Siemens ACUSON Cypress

ACUSON Cypress™ Operator’s Manual 6-21
Cardiac Formulas and References
Stroke Volume
TVI is the time velocity integral (m).
Flow Area is derived from the flow diameter (cm
2
).
TVI FLOW AREA
Aortic: AoV TVI LVOT Flow Area
Mitral: MV TVI Mitral Flow Area
Pulmonic: PV TVI Pulmonic Flow Area
Tricuspid: TV TVI Tricuspid Flow Area
ml
Cardiac Output
SV is Stroke Volume (ml).
HR is Heart Rate (bpm).
l/min
Cardiac Index
CO is cardiac output (l/min).
BSA is body surface area (m
2
).
l/min/m
2
Pressure Half
Time
(PHT)
Vmax is Maximum Velocity (m/s).
Deceleration Slope (m/s
2
).
ms
Valve Area by
PHT
PHT is Pressure Half Time (msec).
cm
2
Aortic Valve
Area by the
Continuity
Equation using
V
max
AVA is Aortic Valve Area (cm
2
).
CSA
LVOT
is Cross-sectional Area of LVOT (cm
2
).
Vmax
LVOT
is the maximum velocity in the LVOT (m/s).
Vmax
AoV
is the maximum velocity across the aortic valve
(m/s).
LVOT is Left Ventricular Outflow Tract.
cm
2
TABLE 31. Doppler Formulas (Cardiac)
Type Formula Units
SV TVI Flow Area• 100•=
CO
SV HR•()
1000
--------------------------=
CI
CO
BSA
-----------=
PHT
Vmax 1
1
2
-------–
⎝⎠
⎛⎞
•
Deceleration Slope
----------------------------------------------------
⎝⎠
⎜⎟
⎜⎟
⎜⎟
⎛⎞
1000•=
Valve Area
220
PHT
------------=
AVA CSA
LVOT
Vmax
LVOT
Vmax
AoV
------------------------•=