-most serious abnormality of Atrial Septal Defects

- complete absence of atrial septum

1. normal septum formation but excessive resorption of septum primum

2. Absence of septum secundum

-obliteration (destruction) of the rt. atrioventricular orifice (passage)

-Characteristics

* patent oval foramen

* ventricular Septal defects

* underdeveloped right ventricle

* Left ventricle hypertrophy

1. Defect of the membranous part of intermuscular septum = mixed blood in pul. trunk

2. defect of muscular part of Intermuscular septum aka Swiss Cheese VSD

3. Absence of Interventricular septum

The heart and the vessels are reversed due to heart tube bending to the left durign development instead of right

*** compatible w/ life

-rare

- Heart is in abnormal position

- Heart is either totally or partially exposed

- Widely separated sternum

- Open pericardial sac

- Death in few days after birth

1. Turbulence

2. Eddies -- small whirlpools

3. murmers

1. degenerative process in teh cardiovascular fibrous skeleton

2. enhanced stress and abnormal valve motion accelerate degenerative process, leading to premature calcium deposition

- commonly involved involves the arotic and mitral valve

- thickining usually involves chrodae tendineae, valve cusps & leaflets

-Failure of spiral conotruncal septum to follow its course causes:

1. Aorta to originate from right ventricle

2. Pulmonary Trunk orginates from left ventricle