Echo KB
Sign in →
← Section III · Chamber Size and Function
III.G

Right Atrium

5 cards

Notes

RA size

  • Measured in the RV-focused A4C view at end-systole.
  • Upper limit of normal: RA area ≤ 18 cm².
  • Enlarged in: chronic TR, RV failure, chronic AF, tricuspid stenosis, restrictive cardiomyopathy, ASD (with left-to-right shunt).

RA thrombi

  • Most common cause: catheter- or pacemaker-lead-related.
  • May migrate from lower extremity DVT (thrombus-in-transit) - echo may catch it in transit through RA to RV.

Anatomic landmarks in the RA

  • Eustachian valve - inferior vena cava valve.
  • Thebesian valve - coronary sinus valve.
  • Chiari network - remnant of embryonic right valve of sinus venosus; fenestrated web-like structure.
  • Crista terminalis - ridge separating the smooth-walled sinus venosus portion from the trabeculated RA; often mistaken for a mass on TEE.

Normal RA Doppler patterns (hepatic vein PW)

  • Normal HV: dominant systolic (S) wave forward, small diastolic (D) wave, small atrial reversal (Ar).
  • Severe TR: systolic HV flow reversal.
  • Constrictive pericarditis: dominant systolic wave forward with prominent diastolic reversal on expiration.

Cards

  • basicIII.G-001
    State the RA area cutoff for right atrial enlargement.
    → > 18 cm² measured in the RV-focused apical 4-chamber view at end-systole.
  • basicIII.G-002
    Name three normal anatomic RA structures that are commonly mistaken for pathology.
    → 1) Eustachian valve (IVC valve). 2) Chiari network (fenestrated web from embryonic right valve of sinus venosus). 3) Crista terminalis (ridge separating smooth from trabeculated RA — often confused for a mass on TEE).
  • basicIII.G-003
    What is the Chiari network?
    → A fenestrated web-like remnant of the embryonic right valve of the sinus venosus in the RA — a normal variant, not pathologic.
  • basicIII.G-004
    Most common source of RA thrombus in a patient without indwelling hardware?
    → Migratory thrombus from a lower extremity deep vein thrombosis ('thrombus-in-transit') — often precedes pulmonary embolism.
  • basicIII.G-005
    How does severe TR appear on hepatic vein PW Doppler?
    → Systolic flow reversal in the hepatic vein. (Normal HV has a dominant systolic forward wave.)