patients with CHF and PH?
- TAPSE
- Abnormal RV free wall strain
What is not a cause of left atrial enlargement ?
ASD
- LAE reflects increased wall tension as a result of chronically increased LAP
- ASD commonly cause volume overload of the RA > LA
What are adverse outcomes associated with LAE?
- Increase incidence of A-fib and Stroke
- Increase the risk of overall mortality post-MI
- Increase the risk of death and hospitalization in patients with dilated cardiomyopathy
Describe LA size assessment in Echo
- measurements should be obtained at end-systole
-
Dedicated LA images
- Avoids foreshortening the LA
-
Maximize left atrial length
- Anteroposterior measurement obtained from PLA window (highly reproducible), frequently underestimates the LA size
What should be included/excluded when tracing the left atrial border?
- Included:
- AV interface should be represented by the mitral annulus plane, not the tipe of the mitral leaflets
- Excluded:
- Pulmonary vein confluences
- LA appendage
What is the relationship between LA volume (on 2D Echo) and CT/MR volumes?
LA volume is underestimated on 2D Echo when compared to CT/MR
What is the difference between LA volumes obtained in A4C and A2C views?
A4C views typically 1-2 mL/m2 smaller than A2C views
What method is not recommended for calculation of LA volume?
Ellipsoid model using three linear measurements
- relative inaccuracy of these linear measurements limits this method
What are reccommended methods for measuring LA volume?
-
Disc summation method (Biplane method of discs) from a single or biplane imaging (assuming oval shape)
- ASE recommended
- Area-Length Method
- Biplane method using left atrial areas and lengths from the A4C and A2C views
- 3D method
What is one limitation of 3D Echo in assessment of LA volume?
Lack of standardized methodology
- 3D >> 2D Echo in assessing LA volume –> correlates better with CT/MR volumes
How does RA volume measurement differ from LA volume measurement?
Right atrial volumes can be calculated from biplane views
- RA volume is derived from A4C view using the area-length or disc summation methods
- RA volume smaller than LA volume
- RA volumes differ between males and females
What is the recommendation for reporting RA size?
A4C view
Indexed for BSA
Differentiated by gender