- 1. Cardiac Chambers
a) Right atrium
· Wide based blunt appendage, crista terminalis separates trabeculated from non-trabeculated portion
b) Left atrium
· Long, narrow appendage, smooth walls
c) Right ventricle
· Coarsely trabeculated inlet/sinus, outlet portion
d) Left ventricle
· Fine trabeculations inlet/sinus and outlet portions
· SVC - IVC
· Crista terminalis
· Coronary sinus
· Tricuspid valve
· Fossa ovalis
· Triangle of Koch
· Tendon of Todaro
- 3. Right Ventricle
a) Inlet portion supports tricuspid valve
b) Trabecular sinus portion (main body of the RV)
· Moderator band
· Medial papillary muscle (of conus)
c) Outlet portion
· Infundibular (Conal) septum (separates semilunar valves)
· Crista supra ventricularis - seperates sinus (chamber) from outlet portion of the ventricle
· Septal band (trabecula septomarginalis)
· Parietal band (ventriculo-infundibular fold)
· Pulmonary valve
- 4. Left Ventricle
· Thick wall
· Inlet portion supports mitral valve
· Anterior and posterior papillary muscles
· Outlet portion beneath aortic valve
- 5. Conduction System
· Sinoatrial node - anterolateral RA
· Interatrial conduction pathways - not well defined and somewhat controversial
· Atrioventricular node - triangle of Koch
· Bundle of His - AV node to membranous septum, usually located on the inferior/posterior wall of the membranous septum
· Left bundle branch - left ventricular septal surface
· Right bundle branch - below medial papillary muscle
- 6. Cardiac Valves
a) Aortic valve wedged between mitral and tricuspid, pulmonary valve separated
b) Mitral valve
· Anterior leaflet wide, short, 1/3 of annular circumference
· Posterior leaflet narrow, long, 2/3 of annular circumference
· Papillary muscles and chordae tendineae
c) Tricuspid valve
· Anterior, posterior, septal leaflets
d) Aortic and pulmonary valves
· 3 cusp, semilunar
· Sinuses of Valsalva
- 7. Left Ventricular Outflow Tract
· Semilunar aortic valve
· Fibrous annulus is not a ring
· Interleaflet triangles
· Aortoventricular junction
· Sinuses of Valsalva
· Sinotubular junction (sinus rim) = junction of sinus of Valsalva and ascending aorta
· Posterior commissure relates to mid point of anterior leaflet of mitral valve
- 8. Coronary Arteries
· Right and left coronary arteries
· Dominant pattern determined by origin of posterior descending
· Dominance is usually right or balanced; 10-15% prevalence of left dominance
· Balanced pattern occurs when there is no particular dominance
· Septal blood supply 2/3 left anterior descending, 1/3 posterior descending
· Sinus node artery from RCA - 55%
· AV node artery from U bend at crux, just beyond the takeoff of the PDA if circulation is right dominant
- 9. Descriptive Variables
a) Situs of thoracic viscera and atria
· This is best identified from the bronchial anatomy (3 bronchi on the right, 2 on the left)
· Solitus, inversus, ambiguous
b) Situs of ventricles
· Usual, concordant, D-loop, right-handedness
· Inverted, discordant, L-loop, left-handedness
c) Dominance of ventricles
· Balanced (usual), right (left small), left (right small)
- 10. Descriptive Variables
a) Cardiac connections
· Atrioventricular and ventriculoarterial
· Concordant or discordant (transposed)
b) Cardiac and arterial position
· Cardiac apex; levo-, dextro-, mesocardia
· Great arteries; transposition, malposition
· The patient can have completely normal cardiac structures and still have dextrocardia - this only refers to the position of the cardiac apex
c) Conventional diagnosis; e.g., tetralogy of Fallot