Trans thoracic c ardiac windows • and standard 2d sections

Normal Variants and Benign Conditions Often Misinterpreted as Pathologic
■ Right atrium

1. 
   Chiari network
   
2. 
   Eustachian valve
   
3. 
   Crista terminalis
   
4. 
   Catheters/pacemaker leads
   
5. 
   Lipomatous hypertrophy of interatrial septum
   
6. 
   Pectinate muscles
   
7. 
   Fatty material (surrounding the tricuspid annulus)
   

■ Left atrium

1. 
   Suture line following transplant
   
2. 
   Fossa ovalis
   
3. 
   Calcified mitral anulus
   
4. 
   Coronary sinus
   
5. 
   The ridge between LUPV and LAA
   
6. 
   Lipomatous hypertrophy of interatrial septum
   
7. 
   Pectinate muscles
   
8. 
   Transverse sinus
   

■ Right ventricle

1. 
   Moderator band
   
2. 
   Muscle bundles/trabeculations
   
3. 
   Catheters and pacemaker leads
   

■ Left ventricle

1. 
   False chords
   
2. 
   Papillary muscles
   
3. 
   LV trabeculations
   

NORMAL ANATOMIC VARIANTS IN THE RIGHT ATRIUM

• 
  Anatomic variants are particularly common in the right atrium.
  
• 
  The right sinus valve of embryonic sinus venosus normally regresses forming the crista terminalis and
  
• 
  the Eustachian valve.
  
• 
  Such regression process is highly variable.
  
• 
  Incomplete regression results in a spectrum of vestiges, such as the Chiari network, Eustachian valve of inferior vena cava, Thebesian valve of the coronary sinus, and a prominent crista terminalis.