Difference between revisions of "Ebsteins anomaly of the tricuspid valve pathophysiology"
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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).
- Pathophysiology mainly involves the right ventricle, right atrium and tricuspid valve.
- They include:
- Failure of TV leaflet delamination
- Apical descent of the functional tricuspid orifice
- Right ventricular dilation and “atrialization”
- Anterior leaflet abnormal fenestrations and tethering
- Right atrioventricular junction dilation
- The superficial layer of the right myocardium usually delaminates to form the septal and posterior leaflets of the tricuspid valve.
- Any Delamination failure might result in adherence of the leaflets to the ventricular myocardium as a result causes apical displacement of the tricuspid valve leaflets.
- The tricuspid valve orifice is in normal position.
- The anterior leaflet of the tricuspid valve is attached to the tricuspid valve annulus or to the right ventricular endocardium.
- The septal and posterior leaflets of the tricuspid valve are absent most of the time.
- Due to these changes, the tricuspid valve may become funnel-shaped and incompetent or leaky.
The right ventricle changes secondary to the malformed tricuspid valves. The right ventricle can be divided into two parts by the malformed valve:
- The downward extension of the tricuspid valve causes 'atrialization' of the proximal part of the right ventricle
- The small distal part, the right ventricle proper, thus is reduced in size and sometimes comprises only of the right ventricular outflow tract
- Till now the genetic basis for this condition is largely unknown or very little is known about this.
- Mutations in MYH7, which a sarcomere gene encoding the cardiac beta-myosin heavy chain have been linked in the occurance of familial Ebstein anomaly.
- It is formulated that embryonic cell migration may be impaired by these MYH7 mutations.
Commonly associated conditions include:
A complete list of associated conditions includes the following:
- Aortic coarctation
- Cleft anterior leaflet of the mitral valve
- Coarctation of the aorta
- Congenital deaf-mutism
- Corrected transposition of the great arteries
- Hypertensive pulmonary vascular disease
- Hypoplastic pulmonary arteries
- Left ventricular outflow obstruction
- Mitral valve prolapse
- Parachute mitral valve
- Partial atrioventricular canal
- Patent ductus arteriosus
- Pulmonary atresia with an intact ventricular septum
- Pulmonary stenosis
- Subaortic stenosis
- Tetralogy of Fallot
- Ventricular septal defect (VSD)
- Kloesel B, DiNardo JA, Body SC (September 2016). "Cardiac Embryology and Molecular Mechanisms of Congenital Heart Disease: A Primer for Anesthesiologists". Anesth. Analg. 123 (3): 551–69. doi:10.1213/ANE.0000000000001451. PMC 4996372. PMID 27541719.
- Postma AV, van Engelen K, van de Meerakker J, Rahman T, Probst S, Baars MJ, Bauer U, Pickardt T, Sperling SR, Berger F, Moorman AF, Mulder BJ, Thierfelder L, Keavney B, Goodship J, Klaassen S (February 2011). "Mutations in the sarcomere gene MYH7 in Ebstein anomaly". Circ Cardiovasc Genet. 4 (1): 43–50. doi:10.1161/CIRCGENETICS.110.957985. PMID 21127202.
- Bettinelli AL, Mulder TJ, Funke BH, Lafferty KA, Longo SA, Niyazov DM (December 2013). "Familial ebstein anomaly, left ventricular hypertrabeculation, and ventricular septal defect associated with a MYH7 mutation". Am. J. Med. Genet. A. 161A (12): 3187–90. doi:10.1002/ajmg.a.36182. PMID 23956225.
- Holst KA, Connolly HM, Dearani JA (2019). "Ebstein's Anomaly". Methodist Debakey Cardiovasc J. 15 (2): 138–144. doi:10.14797/mdcj-15-2-138. PMC 6668741 Check
|pmc=value (help). PMID 31384377.