Tissue Doppler Flashcards
Tissue Doppler Imaging
- Mitral / Tricuspid annular velocities
- high amplitude, low velocity signals (low pass filter on)
- systolic (s’) , early (e’) , late (a’)
- angle dependent (keep < 20º)
- average ≥ 3 cardiac cycles
Diastolic Function
• e’ < 8 cm/s = bad • lateral e’ > septal e’ - exception: constrictive pericarditis (lateral < septal) annular reversus • e’ > 10 cm/s = good • a’ < 10 cm/s = good • e’ / a’ < 1 = bad • s’ > 8 = good • s’ < 5 = bad
TDI : detection of ischemia
- s’ , e’ , e’/a’ decrease
- TDI changes occur faster than reduction of systolic excursion & wall motion changes
- post systolic shortening
- isovolumic contraction velocity decreases
- prolongation of the Q-to-peak-s’ time interval
- ECG-Q-to-e’ onset > ECG-Q-to-TMF-E onset
TDI limitations
- mitral annular disease / tethering
- time intervals require regular rhythm & stable HR
- regional
- normal patients —> preload dependent
- angle dependent
Tamponade vs Constrictive Pericarditis
• Transmitral Inflow
- RICM : e’ < 8 cm/s
- CP : e’ > 10 cm/s ; lateral e’ < septal e’
TDI for diastology
- e’ > 10 cm/s —> done.
- e’ < 8 - 10 —> look at other stuff ….
- E/e’ > 13 —> elevated LAP
TDI for MPI
• measures both systolic and diastolic function
• lower number = better
•MPI = (IVCT + IVRT) / ET
- normal = 0.4
- elevated MPI = abnormal systolic & diastolic function
Right Heart
• RV s’ < 10 cm/s = low in young healthy people
• IVA = 1.4 +/- 0.5 m/s^2 (wide confidence levels = not very reliable)
• MPI = (IVCT + IVRT) / ET
- (TR jet duration - ET) / ET
- relatively independent of HR, preload, and afterload
- measures both systolic and diastolic function
- > 0.5 predictive of HD instability and mortality after valve surgery
•Strain Rate = (V2 - V1) / x
- not used often perioperative but useful in detecting early onset of ischemia prior to detection of WMA