Changes

[[Image:dilated left atrium.jpg|right|thumb|125px|<small><center>'''Dilated left atrium'''. Courtesy of T. Scase</center></small>]]

[[Image:dilated left atrium.jpg|right|thumb|125px|<small><center>'''Dilated left atrium'''. Courtesy of T. Scase</center></small>]]

In most cases the mitral valve is affected, the tricuspd valve is less commonly involved and the semilunar valves even less commonly involved.

In most cases the mitral valve is affected, the tricuspd valve is less commonly involved and the semilunar valves even less commonly involved.

Incompetent valves allow mitral regurgitation and left atrial dilation.  The regurgitant jet applies damaging forces on the atrial endocardium which may result in [[Endocardial - Pathology#Endocardial_Mineralisation|endocardial mineralisation]] and in extreme cases may facilitate left atrial rupture and haemopericardium.

Incompetent valves allow mitral regurgitation and left atrial dilation.  The regurgitant jet applies damaging forces on the atrial endocardium which may result in [[Endocardial_Mineralisation|endocardial mineralisation]] and in extreme cases may facilitate left atrial rupture and haemopericardium.

''Cinical Signs:''<br>

''Cinical Signs:''<br>