Module 8

Sources & rules

Every reference range and every rule in the interpretation engine, with the citation behind it. Where the textbooks and guidelines disagree, the competing values are shown rather than silently reconciled.

rules 2026.10-r1-draft

On this page

How the engine works
Kinds of threshold
Reference ranges
Band edges
Rule table
References
Known disagreements
What was verified

How the interpretation engine works

RULES_VERSION 2026.10-r1-draft

The calculator does not contain a hidden model. It derives the standard metrics (cardiac index, resistances, gradients, PAPi, cardiac power) with the formulas shown on the calculator page, runs data-quality checks, and then evaluates a table of 54 declarative rules. Each rule is a condition over the metrics plus teaching text, a tone, and citations, so every statement the app makes can be traced to a threshold and a source.

Declarative rules. A rule is data, not code: { metric, op, value }, a half-open interval, a context flag, or a combination with and / or / not. The table below prints each condition verbatim.
Edges say which side they own. Each band edge is either “≤” (the exact value belongs to the lower band) or “<” (it belongs to the upper band), so no value lands in two bands. See the band-edge legend below.
Bands tile the axis. For RAP, PCWP, cardiac index, SvO₂, SVR, mean PA pressure, cardiac power and Qp:Qs, the bands cover every value from −∞ to +∞ (verified by a test), so no entered value is left uninterpreted. The criteria text on every finding is generated from the same condition the engine evaluates.
Every rule has a kind. Reference range, diagnostic definition, prognostic cutoff, population-specific finding, teaching framework or descriptive pattern. A prognostic or population-specific cutoff is never presented as a normal range.
Every rule cites a source. Citations are chips that link to the reference list below; the rule also records the population the threshold came from and any caveats about the evidence.
Missing data is reported, not guessed. If a rule cannot be evaluated (for example PVR without a cardiac output), the engine says which input is missing instead of defaulting.
Review status. All rules start as drafts pending clinical review and are marked as such; 0 of 54 are currently marked reviewed. The rule table version is 2026.10-r1-draft and is stamped on every interpretation.

Reference range vs diagnostic criterion vs prognostic cutoff vs population-specific finding vs teaching framework vs descriptive pattern

A threshold in this app is always one of six kinds. The same metric can carry several kinds at once, and the numbers are easy to confuse: a value on the favorable side of a prognostic cutoff is not “normal”, and a classification line is not a reference range. Every rule and every row of the range tables below is tagged with its kind.

Reference range
Where most healthy people fall. Not a disease statement and not a treatment threshold.
Cardiac index 2.5–4.0 L/min/m² is the reference range: where most healthy adults fall. Being outside it is not by itself a diagnosis.
Source:Naderi 2024
Diagnostic definition
A guideline definition (for example, how pulmonary hypertension is classified).
Mean PCWP ≤15 mmHg is the cutoff that classifies a pulmonary hypertension as pre-capillary (together with mPAP >20 and PVR >2 WU). It is a classification line, not a statement that a wedge of 14 is ideal.
Source:ESC/ERS 2022
Prognostic cutoff
An outcome cutoff from a derivation cohort. Being on the favorable side does not make a value normal.
Cardiac power output 0.6 W separated survivors from non-survivors in cardiogenic shock. It is a prognostic cutoff, not a normal range: resting CPO in health is about 1 W.
Source:Fincke 2004
Population-specific
Derived and valid only in the named population; it should not be applied to everyone.
PAPi 0.9 comes from patients with acute inferior MI and PAPi 1.85 from pre-LVAD patients. Each is valid only in its own cohort and is not a general cutoff.
Source:Korabathina 2012 Morine 2016
Teaching framework
A teaching scheme that uses numeric proxies (for example warm/cold, wet/dry). It does not replace clinical assessment.
Mean PCWP >18 mmHg and CI <2.2 are the “wet” and “cold” lines of the Forrester scheme. They are teaching proxies for congestion and hypoperfusion, and 18 is a different line from the PH classification cutoff of 15.
Source:Forrester 1976 SCAI 2022
Descriptive pattern
A description of findings occurring together, not a diagnosis.
RAP, PADP and PCWP close together (equalized diastolic pressures) describes findings that occur together, which has several causes. It is a pattern to recognize, not a diagnosis.
Source:Kern 2022

PCWP 15 vs 18: ≤15 is the PH-classification cutoff (diagnostic); 18 is Forrester’s congestion line (framework).
CI 2.5 vs 2.2: 2.5–4.0 is the reference range; 2.2 is the low-output cutoff used in shock and Forrester classification.
CPO 0.6 W: a prognostic cutoff from cardiogenic shock. A CPO above it is not a normal CPO.
PAPi 0.9, 1.85 and 2: 0.9 and 1.85 are cohort-specific (inferior MI, pre-LVAD); the app does not offer a universal PAPi cutoff.

Reference ranges and look-alike thresholds

21 metrics

One row per source, exactly as transcribed, tagged with its kind. Within each metric the true reference ranges come first; diagnostic, prognostic, population-specific and framework values for the same metric sit in a separate block, because they answer a different question. The last row is the band Swanology uses, and states which kind it is. A metric is flagged when the reference ranges’ limits differ by more than about 15% or when the chosen range itself notes a conflict; the disagreeing values are highlighted.

Right atrial pressure (mean) (mmHg)

Authors disagree

Source	Kind	Low	High	Mean	Note
Reference ranges
Kern 2022	Reference range	1	5	3
Naderi 2024	Reference range	2	6
Foucha 2009	Reference range	2	5
Bootsma 2022	Reference range	0	10		ICU range, supine, spontaneous breathing
Swanology uses	Reference range	2	6		Kern and Naderi agree on ~2–6; Bootsma's 0–10 is an ICU operating range rather than a normal.

Lower limit of the reference ranges runs from 0 (Bootsma 2022) to 2 (Naderi 2024). Upper limit of the reference ranges runs from 5 (Kern 2022) to 10 (Bootsma 2022).

RA a wave (mmHg)

Authors disagree

Source	Kind	Low	High	Mean	Note
Reference ranges
Kern 2022	Reference range	2	7	6
Foucha 2009	Reference range	2.5	7
Swanology uses	Reference range	2	7		Kern Table 22.2.

Lower limit of the reference ranges runs from 2 (Kern 2022) to 2.5 (Foucha 2009).

RA v wave (mmHg)

Source	Kind	Low	High	Mean	Note
Reference ranges
Kern 2022	Reference range	2	7	5
Foucha 2009	Reference range	2	7.5
Swanology uses	Reference range	2	7		Kern Table 22.2. In the RA the a wave is usually ≥ the v wave; in the LA the v wave dominates.

RV systolic (mmHg)

Source	Kind	Low	High	Mean	Note
Reference ranges
Kern 2022	Reference range	15	30	25
Naderi 2024	Reference range	15	30
Bootsma 2022	Reference range	15	28
Swanology uses	Reference range	15	30		All sources agree.

RV end-diastolic (mmHg)

Authors disagree

Source	Kind	Low	High	Mean	Note
Reference ranges
Kern 2022	Reference range	1	7	4
Naderi 2024	Reference range	2	8
Bootsma 2022	Reference range				near zero; diastolic slope horizontal
Swanology uses	Reference range	1	8		Union of Kern and Naderi.

Lower limit of the reference ranges runs from 1 (Kern 2022) to 2 (Naderi 2024).

PA systolic (mmHg)

Source	Kind	Low	High	Mean	Note
Reference ranges
Kern 2022	Reference range	15	30	25
Naderi 2024	Reference range	15	30
Bootsma 2022	Reference range	14	28
Swanology uses	Reference range	15	30		All sources agree.

PA diastolic (mmHg)

Authors disagree

Source	Kind	Low	High	Mean	Note
Reference ranges
Kern 2022	Reference range	4	12	9
Naderi 2024	Reference range	8	15
Bootsma 2022	Reference range	5	16
Swanology uses	Reference range	4	12		Kern. Naderi and Bootsma allow up to 15–16; PADP ≈ PCWP when PVR is normal.

Lower limit of the reference ranges runs from 4 (Kern 2022) to 8 (Naderi 2024). Upper limit of the reference ranges runs from 12 (Kern 2022) to 16 (Bootsma 2022).

PA mean (mmHg)

Authors disagree

Source	Kind	Low	High	Mean	Note
Reference ranges
Kern 2022	Reference range	9	19	15
Naderi 2024	Reference range	9	18
Bootsma 2022	Reference range	10	22
Kovacs 2009	Reference range			14	14 ± 3; upper limit of normal ≈ 20
Other thresholds that are often mistaken for rangesDiagnostic, prognostic, population-specific or framework values for the same metric. They answer a different question from “what is normal?”.
ESC/ERS 2022	Diagnostic definition		20		PH defined as mPAP >20
Swanology uses	Diagnostic definition		20		This is a diagnostic definition, not a reference range. A guideline definition (for example, how pulmonary hypertension is classified).ESC/ERS 2022 definition; Bootsma's 22 predates it.

Upper limit of the reference ranges runs from 18 (Naderi 2024) to 22 (Bootsma 2022).

PCWP (mean) (mmHg)

Authors disagree

Source	Kind	Low	High	Mean	Note
Reference ranges
Kern 2022	Reference range	4	12	9
Naderi 2024	Reference range	6	12
Bootsma 2022	Reference range	5	12
Foucha 2009	Reference range	4.5	13
Other thresholds that are often mistaken for rangesDiagnostic, prognostic, population-specific or framework values for the same metric. They answer a different question from “what is normal?”.
ESC/ERS 2022	Diagnostic definition		15		≤15 counts as 'normal' for PH classification
HFA-PEFF 2019	Diagnostic definition	15			resting PCWP ≥15 is a major HFpEF criterion
Swanology uses	Reference range	5	12		Textbook normal 5–12; 13–15 is treated as upper-normal because the PH and HFpEF criteria meet there.

Lower limit of the reference ranges runs from 4 (Kern 2022) to 6 (Naderi 2024).

LA mean (mmHg)

Authors disagree

Source	Kind	Low	High	Mean	Note
Reference ranges
Kern 2022	Reference range	2	12	8
Naderi 2024	Reference range	4	12
Foucha 2009	Reference range	2	12
Swanology uses	Reference range	2	12		Kern.

Lower limit of the reference ranges runs from 2 (Kern 2022) to 4 (Naderi 2024).

Aortic / arterial mean (mmHg)

Source	Kind	Low	High	Mean	Note
Reference ranges
Kern 2022	Reference range	70	105	85
Naderi 2024	Reference range	70	105
Swanology uses	Reference range	70	105		Sources agree.

Cardiac index (L/min/m²)

Source	Kind	Low	High	Note
Reference ranges
Naderi 2024	Reference range	2.5	4
Other thresholds that are often mistaken for rangesDiagnostic, prognostic, population-specific or framework values for the same metric. They answer a different question from “what is normal?”.
Forrester 1976	Teaching framework	2.2		hypoperfusion threshold <2.2
SCAI 2022	Teaching framework	2.2		cardiogenic shock hemodynamic criterion CI <2.2
Swanology uses	Reference range	2.5	4	Naderi; 2.2 is the shock threshold, not the lower limit of normal.

Stroke volume (mL/beat)

Source	Kind	Low	High	Note
Reference ranges
Naderi 2024	Reference range	60	100	'average 70' in the text
Swanology uses	Reference range	60	100	Naderi.

Mixed venous O₂ saturation (%)

Source	Kind	Low	High	Note
Reference ranges
Naderi 2024	Reference range	60	80
Kern 2022	Reference range		80	PA saturation >80% suggests a left-to-right shunt
Other thresholds that are often mistaken for rangesDiagnostic, prognostic, population-specific or framework values for the same metric. They answer a different question from “what is normal?”.
ESC/ERS 2022	Prognostic cutoff	65		PAH risk table: >65% low risk; 60–65 intermediate; <60 high risk (prognostic, not a reference range)
Swanology uses	Reference range	60	80	Naderi's reference range. The ESC/ERS 65/60 thresholds are PAH prognostic cutoffs, not a reference range; Kern's 80% is a shunt-screening threshold.

Systemic vascular resistance (dyn·s·cm⁻⁵)

Authors disagree

Source	Kind	Low	High	Mean	Note
Reference ranges
Naderi 2024	Reference range	800	1200		table; the text says 900–1440
Kern 2022	Reference range	700	1600	1100
Swanology uses	Reference range	800	1400		Between Naderi's table (800–1200) and Kern (700–1600); a healthy adult with MAP 90, RAP 4, CO 5.2 has SVR ≈1320. Authors disagree.

Upper limit of the reference ranges runs from 1200 (Naderi 2024) to 1600 (Kern 2022).

Pulmonary vascular resistance (WU)

Authors disagree

Source	Kind	Low	High	Mean	Note
Reference ranges
Kern 2022	Reference range	0.25	1.63	0.88	20–130 dyn (0.25–1.6 WU)
Naderi 2024	Reference range		2		<2 WU in the text; table says <250 dyn (3.1 WU)
Other thresholds that are often mistaken for rangesDiagnostic, prognostic, population-specific or framework values for the same metric. They answer a different question from “what is normal?”.
ESC/ERS 2022	Diagnostic definition		2		>2 WU defines the pre-capillary component
WSPH 2018	Diagnostic definition		3		≥3 WU (superseded)
Swanology uses	Diagnostic definition		2		This is a diagnostic definition, not a reference range. A guideline definition (for example, how pulmonary hypertension is classified).ESC/ERS 2022. Naderi's own table and text disagree with each other (250 dyn vs 2 WU).

Upper limit of the reference ranges runs from 1.63 (Kern 2022) to 2 (Naderi 2024).

Transpulmonary gradient (mmHg)

Source	Kind	High	Note
Reference ranges
Naderi 2024	Reference range	12	older teaching: TPG >12 suggests a pre-capillary component
Other thresholds that are often mistaken for rangesDiagnostic, prognostic, population-specific or framework values for the same metric. They answer a different question from “what is normal?”.
ISHLT 2016	Population-specific	16	>16 is a transplant relative contraindication; ≥15 triggers vasodilator testing
Swanology uses	Diagnostic definition	12	This is a diagnostic definition, not a reference range. A guideline definition (for example, how pulmonary hypertension is classified).Supportive only; PVR is preferred by current guidelines.

Diastolic pulmonary gradient (mmHg)

Source	Kind	High	Note
Reference ranges
No source here gives a reference range for this metric. The values below are not normal ranges.
Other thresholds that are often mistaken for rangesDiagnostic, prognostic, population-specific or framework values for the same metric. They answer a different question from “what is normal?”.
Vachiéry 2013	Diagnostic definition	7	≥7 proposed for a pre-capillary component in left-heart PH
Swanology uses	Diagnostic definition	7	This is a diagnostic definition, not a reference range. A guideline definition (for example, how pulmonary hypertension is classified).Historical; superseded by PVR.

PA pulsatility index

Source	Kind	Low	Note
Reference ranges
No source here gives a reference range for this metric. The values below are not normal ranges.
Other thresholds that are often mistaken for rangesDiagnostic, prognostic, population-specific or framework values for the same metric. They answer a different question from “what is normal?”.
Korabathina 2012	Population-specific	0.9	≤0.9 severe RV dysfunction in acute inferior MI
Morine 2016	Population-specific	1.85	<1.85 RV failure after LVAD
Swanology uses	Population-specific	2	This is a population-specific, not a reference range. Derived and valid only in the named population; it should not be applied to everyone.No universal cutoff; cohort-specific thresholds of 0.9 and 1.85.

RAP : PCWP ratio

Source	Kind	High	Note
Reference ranges
No source here gives a reference range for this metric. The values below are not normal ranges.
Other thresholds that are often mistaken for rangesDiagnostic, prognostic, population-specific or framework values for the same metric. They answer a different question from “what is normal?”.
Kormos 2010	Population-specific	0.63	>0.63 predicts RV failure after LVAD
Lala 2018	Population-specific		SHOCK analysis used elevated CVP, CVP/PCWP, PAPi and RVSWI to define RV dysfunction; the specific cutoffs were not verified here
Swanology uses	Population-specific	0.63	This is a population-specific, not a reference range. Derived and valid only in the named population; it should not be applied to everyone.No universal cutoff. 0.63 is the pre-LVAD cohort value (Kormos); normal RA:PCWP is roughly 0.3–0.6.

Cardiac power output (W)

Source	Kind	Low	Note
Reference ranges
No source here gives a reference range for this metric. The values below are not normal ranges.
Other thresholds that are often mistaken for rangesDiagnostic, prognostic, population-specific or framework values for the same metric. They answer a different question from “what is normal?”.
Fincke 2004	Prognostic cutoff	0.6	<0.6 W (derivation 0.53) predicted mortality in cardiogenic shock; this is a prognostic cutoff, not a reference range; resting normal ≈1 W
Swanology uses	Prognostic cutoff	0.6	This is a prognostic cutoff, not a reference range. An outcome cutoff from a derivation cohort. Being on the favorable side does not make a value normal.SHOCK registry.

Band edges

8 band sets

Rules that share a band set divide one metric’s axis between them: every value lands in exactly one band. In the edge strings below, a leading < means the exact edge value belongs to the upper band, and a leading ≤ means it belongs to the lower band. The conditions are generated from the same definitions the engine evaluates.

RAP edges: <2 | ≤6 | ≤10 | ≤15

Exact edge values: 2: in the upper band (band 2); 6: in the lower band (band 2); 10: in the lower band (band 3); 15: in the lower band (band 4).

Band	Condition	Rule
1	RAP < 2 mmHg	rap-low
2	2 ≤ RAP ≤ 6 mmHg	rap-normal
3	6 < RAP ≤ 10 mmHg	rap-mild
4	10 < RAP ≤ 15 mmHg	rap-moderate
5	RAP > 15 mmHg	rap-severe

Mean PCWP edges: <5 | ≤12 | ≤15 | ≤18 | <25

Exact edge values: 5: in the upper band (band 2); 12: in the lower band (band 2); 15: in the lower band (band 3); 18: in the lower band (band 4); 25: in the upper band (band 6).

Band	Condition	Rule
1	mean PCWP < 5 mmHg	pcwp-low
2	5 ≤ mean PCWP ≤ 12 mmHg	pcwp-normal
3	12 < mean PCWP ≤ 15 mmHg	pcwp-borderline
4	15 < mean PCWP ≤ 18 mmHg	pcwp-elevated
5	18 < mean PCWP < 25 mmHg	pcwp-high
6	mean PCWP ≥ 25 mmHg	pcwp-severe

Cardiac index edges: <2 | <2.2 | <2.5 | ≤4

Exact edge values: 2: in the upper band (band 2); 2.2: in the upper band (band 3); 2.5: in the upper band (band 4); 4: in the lower band (band 4).

Band	Condition	Rule
1	cardiac index < 2 L/min/m²	ci-severely-reduced
2	2 ≤ cardiac index < 2.2 L/min/m²	ci-reduced
3	2.2 ≤ cardiac index < 2.5 L/min/m²	ci-low-normal
4	2.5 ≤ cardiac index ≤ 4 L/min/m²	ci-normal
5	cardiac index > 4 L/min/m²	ci-high

SvO₂ edges: <50 | <60 | ≤80

Exact edge values: 50: in the upper band (band 2); 60: in the upper band (band 3); 80: in the lower band (band 3).

Band	Condition	Rule
1	SvO₂ < 50 %	svo2-critical
2	50 ≤ SvO₂ < 60 %	svo2-low
3	60 ≤ SvO₂ ≤ 80 %	svo2-normal
4	SvO₂ > 80 %	svo2-high

SVR edges: <800 | <1400

Exact edge values: 800: in the upper band (band 2); 1400: in the upper band (band 3).

Band	Condition	Rule
1	SVR < 800 dyn·s·cm⁻⁵	svr-low
2	800 ≤ SVR < 1400 dyn·s·cm⁻⁵	svr-normal
3	SVR ≥ 1400 dyn·s·cm⁻⁵	svr-high

Mean PA pressure edges: ≤20

Exact edge values: 20: in the lower band (band 1).

Band	Condition	Rule
1	mean PA pressure ≤ 20 mmHg	ph-none
2	mean PA pressure > 20 mmHg	ph-present

Cardiac power edges: <0.6

Exact edge values: 0.6: in the upper band (band 2).

Band	Condition	Rule
1	cardiac power < 0.6 W	cpo-low
2	cardiac power ≥ 0.6 W	cpo-ok

Qp:Qs edges: <1 | <1.5 | ≤2

Exact edge values: 1: in the upper band (band 2); 1.5: in the upper band (band 3); 2: in the lower band (band 3).

Band	Condition	Rule
1	Qp:Qs < 1	qpqs-net-rl
2	1 ≤ Qp:Qs < 1.5	qpqs-small
3	1.5 ≤ Qp:Qs ≤ 2	qpqs-moderate
4	Qp:Qs > 2	qpqs-large

Rule table

54 rules · Draft — pending review 54

Threshold kind

Domain

Group by

54 rules

Right-sided filling · 6

rap-lowReference rangelowDraft — pending review
Low right atrial pressure
when RAP < 2 mmHg
Band set: RAP · band 1 of 5 · edges <2 | ≤6 | ≤10 | ≤15
Suggests reduced venous return (hypovolemia or venodilation), or a transducer/zero problem. A low RAP does not by itself predict that stroke volume will rise with fluid; CVP correlates poorly with fluid responsiveness.
Cites:Kern 2022 Marik 2013 Damrongwatanasuk 2026
rap-normalReference rangenormalDraft — pending review
Right atrial pressure within the reference range
when 2 ≤ RAP ≤ 6 mmHg
Band set: RAP · band 2 of 5 · edges <2 | ≤6 | ≤10 | ≤15
Kern gives a mean RAP of 3 mmHg (range 1–5); Naderi 2–6. ICU references quote up to 10, which includes many congested patients.
Cites:Kern 2022 Naderi 2024 Bootsma 2022
rap-mildReference rangehighDraft — pending review
Mildly elevated right atrial pressure
when 6 < RAP ≤ 10 mmHg
Band set: RAP · band 3 of 5 · edges <2 | ≤6 | ≤10 | ≤15
Above the textbook range. In the PH risk tables an RAP of 8–14 falls in the intermediate-risk band (a prognostic table for patients with PAH, not a reference range).
Cites:Kern 2022 ESC/ERS 2022
rap-moderateReference rangehighDraft — pending review
Moderately elevated right atrial pressure
when 10 < RAP ≤ 15 mmHg
Band set: RAP · band 4 of 5 · edges <2 | ≤6 | ≤10 | ≤15
Indicates systemic venous congestion. In decompensated heart failure, venous congestion (not low cardiac index) was the strongest hemodynamic predictor of worsening renal function in one cohort.
Cites:Mullens 2009 Hsu 2022
rap-severeReference rangealertDraft — pending review
Markedly elevated right atrial pressure
when RAP > 15 mmHg
Band set: RAP · band 5 of 5 · edges <2 | ≤6 | ≤10 | ≤15
Severe venous congestion. Think RV failure, pericardial disease (tamponade, constriction), severe tricuspid disease, or volume overload. In the PH risk table an RAP above 14 is the high-risk band (PAH-specific). Look at the waveform: the x and y descents help separate tamponade, constriction, and restriction.
Cites:Mullens 2009 ESC/ERS 2022 Damrongwatanasuk 2026
equalized-diastolicsDescriptive patternhighDraft — pending review
Not a reference range. A description of findings occurring together, not a diagnosis.
Equalized diastolic pressures (RAP ≈ PADP ≈ PCWP)
when RAP ≥ 10 mmHg and PCWP − RAP ≥ -5 mmHg and PCWP − RAP ≤ 5 mmHg and DPG ≥ -5 mmHg and DPG ≤ 5 mmHg
RAP, PA diastolic and wedge are all within about 5 mmHg of each other at an elevated level. This is the pattern of pericardial constraint (tamponade, constriction) or a stiff, failing RV; the waveform separates them: tamponade blunts the y descent, constriction has brisk x and y descents, RV failure keeps the y. Look for pulsus paradoxus and respiratory ventricular interdependence. A PH classification computed from these pressures describes the numbers only: with pericardial constraint an elevated wedge reflects the constraint, not necessarily left-heart disease.
Cites:Kern 2022 Naderi 2024 Damrongwatanasuk 2026

Left-sided filling · 6

pcwp-lowReference rangelowDraft — pending review
Low wedge pressure
when mean PCWP < 5 mmHg
Band set: Mean PCWP · band 1 of 6 · edges <5 | ≤12 | ≤15 | ≤18 | <25
Can reflect genuinely low left-sided filling (hypovolemia, vasodilation), but a falsely low wedge is usually a measurement problem: transducer above the phlebostatic axis, an over-damped line (air, clot, kink), or reading at the wrong point of the respiratory cycle. Confirm the zero, the level, the damping and the waveform before acting on a low value. (Incomplete occlusion does the opposite: it mixes in pulmonary artery pressure and reads falsely high.)
Cites:Kern 2022 Naderi 2024 Bootsma 2022
pcwp-normalReference rangenormalDraft — pending review
Mean wedge pressure within the reference range
when 5 ≤ mean PCWP ≤ 12 mmHg
Band set: Mean PCWP · band 2 of 6 · edges <5 | ≤12 | ≤15 | ≤18 | <25
Kern: mean PCWP 9 (range 4–12); Naderi 6–12; Bootsma 5–12. These are cardiac-cycle mean values.
Cites:Kern 2022 Naderi 2024 Bootsma 2022
pcwp-borderlineReference rangeinfoDraft — pending review
Mean wedge pressure above the reference range but not above 15
when 12 < mean PCWP ≤ 15 mmHg
Band set: Mean PCWP · band 3 of 6 · edges <5 | ≤12 | ≤15 | ≤18 | <25
Above the usual reference range, but not above the 15 mmHg cutoff that classifies a wedge as post-capillary in PH. A resting PCWP of 15 or more is also a functional criterion in the HFA-PEFF algorithm. When the clinical question is unexplained dyspnea, this is where exercise or fluid challenge can add the most.
Cites:ESC/ERS 2022 HFA-PEFF 2019 Borlaug 2010
pcwp-elevatedDiagnostic definitionhighDraft — pending review
Not a reference range. A guideline definition (for example, how pulmonary hypertension is classified).
Mean wedge pressure above 15 mmHg (post-capillary range)
when 15 < mean PCWP ≤ 18 mmHg
Band set: Mean PCWP · band 4 of 6 · edges <5 | ≤12 | ≤15 | ≤18 | <25
Above the 15 mmHg cutoff used to classify PH as post-capillary. It is at or below the 18 mmHg threshold that Forrester used for pulmonary congestion in acute MI. These are different frameworks with different purposes, which is why a study can meet the post-capillary PH criterion and still sit in the 'dry' box of the warm/cold, wet/dry teaching grid.
Cites:ESC/ERS 2022 Forrester 1976 Kern 2022
pcwp-highTeaching frameworkhighDraft — pending review
Not a reference range. A teaching scheme that uses numeric proxies (for example warm/cold, wet/dry). It does not replace clinical assessment.
Mean wedge pressure above 18 mmHg
when 18 < mean PCWP < 25 mmHg
Band set: Mean PCWP · band 5 of 6 · edges <5 | ≤12 | ≤15 | ≤18 | <25
Above the Forrester threshold for pulmonary congestion. Consider whether a large v wave (for example mitral regurgitation) is inflating the cardiac-cycle mean; compare with the end-diastolic wedge, which is closer to LVEDP.
Cites:Forrester 1976 Kern 2022
pcwp-severeTeaching frameworkalertDraft — pending review
Not a reference range. A teaching scheme that uses numeric proxies (for example warm/cold, wet/dry). It does not replace clinical assessment.
Severely elevated mean wedge pressure
when mean PCWP ≥ 25 mmHg
Band set: Mean PCWP · band 6 of 6 · edges <5 | ≤12 | ≤15 | ≤18 | <25
Hydrostatic pulmonary edema is likely at this level unless chronic adaptation has raised the threshold. Note that 25 mmHg is also the cutoff used for exercise wedge pressure in HFpEF testing; that is a peak-exercise criterion, not a resting one.
Cites:Forrester 1976 Borlaug 2010

Cardiac output · 5

ci-low-normalReference rangeinfoDraft — pending review
Cardiac index below the reference range but above the low-output cutoff
when 2.2 ≤ cardiac index < 2.5 L/min/m²
Band set: Cardiac index · band 3 of 5 · edges <2 | <2.2 | <2.5 | ≤4
Below the usual reference range of 2.5–4.0 L/min/m², yet above the 2.2 cutoff used for 'cold' in shock frameworks. Those two numbers answer different questions (what is typical versus what flags low output); a CI above 2.2 does not by itself establish adequate tissue perfusion.
Cites:Naderi 2024 Forrester 1976
ci-normalReference rangenormalDraft — pending review
Cardiac index within the reference range
when 2.5 ≤ cardiac index ≤ 4 L/min/m²
Band set: Cardiac index · band 4 of 5 · edges <2 | <2.2 | <2.5 | ≤4
Naderi's reference range is 2.5–4.0 L/min/m². A CI in range does not establish adequate tissue perfusion: a normal index with low MAP still gives a low cardiac power, and perfusion is judged clinically (lactate, mentation, urine output) and with SvO₂.
Cites:Naderi 2024 Kern 2022
ci-highReference rangehighDraft — pending review
High cardiac index
when cardiac index > 4 L/min/m²
Band set: Cardiac index · band 5 of 5 · edges <2 | <2.2 | <2.5 | ≤4
Suggests a high-output state: sepsis/vasodilation, anemia, thyrotoxicosis, cirrhosis, AV fistula, or a left-to-right shunt (check for a PA saturation step-up). If the output came from estimated (assumed-VO₂) Fick, remember that cardiac output = VO₂ ÷ (arterial − venous O₂ content). For the same oxygen contents, an assumed VO₂ that is too HIGH overestimates the calculated output, and one that is too low underestimates it.
Cites:Naderi 2024 Kern 2022
ci-severely-reducedTeaching frameworkalertDraft — pending review
Not a reference range. A teaching scheme that uses numeric proxies (for example warm/cold, wet/dry). It does not replace clinical assessment.
Severely reduced cardiac index
when cardiac index < 2 L/min/m²
Band set: Cardiac index · band 1 of 5 · edges <2 | <2.2 | <2.5 | ≤4
Low output alone does not define shock; shock requires evidence of hypoperfusion (lactate, mentation, urine output). Check SvO₂ and cardiac power to judge adequacy, and check which cardiac-output method produced the number.
Cites:SCAI 2022 Forrester 1976
ci-reducedTeaching frameworkhighDraft — pending review
Not a reference range. A teaching scheme that uses numeric proxies (for example warm/cold, wet/dry). It does not replace clinical assessment.
Reduced cardiac index (below the 2.2 low-output cutoff)
when 2 ≤ cardiac index < 2.2 L/min/m²
Band set: Cardiac index · band 2 of 5 · edges <2 | <2.2 | <2.5 | ≤4
Below the 2.2 L/min/m² threshold used in the Forrester subsets and in cardiogenic shock definitions. A numerical cutoff, not a perfusion diagnosis.
Cites:Forrester 1976 SCAI 2022

Oxygen delivery · 6

svo2-criticalReference rangealertDraft — pending review
Very low mixed venous saturation
when SvO₂ < 50 %
Band set: SvO₂ · band 1 of 4 · edges <50 | <60 | ≤80
Oxygen extraction is high relative to delivery. Delivery depends on cardiac output, hemoglobin and arterial saturation; demand depends on metabolic rate (fever, shivering, work of breathing). Read it with all of these and with clinical perfusion; it is a flag to investigate, not a diagnosis.
Cites:Naderi 2024 Hsu 2022
svo2-lowReference rangehighDraft — pending review
Low mixed venous saturation
when 50 ≤ SvO₂ < 60 %
Band set: SvO₂ · band 2 of 4 · edges <50 | <60 | ≤80
Delivery is low relative to consumption or demand is high: low output, anemia, hypoxemia, or a hypermetabolic state. Interpret with hemoglobin, SaO₂, cardiac output and metabolic demand, not in isolation.
Cites:Naderi 2024 Hsu 2022
svo2-normalReference rangenormalDraft — pending review
Mixed venous saturation within the reference range
when 60 ≤ SvO₂ ≤ 80 %
Band set: SvO₂ · band 3 of 4 · edges <50 | <60 | ≤80
Naderi gives 60–80%. A value in range does not prove that oxygen delivery is adequate for demand: with impaired extraction or microcirculatory shunting (classically sepsis) SvO₂ can be normal or high despite tissue hypoxia. Read it with hemoglobin, arterial saturation, cardiac output, metabolic demand, lactate and the clinical exam.
Cites:Naderi 2024 Hsu 2022
svo2-highReference rangehighDraft — pending review
High mixed venous saturation
when SvO₂ > 80 %
Band set: SvO₂ · band 4 of 4 · edges <50 | <60 | ≤80
Suggests a left-to-right shunt (pulmonary venous blood mixing in), a wedged sample, a high-output state, or impaired tissue extraction (sepsis, for example). Kern: a PA saturation above 80% should prompt a saturation run to look for a step-up. A high SvO₂ is not reassurance about tissue oxygenation.
Cites:Kern 2022
svo2-pah-intermediatePrognostic cutoffinfoDraft — pending review
Not a reference range. An outcome cutoff from a derivation cohort. Being on the favorable side does not make a value normal.
SvO₂ in the intermediate-risk band of the PAH risk table
when mean PA pressure > 20 mmHg and mean PCWP ≤ 15 mmHg and PVR > 2 WU and SvO₂ ≥ 60 % and SvO₂ ≤ 65 %
In established PAH, the ESC/ERS risk table places SvO₂ of 60–65% in the intermediate-risk band (above 65% low risk, below 60% high risk). These are prognostic thresholds for patients with PAH on follow-up, not a general reference range.
Population
Established PAH (ESC/ERS 2022 risk table)
Cites:ESC/ERS 2022
svo2-pah-high-riskPrognostic cutoffalertDraft — pending review
Not a reference range. An outcome cutoff from a derivation cohort. Being on the favorable side does not make a value normal.
SvO₂ below the high-risk threshold of the PAH risk table
when mean PA pressure > 20 mmHg and mean PCWP ≤ 15 mmHg and PVR > 2 WU and SvO₂ < 60 %
In established PAH, an SvO₂ below 60% sits in the high-risk band of the ESC/ERS risk table. It is a prognostic marker in patients with PAH, not a general statement about oxygen delivery in other conditions.
Population
Established PAH (ESC/ERS 2022 risk table)
Cites:ESC/ERS 2022

Pulmonary circulation · 13

ph-noneDiagnostic definitionnormalDraft — pending review
Not a reference range. A guideline definition (for example, how pulmonary hypertension is classified).
Mean PA pressure not above 20 mmHg
when mean PA pressure ≤ 20 mmHg
Band set: Mean PA pressure · band 1 of 2 · edges ≤20
The upper limit of normal for resting mean PA pressure is about 20 mmHg (normal mean 14 ± 3).
Cites:ESC/ERS 2022 Kovacs 2009
ph-presentDiagnostic definitionhighDraft — pending review
Not a reference range. A guideline definition (for example, how pulmonary hypertension is classified).
Pulmonary hypertension by the resting mPAP definition
when mean PA pressure > 20 mmHg
Band set: Mean PA pressure · band 2 of 2 · edges ≤20
By the 2022 ESC/ERS definition, PH is a resting mean PA pressure above 20 mmHg. The mean wedge pressure and PVR then classify it as pre-capillary, post-capillary, or combined.
Cites:ESC/ERS 2022
ph-mild-rangeDiagnostic definitioninfoDraft — pending review
Not a reference range. A guideline definition (for example, how pulmonary hypertension is classified).
mPAP between 20 and 25 mmHg: meets the current definition, 'borderline' under older ones
when 20 < mean PA pressure < 25 mmHg
Before 2018 the PH threshold was mPAP of 25 or more and the 21–24 range was called borderline. A mildly elevated mPAP still carries prognostic weight, which motivated the change.
Cites:WSPH 2018 ESC/ERS 2022
ph-precapillaryDiagnostic definitionalertDraft — pending review
Not a reference range. A guideline definition (for example, how pulmonary hypertension is classified).
Pre-capillary pulmonary hypertension
when mean PA pressure > 20 mmHg and mean PCWP ≤ 15 mmHg and PVR > 2 WU
The hemodynamic definition: mPAP above 20, mean PAWP 15 or less, PVR above 2 WU. This describes the pressures and resistance; it does not by itself identify the cause (groups 1, 3, 4, 5 are distinguished clinically).
Cites:ESC/ERS 2022
ph-ipcDiagnostic definitionhighDraft — pending review
Not a reference range. A guideline definition (for example, how pulmonary hypertension is classified).
Isolated post-capillary pulmonary hypertension
when mean PA pressure > 20 mmHg and mean PCWP > 15 mmHg and PVR ≤ 2 WU
The hemodynamic definition: mPAP above 20, mean PAWP above 15, and PVR 2 WU or less. By this definition the PVR is not elevated; the pulmonary pressure is explained by the left-sided filling pressure. A PVR threshold alone cannot establish that the pulmonary vasculature is structurally normal.
Cites:ESC/ERS 2022
ph-cpcDiagnostic definitionalertDraft — pending review
Not a reference range. A guideline definition (for example, how pulmonary hypertension is classified).
Combined pre- and post-capillary pulmonary hypertension
when mean PA pressure > 20 mmHg and mean PCWP > 15 mmHg and PVR > 2 WU
The hemodynamic definition: mPAP above 20, mean PAWP above 15, PVR above 2 WU. Left-sided pressure is elevated and the PVR is also elevated. A vasodilator or fluid challenge can help decide how much of the PVR elevation is reversible.
Cites:ESC/ERS 2022
ph-unclassifiedDiagnostic definitioninfoDraft — pending review
Not a reference range. A guideline definition (for example, how pulmonary hypertension is classified).
Pulmonary hypertension with normal PVR and wedge
when mean PA pressure > 20 mmHg and mean PCWP ≤ 15 mmHg and PVR ≤ 2 WU
mPAP above 20 with mean PAWP 15 or less and PVR 2 WU or less: the pressure rise is explained by high flow rather than resistance. Think left-to-right shunt, anemia, cirrhosis, thyrotoxicosis, or a high-output state.
Cites:ESC/ERS 2022 Naderi 2024
pvr-gray-zoneDiagnostic definitioninfoDraft — pending review
Not a reference range. A guideline definition (for example, how pulmonary hypertension is classified).
PVR between 2 and 3 WU: pre-capillary by 2022 criteria, not by 2018 criteria
when mean PA pressure > 20 mmHg and PVR > 2 WU and PVR < 3 WU
The 2022 ESC/ERS guideline lowered the PVR threshold from 3 WU or more to above 2 WU. Values in between are classified differently by the two definitions; the library chapters (Naderi, Kern) still use 3.
Evidence
Sources disagree: 2 WU (ESC/ERS 2022) vs 3 WU (WSPH 2018, Naderi, Kern).
Cites:ESC/ERS 2022 WSPH 2018 Naderi 2024
dpg-precap-componentDiagnostic definitioninfoDraft — pending review
Not a reference range. A guideline definition (for example, how pulmonary hypertension is classified).
DPG of 7 or more supports a pre-capillary component
when mean PA pressure > 20 mmHg and mean PCWP > 15 mmHg and DPG ≥ 7 mmHg
A diastolic pulmonary gradient (PADP − mean PCWP) of 7 mmHg or more was proposed in 2013 to identify a pre-capillary component in left-heart PH. PVR is now preferred because DPG is noisy, but a high DPG still points the same way.
Evidence
Historical criterion; superseded by PVR in guidelines.
Cites:Vachiéry 2013 ESC/ERS 2022
tx-challenge-triggerPopulation-specifichighDraft — pending review
Not a reference range. Derived and valid only in the named population; it should not be applied to everyone.
Meets the combination that prompts a vasodilator challenge in transplant evaluation
when transplant evaluation and PA systolic ≥ 50 mmHg and (TPG ≥ 15 mmHg or PVR ≥ 3 WU)
The 2024 ISHLT candidate guideline is summarized (from secondary sources; confirm against the full text) as using PASP of 50 mmHg or more with a TPG of 15 mmHg or more or a PVR of 3 WU or more to prompt a stepwise evaluation while keeping systolic pressure above 85 mmHg: an acute vasodilator challenge to test reversibility, then, if unsatisfactory, monitored inpatient vasoactive therapy, and then consideration of mechanical circulatory support to unload the LV. This is a trigger for further testing, not a determination of eligibility: risk rises along a continuum and candidacy is a transplant-team decision. Agents, doses and stopping rules are local protocol.
Population
Heart transplant candidates
Evidence
Summarized from secondary sources; not yet verified against the full 2024 ISHLT text.
Cites:ISHLT 2024
pvr-high-no-phDescriptive patterninfoDraft — pending review
Not a reference range. A description of findings occurring together, not a diagnosis.
Elevated PVR without pulmonary hypertension
when mean PA pressure ≤ 20 mmHg and PVR > 2 WU
PVR above 2 WU with mPAP not above 20. Low cardiac output inflates PVR arithmetically (same gradient, less flow), so interpret with the cardiac output and its method.
Cites:ESC/ERS 2022
pvr-low-flowDescriptive patterninfoDraft — pending review
Not a reference range. A description of findings occurring together, not a diagnosis.
PVR is inflated by low cardiac output
when PVR > 2 WU and pulmonaryFlow < 3
PVR = (mPAP − mean PCWP) / flow, so the same transpulmonary gradient ({{tpg}} mmHg) gives a higher resistance when flow is low ({{pulmonaryFlow}} L/min). Before calling the vasculature remodeled, look at the gradient itself and at what happens to PVR when output is restored.
Cites:ESC/ERS 2022 Hsu 2022
pvr-severeDescriptive patternhighDraft — pending review
Not a reference range. A description of findings occurring together, not a diagnosis.
Severely elevated PVR (above 5 WU)
when not transplant evaluation and PVR > 5 WU
A PVR above 5 WU is a marked elevation. Whether it is fixed or reversible is a separate question answered by vasodilator or inotrope challenge, and no single PVR value determines candidacy for any advanced therapy. Mark the study as a transplant evaluation to see the transplant-evaluation trigger.
Cites:ESC/ERS 2022

Right ventricle · 9

papi-imi-lowPopulation-specificalertDraft — pending review
Not a reference range. Derived and valid only in the named population; it should not be applied to everyone.
PAPi below 0.9 in acute inferior MI
when acute inferior MI and PAPi < 0.9
In the derivation cohort of acute inferior MI, a PAPi of 0.9 or less identified severe RV dysfunction and predicted in-hospital mortality and the need for RV support. The cutoff is specific to that population.
Population
Acute inferior MI (derivation cohort)
Cites:Korabathina 2012
papi-imi-okPopulation-specificinfoDraft — pending review
Not a reference range. Derived and valid only in the named population; it should not be applied to everyone.
PAPi at or above 0.9 in acute inferior MI
when acute inferior MI and PAPi ≥ 0.9
Above the derivation-cohort cutoff for severe RV dysfunction. This does not exclude RV dysfunction at a milder degree and is not a normal range.
Population
Acute inferior MI
Cites:Korabathina 2012
papi-lvad-lowPopulation-specificalertDraft — pending review
Not a reference range. Derived and valid only in the named population; it should not be applied to everyone.
PAPi below 1.85 before LVAD
when pre-LVAD evaluation and PAPi < 1.85
A pre-implant PAPi below 1.85 was associated with RV failure after LVAD surgery in one cohort. Other cohorts have proposed cutoffs near 2.
Population
Pre-LVAD evaluation
Cites:Morine 2016 Kang 2016
papi-lvad-okPopulation-specificinfoDraft — pending review
Not a reference range. Derived and valid only in the named population; it should not be applied to everyone.
PAPi at or above 1.85 before LVAD
when pre-LVAD evaluation and PAPi ≥ 1.85
Above the cohort cutoff associated with RV failure after implant. It does not exclude RV failure and is not a normal range.
Population
Pre-LVAD evaluation
Cites:Morine 2016
rapcwp-lvadPopulation-specifichighDraft — pending review
Not a reference range. Derived and valid only in the named population; it should not be applied to everyone.
RAP:PCWP above 0.63 before LVAD
when pre-LVAD evaluation and RAP:PCWP > 0.63
In the HeartMate II experience, RAP/PCWP above 0.63 was an independent predictor of RV failure after implant. The cutoff comes from that surgical population.
Population
Pre-LVAD evaluation
Cites:Kormos 2010
papi-general-lowDescriptive patternhighDraft — pending review
Not a reference range. A description of findings occurring together, not a diagnosis.
Low PAPi (below 2): small RV pulse pressure relative to RA pressure
when not acute inferior MI and not pre-LVAD evaluation and PAPi < 2
PAPi = (PASP − PADP)/RAP. There is no universal cutoff: 0.9 came from inferior MI and 1.85 from pre-LVAD cohorts. Outside those settings a PAPi below about 2 is a reasonable flag for RV dysfunction, especially with a high RAP. PAPi becomes unstable when RAP is very low.
Evidence
The cutoff of 2 is an extrapolation; the derivation cohorts used 0.9 (inferior MI) and 1.85 (pre-LVAD).
Cites:Korabathina 2012 Morine 2016 Hsu 2022
papi-general-okDescriptive patterninfoDraft — pending review
Not a reference range. A description of findings occurring together, not a diagnosis.
PAPi at or above 2
when not acute inferior MI and not pre-LVAD evaluation and PAPi ≥ 2
Above the cohort cutoffs for RV dysfunction. A PAPi in this range does not exclude RV dysfunction and is not a normal range; read it with the RAP, the RAP:PCWP ratio and the clinical picture.
Cites:Hsu 2022
rapcwp-highDescriptive patternhighDraft — pending review
Not a reference range. A description of findings occurring together, not a diagnosis.
RAP is high relative to the wedge (RAP:PCWP above 0.63)
when RAP ≥ 10 mmHg and RAP:PCWP > 0.63
A right-sided pressure that is disproportionate to the left suggests RV-predominant or biventricular failure; it is also the pattern of pericardial constraint and tricuspid disease. There is no universal cutoff: 0.63 comes from the pre-LVAD cohort (Kormos), and shock studies use varying definitions of hemodynamic RV dysfunction. The ratio is only meaningful when the RAP is itself elevated.
Evidence
Threshold borrowed from a pre-LVAD cohort; not a validated general cutoff.
Cites:Kormos 2010 Hsu 2022
rv-failure-patternDescriptive patternalertDraft — pending review
Not a reference range. A description of findings occurring together, not a diagnosis.
Hemodynamic RV-failure pattern: high RAP, RAP high relative to wedge, low cardiac index
when RAP ≥ 15 mmHg and RAP:PCWP > 0.63 and cardiac index < 2.2 L/min/m²
A descriptive, teaching-defined combination (RAP ≥15, RAP:PCWP above 0.63, CI below 2.2). In the SHOCK trial and registry analysis, hemodynamically defined RV dysfunction was common (about 37–38% of patients with cardiogenic shock after MI), but its association with survival was not statistically significant by that study's criteria, so this pattern should not be read as predicting outcome.
Evidence
Teaching-defined combination, not a validated category.
Cites:Lala 2018 Kormos 2010

Systemic afterload · 3

svr-lowReference rangelowDraft — pending review
Low systemic vascular resistance
when SVR < 800 dyn·s·cm⁻⁵
Band set: SVR · band 1 of 3 · edges <800 | <1400
Vasodilation: sepsis, cirrhosis, anaphylaxis, vasodilator drugs, or the inflammatory vasoplegia of late cardiogenic shock.
Cites:Naderi 2024 Kern 2022
svr-normalReference rangenormalDraft — pending review
Systemic vascular resistance within the reference range
when 800 ≤ SVR < 1400 dyn·s·cm⁻⁵
Band set: SVR · band 2 of 3 · edges <800 | <1400
Naderi's table gives 800–1200 (text: 900–1440); Kern gives 700–1600. A healthy adult with MAP 90, RAP 4 and CO 5.2 L/min has an SVR of about 1320, so the narrow 800–1200 band would mislabel healthy people; the app uses 800–1400.
Evidence
Sources disagree on the upper limit (1200 vs 1440 vs 1600).
Cites:Naderi 2024 Kern 2022
svr-highReference rangehighDraft — pending review
Elevated systemic vascular resistance
when SVR ≥ 1400 dyn·s·cm⁻⁵
Band set: SVR · band 3 of 3 · edges <800 | <1400
Vasoconstriction: the compensatory response to low output (cardiogenic or hypovolemic) or vasopressor effect. Afterload reduction may raise output if filling pressures allow.
Cites:Naderi 2024 Kern 2022

Cardiac power · 2

cpo-lowPrognostic cutoffalertDraft — pending review
Not a reference range. An outcome cutoff from a derivation cohort. Being on the favorable side does not make a value normal.
Cardiac power output below 0.6 W
when cardiac power < 0.6 W
Band set: Cardiac power · band 1 of 2 · edges <0.6
CPO = MAP × CO / 451. In the SHOCK trial registry, CPO was the strongest hemodynamic correlate of in-hospital mortality in cardiogenic shock (0.53 W was the derivation cutoff; 0.6 W is the commonly used threshold). Resting normal is about 1 W.
Population
Derived in cardiogenic shock (SHOCK registry)
Cites:Fincke 2004 SCAI 2022
cpo-okPrognostic cutoffinfoDraft — pending review
Not a reference range. An outcome cutoff from a derivation cohort. Being on the favorable side does not make a value normal.
Cardiac power output at or above the 0.6 W shock-prognosis threshold
when cardiac power ≥ 0.6 W
Band set: Cardiac power · band 2 of 2 · edges <0.6
This is a prognostic cutoff from patients in cardiogenic shock, not a reference range: a value above it does not establish normal pump function. Resting normal is about 1 W, and CPO should be read with MAP, cardiac output and clinical perfusion.
Population
Derived in cardiogenic shock (SHOCK registry)
Cites:Fincke 2004

References

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Note: Replaces the 2016 listing criteria. Statements about its content in this app come from secondary summaries and are marked as pending verification against the full text.
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Known disagreements

Two different 'cutoffs' on the same axis: PCWP 15 vs 18, CI 2.5 vs 2.2
- ESC/ERS 2022Mean PCWP ≤15 mmHg classifies a pulmonary hypertension as pre-capillary (a diagnostic definition).
- Forrester 1976PCWP above 18 mmHg marks pulmonary congestion and CI below 2.2 L/min/m² marks hypoperfusion (a teaching framework).
- Naderi 2024Cardiac index 2.5–4.0 L/min/m² is the reference range.
What Swanology does: These are not competing estimates of the same thing. The rule table tags each with its kind (diagnostic, framework, reference), and the 'Swanology uses' rows say which kind the app's band is. PCWP rules
Definition of pulmonary hypertension: mPAP threshold
- ESC/ERS 2022mPAP >20 mmHg (resting), following the 6th World Symposium.
- Naderi 2024mPAP ≥25 mmHg, the pre-2018 definition still used in the library chapters.
What Swanology does: The engine uses >20 and labels 21–24 as 'meets the current definition, borderline under older ones'. ph-mild-range
PVR threshold for the pre-capillary component
- ESC/ERS 2022>2 WU.
- WSPH 2018≥3 WU (and Naderi and Kern use 3).
What Swanology does: The engine uses >2 WU and flags 2–3 WU as a gray zone classified differently by the two definitions. pvr-gray-zone
Normal systemic vascular resistance
- Naderi 2024800–1200 dyn·s·cm⁻⁵ in the table; the text says 900–1440.
- Kern 2022700–1600 dyn·s·cm⁻⁵.
What Swanology does: The app uses 800–1400: a healthy adult with MAP 90, RAP 4 and CO 5.2 has an SVR of about 1320, which the narrow 800–1200 band would mislabel. SVR range
v-wave height as a marker of mitral regurgitation severity
- Foucha 2009A v wave more than twice the mean wedge pressure indicates significant MR.
- Bootsma 2022v-wave height does not predict MR severity (Kern agrees): compliance of the left atrium and loading conditions dominate.
What Swanology does: Swanology teaches the v wave as a clue to look for MR, not as a severity grade, and does not use it in any rule.
Signature of over-wedging
- Kern 2022An over-wedged tracing is damped and reads falsely low.
- Bootsma 2022An over-wedged tracing rises progressively and reads falsely high.
What Swanology does: Both patterns occur (occlusion against the vessel wall vs. flushing against an occluded tip); the pitfalls module shows both and the engine withholds PVR when PCWP exceeds mPAP.
RA a wave vs v wave dominance
- Kern 2022States that the a wave is normally greater than the v wave in the right atrium, but Table 22.2 lists a mean v wave (5) close to the a wave (6) with overlapping ranges: an internal inconsistency.
- Damrongwatanasuk 2026a ≥ v in the right atrium; v > a in the left atrium / wedge.
What Swanology does: The waveform model draws a ≥ v in the RA and v > a in the wedge, following the manuscript.
Naderi's PVR table vs text
- Naderi 2024The table gives normal PVR as <250 dyn·s·cm⁻⁵ (3.1 WU); the text says <2 WU (160 dyn).
- ESC/ERS 2022>2 WU is abnormal.
What Swanology does: The app follows the guideline (2 WU) and shows both of Naderi's values in the reference-range table. PVR range
PAPi cutoffs are cohort-specific
- Korabathina 2012PAPi ≤0.9 identified severe RV dysfunction in acute inferior MI.
- Morine 2016PAPi <1.85 predicted RV failure after LVAD implant (other cohorts suggest ~2).
What Swanology does: The engine applies 0.9 only when the acute inferior MI flag is set and 1.85 only for LVAD evaluation (both population-specific). Outside those settings it describes PAPi <2 as a pattern (a small RV pulse pressure relative to RA pressure) and makes no outcome claim. papi-general-low
Thermodilution accuracy in severe tricuspid regurgitation
- Melin 2026Against directly measured-VO₂ Fick (852 paired studies, shunt excluded), agreement did not differ by TR grade. Thermodilution tended to read high at low flow and low at high flow.
What Swanology does: Severe TR does not switch the cardiac output method. Both values are shown with a scrutiny message, and the app does not state that thermodilution is unreliable in severe TR. This study did not test assumed-VO₂ Fick, so it says nothing about how good that estimate is.
Which wedge value: mean PAWP or end-diastolic PAWP
- Baratto 2023Defines mean PAWP (whole cardiac cycle, includes v waves) and end-diastolic PAWP (mid-a wave in sinus rhythm), and finds PAWP accurate but imprecise for LVEDP during supine exercise. It does not say which value to use for PVR.
- ESC/ERS 2022PVR and PH classification are defined from mean pressures.
What Swanology does: PVR, TPG and PH classification use the cardiac-cycle MEAN wedge, which is an app convention because PVR is defined from mean pressures; Baratto 2023 does not support or contradict it. The end-diastolic wedge is held separately as an LVEDP surrogate.
Is a high RAP:PCWP ratio or low PAPi prognostic outside the original cohort?
- Kormos 2010RAP:PCWP above 0.63 was associated with RV failure after LVAD implant (pre-LVAD cohort).
- Lala 2018Hemodynamic RV dysfunction was common (about 37–38%), but its association with survival was not statistically significant; specific cutoffs including 0.8 are not verified here.
What Swanology does: No prognostic claim is made. 0.63 is used only as the pre-LVAD cutoff from Kormos 2010, and elsewhere as a teaching-defined threshold for a descriptive pattern. rapcwp-high

What was verified and what was not

A literature claim in a teaching app is only as good as the reading behind it. For each source whose content is easy to over-state, this lists what was checked in the text, what was not, and what the app does as a result. Items marked as secondary or review-level are not to be read as verified against a primary text.

Melin 2026: thermodilution vs direct Fick
Checked, with limits
Cited:Melin 2026
What was verified
- Thermodilution compared with direct Fick (measured VO₂) in 852 paired studies; intracardiac shunt excluded.
- Agreement did not differ by TR severity.
- Thermodilution tended to read high at low flow and low at high flow.
What was not
- Assumed-VO₂ Fick was not studied, so the paper says nothing about its accuracy.
- Patients with intracardiac shunt were excluded, so it does not apply to them.
What Swanology does: The app does not claim that thermodilution is unreliable in severe TR. Both Fick (labelled direct or estimated) and thermodilution are shown, with a scrutiny message when TR is severe.
Baratto 2023: mean vs end-diastolic wedge pressure
Checked, with limits
Cited:Baratto 2023
What was verified
- Simultaneous right and left heart catheterization during supine exercise in 46 patients.
- Defines mean PAWP (whole cardiac cycle, includes v waves) and end-diastolic PAWP (mid-a wave in sinus rhythm).
- PAWP was accurate but imprecise as an estimate of LVEDP.
What was not
- The paper does not address which PAWP to use for PVR.
- It studied supine exercise in patients with dyspnea, not resting values in other populations.
What Swanology does: Using the MEAN wedge for PVR and PH classification is an app convention, chosen because PVR is defined from mean pressures. It is not a finding of Baratto 2023. The end-diastolic wedge is the LVEDP surrogate.
Lala 2018: hemodynamic RV dysfunction in cardiogenic shock
Checked, with limits
Cited:Lala 2018
What was verified
- Hemodynamically defined RV dysfunction was common (about 37–38%).
- Its association with survival was not statistically significant.
What was not
- The specific cutoffs used, including a RAP:PCWP of 0.8, are unverified.
What Swanology does: The app makes no prognostic claim about RV dysfunction. 0.63 is used only as the pre-LVAD cutoff from Kormos 2010 and, elsewhere, as a teaching-defined threshold for a descriptive pattern. 0.8 is not used.
2022 ESC/ERS guideline: acute vasoreactivity testing
Text checked
Cited:ESC/ERS 2022
What was verified
- Inhaled nitric oxide (10–20 ppm) and inhaled iloprost are the recommended agents; intravenous epoprostenol is an alternative.
- Intravenous adenosine is no longer recommended.
- The guideline’s definition of a positive response was read from the text.
- Testing is restricted to idiopathic, heritable and drug-associated PAH (IPAH/HPAH/DPAH).
What was not
- Agent doses beyond those stated and local stopping rules are protocol-specific and not reproduced here.
What Swanology does: Statements about PAH vasoreactivity testing are checked against this text. The transplant-evaluation challenge is a separate question with a different source (next item).
ISHLT 2024 candidate guideline: vasodilator challenge in transplant evaluation
Secondary sources only
Cited:ISHLT 2024
What was verified
- Nothing was read from the guideline itself. Secondary summaries report that PASP ≥50 mmHg with TPG ≥15 mmHg or PVR ≥3 WU, while maintaining systolic pressure above 85 mmHg, prompts a stepwise approach.
- The summarized steps are: an acute vasodilator challenge, then inpatient therapy, then consideration of mechanical circulatory support.
What was not
- The full guideline text has not been checked. Every number and step above is flagged for verification against it.
What Swanology does: The rule is labelled population-specific and as a trigger for further testing, not a determination of eligibility. It cites the guideline but states that the content is from secondary summaries.
Exercise hemodynamic criteria
Checked, with limits
Cited:ESC/ERS 2022 ERS 2017
What was verified
- The guideline text was checked for the supine exercise slope thresholds.
What was not
- No upright-exercise thresholds have been verified.
- Thresholds for other exercise protocols have not been checked.
What Swanology does: Only supine slope thresholds are presented as guideline-based. No upright threshold should be read as verified.
SvO₂ interpretation
Review-level sources
Cited:Naderi 2024 Hsu 2022
What was verified
- Interpretation is based on review-level sources: a normal or high SvO₂ can coexist with tissue hypoxia, classically in sepsis, when extraction is impaired.
What was not
- No primary study was checked for the SvO₂ statements. The PAH risk-table thresholds (65% and 60%) are prognostic cutoffs from the guideline, not a reference range.
What Swanology does: An SvO₂ within the reference range is never described as proof of adequate oxygen delivery.

Sources & rules

How the interpretation engine works

Reference range vs diagnostic criterion vs prognostic cutoff vs population-specific finding vs teaching framework vs descriptive pattern

Reference ranges and look-alike thresholds

Right atrial pressure (mean) (mmHg)

RA a wave (mmHg)

RA v wave (mmHg)

RV systolic (mmHg)

RV end-diastolic (mmHg)

PA systolic (mmHg)

PA diastolic (mmHg)

PA mean (mmHg)

PCWP (mean) (mmHg)

LA mean (mmHg)

Aortic / arterial mean (mmHg)

Cardiac index (L/min/m²)

Stroke volume (mL/beat)

Mixed venous O₂ saturation (%)

Systemic vascular resistance (dyn·s·cm⁻⁵)

Pulmonary vascular resistance (WU)

Transpulmonary gradient (mmHg)

Diastolic pulmonary gradient (mmHg)

PA pulsatility index

RAP : PCWP ratio

Cardiac power output (W)

Band edges

RAP edges: <2 | ≤6 | ≤10 | ≤15

Mean PCWP edges: <5 | ≤12 | ≤15 | ≤18 | <25

Cardiac index edges: <2 | <2.2 | <2.5 | ≤4

SvO₂ edges: <50 | <60 | ≤80

SVR edges: <800 | <1400

Mean PA pressure edges: ≤20

Cardiac power edges: <0.6

Qp:Qs edges: <1 | <1.5 | ≤2

Rule table

Right-sided filling · 6

Low right atrial pressure

Right atrial pressure within the reference range

Mildly elevated right atrial pressure

Moderately elevated right atrial pressure

Markedly elevated right atrial pressure

Equalized diastolic pressures (RAP ≈ PADP ≈ PCWP)

Left-sided filling · 6

Low wedge pressure

Mean wedge pressure within the reference range

Mean wedge pressure above the reference range but not above 15

Mean wedge pressure above 15 mmHg (post-capillary range)

Mean wedge pressure above 18 mmHg

Severely elevated mean wedge pressure

Cardiac output · 5

Cardiac index below the reference range but above the low-output cutoff

Cardiac index within the reference range

High cardiac index

Severely reduced cardiac index

Reduced cardiac index (below the 2.2 low-output cutoff)

Oxygen delivery · 6

Very low mixed venous saturation

Low mixed venous saturation

Mixed venous saturation within the reference range

High mixed venous saturation

SvO₂ in the intermediate-risk band of the PAH risk table

SvO₂ below the high-risk threshold of the PAH risk table

Pulmonary circulation · 13

Mean PA pressure not above 20 mmHg

Pulmonary hypertension by the resting mPAP definition

mPAP between 20 and 25 mmHg: meets the current definition, 'borderline' under older ones

Pre-capillary pulmonary hypertension

Isolated post-capillary pulmonary hypertension

Combined pre- and post-capillary pulmonary hypertension

Pulmonary hypertension with normal PVR and wedge

PVR between 2 and 3 WU: pre-capillary by 2022 criteria, not by 2018 criteria

DPG of 7 or more supports a pre-capillary component

Meets the combination that prompts a vasodilator challenge in transplant evaluation

Elevated PVR without pulmonary hypertension

PVR is inflated by low cardiac output

Severely elevated PVR (above 5 WU)

Right ventricle · 9

PAPi below 0.9 in acute inferior MI

PAPi at or above 0.9 in acute inferior MI

PAPi below 1.85 before LVAD