Computation constant must match catheter + injectate in monitor
Why this matters: The TD computation constant programmed in the hemodynamic monitor is specific to catheter size + injectate volume/temperature. A mismatch produces systematic TD CO error. Verify the constant matches your setup. This does not affect Fick or LaFarge calculations.
Pressures (mmHg)
a/v/mean
sys/dia/EDP
sys/dia/mean
a/v/mean
sys/dia/EDP
sys/dia/mean
Oximetry
%% (PA sat)
mmHgmmHg
Enter saturations as percentages (e.g., 92.8 not 0.928). Calculator converts automatically.
SEP = ejection time/beat × HR. Typical: 0.30–0.35 sec/beat → 20–25 sec/min. Measured from AV open to dicrotic notch. Type over the SEP to use a measured value — it is kept, and clearing it hands the box back to the ejection time.
Mitral Valve (MVA)
mmHg (transmitral gradient)
sec/beat→sec/min
DFP = filling time/beat × HR. Typical: 0.40–0.50 sec/beat → 30–40 sec/min. Shortened in tachycardia. Average ≥5 beats in AFib. Type over the DFP to use a measured value — it is kept, and clearing it hands the box back to the filling time.
Aortic Valve (AVA) — Per-Beat Data
Enter gradient and ejection time for each beat. Minimum 5 beats recommended. Empty rows are ignored.
Beat
ΔP (mmHg)
Eject time (s)
AVA (cm²)
1
—
2
—
3
—
4
—
5
—
6
—
7
—
8
—
9
—
10
—
Mitral Valve (MVA) — Per-Beat Data
Enter gradient and filling time for each beat. Minimum 5 beats recommended. Empty rows are ignored.
Beat
ΔP (mmHg)
Fill time (s)
MVA (cm²)
1
—
2
—
3
—
4
—
5
—
6
—
7
—
8
—
9
—
10
—
Shunt Oximetry Run
ASD with PH — a different patient from the RHC example
Workflow: On routine RHC, draw 1 SVC + 1 PA sample. If PA sat is ≥ 8% higher than SVC → significant L→R shunt suspected → perform full oximetry run below to localize the shunt level and quantify Qp/Qs.
Screening (minimum required)
%%
These two samples alone detect most L→R shunts (≥ 8% step-up = significant).
Full Oximetry Run (for localization & Qp/Qs)
Enter all samples obtained. At minimum, need SVC + IVC (for MV O₂) and PA (for Qp/Qs). More samples = better localization. RA best sampled at mid-RA level.
SVC
%High SVC entered above
IVC (needed for MV O₂)
%At level of diaphragm, beyond renal veins
Right Atrium (step-up here → ASD)
%%%
Mid-RA least affected by IVC/coronary sinus streaming. Multiple samples preferred.
Right Ventricle (step-up here → VSD)
%%
Pulmonary Artery (step-up here → PDA)
PA main entered above in screening%%
PV O₂ & FiO₂
%
If SaO₂ ≥ 95% on room air → no significant R→L shunt → PV O₂ ≈ SaO₂. If R→L shunt suspected, use wedge PA sample or assume 98%.
%Room air = 21%. If > 30%, simplified Qp/Qs is inaccurate — must use full O₂ content with dissolved O₂.
Collect all samples within a few minutes to minimize error from fluctuations in anxiety/wakefulness.
O₂ Content
CaO₂—mL O₂/dL
CvO₂—mL O₂/dL
a-vO₂ diff—mL O₂/dLnormal: 3.5–5.5
Fick Cardiac Output
Fick CO—L/minnormal: 4–8
Fick CI—L/min/m²normal: 2.5–4.0
SV—mL/beatnormal: 60–100
SVI—mL/beat/m²normal: 33–47
Thermodilution
TD CO—L/minnormal: 4–8
TD CI—L/min/m²normal: 2.5–4.0
Pulmonary Hemodynamics (using Fick CO)
TPG—mmHgmPAP − PCWP
DPG—mmHgdPAP − PCWP; not used in the 2022 classification
LV–Ao Peak-to-Peak Gradient—mmHg≥ 30 significant; ≥ 50 severe
Gorlin Valve Areas (using Fick CO)
Aortic Valve Area (AVA)
AVA—cm²normal: > 2.0
Severity
AVA (cm²)
Normal
> 2.0
Mild AS
1.5 – 2.0
Moderate AS
1.0 – 1.5
Severe AS
0.6 – 1.0
Critical AS
≤ 0.6
2020 ACC/AHA VHD Table 13: severe AS is Vmax ≥ 4 m/s or mean ΔP ≥ 40 mmHg. An aortic valve area ≤ 1.0 cm² is typical but not required in stages C and D1, and is a defining criterion in low-flow, low-gradient severe AS (D2, D3). An area of exactly 1.00 cm² therefore belongs in the severe band — this ladder is inclusive at 1.0 exactly as the mitral ladder is inclusive at 1.5. Only that boundary comes from the guideline: Table 13 grades mild and moderate AS by velocity and gradient and prints no valve-area bands for them, and it defines no critical-AS stage, so the ≤ 0.6, 1.0–1.5, 1.5–2.0 and > 2.0 rows are catheterization convention.
Mitral Valve Area (MVA)
MVA—cm²normal: 4 – 6
Severity
MVA (cm²)
Normal
4 – 6
No mitral stenosis
2.5 – 4
Progressive MS
1.5 – 2.5
Severe MS
≤ 1.5
2020 ACC/AHA VHD: severe MS is a valve area ≤ 1.5 cm² (Stage C/D) — the threshold every Class 1 PMBC recommendation is keyed to. That boundary is the only row here the 2020 document defines. The others are catheterization convention and are printed as such: the guideline puts no ceiling on Stage B progressive MS (it is any area above 1.5) and has no “no MS” band. A “very severe MS (≤ 1.0)” sub-tier appears in pre-2020 texts only; Table 16 has no such row, so this page no longer prints one (retired 2026-09-21, after Echo Calc and the waveform tool). They exist so that the label printed beside a number is true across the whole reportable range (0.4–6 cm²), not because the guideline draws them.
Gorlin is flow-dependent. Low CO → falsely small valve area. Tachycardia → major effect on MVA (short DFP), minimal on AVA. Use Fick CO for Gorlin.
Quality Checks
Enter values to see quality checks.
Interpretation
Enter hemodynamic data to generate interpretation.
EVALUATION REPORT
Mixed Venous O₂
MV O₂—%Flamm formula
O₂ Step-Up Detection & Localization
Enter oximetry run values to detect step-ups.
Shunt Quantification
Qp/Qs—(ratio)
Qp—L/minpulmonary flow
Qs—L/minsystemic flow
Q effective—L/minnon-shunted flow
L→R shunt—L/min
R→L shunt—L/min
Qp/Qs
Interpretation
< 1.0
Net right-to-left shunt
1.0–1.4
No significant shunt
1.5–1.9
Small-moderate L→R shunt
2.0–2.9
Large L→R shunt (consider repair)
≥ 3.0
Very large L→R shunt (repair indicated)
Shunt-Adjusted Vascular Resistance
PVR (Qp)—WUnormal: < 2
SVR (Qs)—WUnormal: 10–20
PVR/SVR—(ratio)> 0.67 = Eisenmenger concern
In shunt physiology, use Qp (not TD CO) for PVR and Qs for SVR.