Pulmonary vein flow

PV S/D, Ar−A · PW Doppler 1–2 cm into the right upper pulmonary vein (A4C with colour guidance)

Normal range & thresholds

• S/D ≤0.67 supports elevated LA pressure (ASE 2025 step 2) — but S/D <1 is normal in young adults ^[2].
• Ar − A duration ≥30 ms indicates elevated LV end-diastolic pressure ^[2].
• Ar velocity >35 cm/s supports raised LVEDP.

Pathophysiology

Systolic forward flow (S) depends on LA relaxation and mitral annular descent; diastolic flow (D) mirrors mitral E. As LA pressure rises, S shrinks and D dominates. The atrial reversal (Ar) lengthens when atrial contraction pushes blood backward into a stiff LV ^[2].

Raised by

• S dominance: normal adults >40 y, hyperdynamic states

Lowered by

• S blunting: elevated LAP, severe MR (systolic reversal), AF (no Ar, blunted S)

Technique & pitfalls

• Sample volume 2–3 mm, 1–2 cm into the vein; low wall filter; sweep 50–100 mm/s.

Pseudo-change & artefact

• Young age (physiological D dominance), AF, MR, poor alignment.

Treatment thresholds

• Adjudicates LAP in step 2 of the ASE 2025 algorithm ^[2]; systolic flow reversal is a specific sign of severe MR ^[4].

Next step

• Combine with LASr and LAVI.

Drugs

Diuresis restores S dominance acutely.

Reversibility

Reverses with filling pressure.