Right Heart Cath and Hemodynamics Basics
Read right-heart-cath numbers conceptually — filling pressures, output, and what they tell you.
Learning Objectives
- 1.Understand what a right heart catheterization measures.
- 2.Interpret the key hemodynamic numbers conceptually.
- 3.Know when RHC is used and the APP’s scope.
Overview
Right heart catheterization measures the pressures and flow of the circulation. You won’t perform it, but understanding the numbers helps you interpret shock, heart failure, and pulmonary hypertension.
What RHC measures
- •Right atrial (RA) pressure — right-sided filling/volume.
- •Pulmonary artery (PA) pressure — pulmonary circulation.
- •Pulmonary capillary wedge pressure (PCWP/"wedge") — estimates left atrial/left-sided filling pressure.
- •Cardiac output/index (CO/CI) — how much blood the heart is pumping.
- •Calculated resistances (PVR, SVR).
Interpreting conceptually
- •High wedge → left-sided congestion (e.g., LV failure / Group 2 PH).
- •High PA pressure with a normal wedge → pre-capillary pulmonary hypertension (e.g., PAH).
- •Low cardiac output with high filling pressures → cardiogenic shock physiology.
- •Low filling pressures with low output → hypovolemic/distributive picture (different problem).
When RHC is used
- •Confirming and characterizing pulmonary hypertension.
- •Sorting shock and guiding therapy in the ICU.
- •Advanced heart failure evaluation (e.g., transplant/LVAD assessment).
Scope
This is conceptual understanding for follow-up, complication recognition, and escalation. APPs do not perform these procedures, program devices beyond recognition/triage, or read raw images — those are the proceduralist’s/imager’s role.
Common beginner mistakes
- •Confusing a high wedge (left-sided) with pre-capillary PH.
- •Ignoring cardiac output when interpreting filling pressures.
- •Over-interpreting numbers without the clinical context.
Mini cases
RHC: high PA pressure, high wedge, low cardiac output in a dyspneic HF patient.
Interpretation?
Show answer
High wedge indicates left-sided congestion (the PH is "post-capillary"/Group 2 from left heart disease), and low output reflects the failing pump — consistent with decompensated HF, not primary PAH. Manage the heart failure and coordinate with the physician.
RHC: high PA pressure but a NORMAL wedge.
What does that suggest?
Show answer
Elevated PA pressure with a normal wedge suggests pre-capillary pulmonary hypertension (e.g., PAH/Group 1 or CTEPH) — refer to a PH specialist; this is not simple left-heart congestion.