Right Heart Cath

Last updated: April 9, 2026, Pacific Time (PDT)

Interactive RHC interpreter for pulmonary-hypertension physiology. Enter PA, wedge, and cardiac output values to calculate PVR / gradients and classify pre-capillary, isolated post-capillary, combined post/pre-capillary, or no resting PH.

RHC Measurements

RAP / CVP

PA systolic

PA diastolic

mPAP

PAWP / PCWP

Cardiac output

Cardiac index

BSA if no CO

Formulas: PVR = (mPAP - PAWP) / CO. TPG = mPAP - PAWP. DPG = PA diastolic - PAWP. If mPAP is missing, the tool estimates mPAP = (PA systolic + 2 x PA diastolic) / 3 and labels it as estimated.

Hemodynamic classification

Awaiting RHC values

Enter mPAP, PAWP, and cardiac output when available.

Calculated values

No derived hemodynamics yet.

Interpretation flags

No flags yet.

TTE Context

optional; supportive context only

RVSP / PASP estimate

Peak TR velocity

TAPSE

LVEF

Echo findings

RV dilation RV dysfunction Septal flattening / D-sign RA enlargement LA enlargement Diastolic dysfunction / high filling pressures Moderate-severe left-sided valve disease Known / suspected intracardiac shunt

TTE can suggest PH probability and RV strain, but the hemodynamic PH type above is classified from RHC values.

Clinical Context

optional; helps suggest WHO group

Select plausible drivers

LV systolic / diastolic disease Mitral / aortic valve disease CTD, portal HTN, HIV, drug/toxin, heritable PAH risk COPD / ILD / emphysema OSA / chronic hypoxia / hypoventilation Prior PE, V/Q defects, chronic thromboembolic concern

Suggested PH type / workup focus

Hemodynamic classification and context will appear here.

Hemodynamic Definitions

Resting RHC buckets

No resting PH: mPAP 20 mmHg or less.
Pre-capillary PH: mPAP > 20, PAWP 15 or less, PVR > 2 WU.
Isolated post-capillary PH: mPAP > 20, PAWP > 15, PVR 2 WU or less.
Combined post- and pre-capillary PH: mPAP > 20, PAWP > 15, PVR > 2 WU.
Unclassified PH physiology: mPAP > 20 with PAWP 15 or less and PVR 2 WU or less; think high-flow states or measurement context.

Waveform / data-quality checks

Confirm wedge waveform, end-expiratory PAWP, and PAWP oxygen saturation if the wedge is surprising.
Interpret PVR only when cardiac output method / value is reliable.
If PAWP is normal but left-heart disease is strongly suspected, consider expert review, volume challenge, or exercise hemodynamics.

Clinical PH Group Clues

Group 1 / PAH pattern

Usually pre-capillary PH on RHC.
Look for CTD, portal HTN, HIV, congenital heart disease, drugs/toxins, heritable PAH.
Exclude group 2, group 3, and CTEPH before anchoring.

Group 2 / left-heart disease

Post-capillary PH: PAWP > 15.
Can be isolated post-capillary or combined post/pre-capillary when PVR is high.
Correlate with EF, diastology, LA size, valve disease, MR, AS, volume status.

Group 3 / lung or hypoxia

Usually pre-capillary PH.
Correlate with PFTs, DLCO, CT chest, exertional oxygenation, sleep-disordered breathing.
Very high PVR should prompt careful search for overlapping PAH or CTEPH.

Group 4 / CTEPH

Pre-capillary PH physiology.
Screen with V/Q scan when chronic thromboembolic disease is plausible.
Refer early to PH / CTEPH center if suspected.

Group 5 / multifactorial

Consider when PH is disproportionate or fits systemic / hematologic / metabolic disease.
Examples include sarcoid, renal failure contexts, myeloproliferative disease, complex high-output states.

Sources