Right atrial volume index

RAVI · RA-focused apical 4-chamber, end-systole, single-plane method of discs

Normal range & thresholds

Pathophysiology

Raised by

• Right ventricular failure of any cause — the commonest reason
• Pulmonary hypertension (all groups); chronic thromboembolic disease
• Tricuspid regurgitation, primary or secondary; tricuspid stenosis; Ebstein anomaly; carcinoid
• Atrial fibrillation/flutter — biatrial dilatation is the rule
• Atrial septal defect and anomalous pulmonary venous return (volume load)
• Constrictive pericarditis and restrictive cardiomyopathy — biatrial enlargement with normal ventricles
• Volume overload: renal failure, over-transfusion; pacemaker and defibrillator leads causing lead-induced TR
• Endurance athletes (proportionate, with normal function)

Lowered by

• Hypovolaemia and over-diuresis
• Tamponade (RA collapse)
• Small body size
• Extrinsic compression by a mass or effusion

Technique & pitfalls

• Use an RA-focused apical 4-chamber view — the standard 4-chamber view is optimised for the left heart and cuts the RA obliquely.
• Measure at end-systole, just before tricuspid valve opening (maximum RA volume).
• Exclude the appendage, the inferior and superior vena cava, and the area below the tricuspid annular plane; exclude the Eustachian valve and Chiari network.
• Method of discs is preferred over area–length in the 2025 guideline; index to BSA.^[3]
• Report RA area as well when pulmonary hypertension is the question — the risk tables use area, not volume.

Pseudo-change & artefact

• Foreshortening in the standard 4-chamber view — under-measures.
• Including the vena cavae or the appendage — over-measures.
• Volume status and the timing of dialysis.
• Positive-pressure ventilation raises right atrial pressure and size.
• Prominent Eustachian valve or Chiari network traced as a border.
• Atrial fibrillation: average multiple cycles.

Treatment thresholds

• Pulmonary hypertension risk stratification is where this parameter carries formal weight: RA area <18 cm² = low risk, 18–26 cm² = intermediate, >26 cm² = high risk in the ESC/ERS multiparametric table, and risk status drives the aggressiveness of initial combination therapy and the timing of transplant referral.^[8]
• Tricuspid intervention: progressive RA and RV dilatation with a still-preserved RV supports intervening before the ventricle fails; severe RV dysfunction and precapillary pulmonary hypertension are exclusions from transcatheter tricuspid therapy in the 2025 ESC/EACTS guidelines.^[6,65]
• Atrial septal defect: right heart volume overload — dilated RA and RV with a significant shunt (Qp:Qs ≥1.5) — is itself the indication for closure, regardless of symptoms.^[25]
• No isolated RAVI number triggers therapy on its own.

Next step

• Next: quantify tricuspid regurgitation, estimate systolic pulmonary artery pressure, and assess RV size and function (TAPSE, S′, FAC, free-wall strain).
• Then: IVC size and collapse for right atrial pressure; hepatic vein Doppler for the systolic-flow reversal of severe TR.
• Then: agitated-saline contrast for shunt; TOE or CMR when a shunt or Ebstein anomaly is suspected.
• Then: if pulmonary hypertension is probable, V/Q scanning and right heart catheterisation — the haemodynamic diagnosis cannot be made by echo alone.^[8]

Drugs

• Diuretics and salt restriction reduce RA size acutely, and are the mainstay of right heart decongestion.^[8]
• Pulmonary vasodilators (endothelin receptor antagonists, PDE-5 inhibitors, prostacyclin analogues, riociguat) reduce RA area over months in group 1 pulmonary hypertension — RA area is a follow-up target in the risk tables.^[8]
• Rate and rhythm control in atrial arrhythmia.
• Avoid excessive fluid loading; be cautious with agents that worsen right-sided volume status.

Reversibility