The pathophysiology of Ebstein's anomaly depends on the morphology of tricuspid valve and the right ventricle.  The annulus of the valve is in normal position. The valve leaflets however, are to a varying degree attached to the walls and septum of the right ventricle. There is subsequent atrialization of a portion of the morphologic right ventricle (which is then contiguous with the right atrium). This causes the right atrium to be large and the anatomic right ventricle to be small in size. 50% of cases involve an atrial shunt (either a PFO or an ASD). 
Mutations in MYH7, which a sarcomere gene encoding the cardiac beta-myosin heavy chain have been linked in the occurence of familial Ebstein anomaly. Commonly associated conditions include  Aortic coarctation, Cleft anterior leaflet of the mitral valve, Coarctation of the aorta, corrected transposition of the great arteries, Hypoplastic pulmonary arteries, Left ventricular outflow obstruction etc.
Ebsteins anomaly of the tricuspid valve pathophysiology
Ebsteins anomaly of the tricuspid valve risk factors
Ebsteins anomaly of the tricuspid valve causes
Arrhythmogenic right ventricular dysplasia pathophysiology
Ebsteins anomaly of the tricuspid valve differential diagnosis
Aneurysm of sinus of valsalva pathophysiology
Ebsteins anomaly of the tricuspid valve other diagnostic studies
Bicuspid aortic stenosis pathophysiology