MEDiscuss • Cardiovascular diseases • Valve disease effects on heart chambers

Hello,

I'm looking over aortic and mitral stenosis/regurgitation and trying to work out the pathophysiology behind these conditions.

The question is what effect does aortic stenosis have on the left atrium? I know that hypertrophy of the left ventricle occurs and thought that there may be slight hypertrophy of the atrium due to increasing pressures but I'm unsure. Also how is its function affected?

Similarly, what effect does mitral stenosis have on the left ventricle? I thought it may dilate to attempt to accommodate increased filling but, again, I'm unsure.

Any help would be great, thank you.

what effect does aortic stenosis have on the left atrium? I know that hypertrophy of the left ventricle occurs and thought that there may be slight hypertrophy of the atrium due to increasing pressures but I'm unsure. Also how is its function affected?

You are right, aortic stenosis results in a pressure overload of the left ventricle (LV) that leads to hypertrophy of that chamber. With time, as pressure builds in the left ventricle, there is a backward pressure build-up and even the left atrium (LA) dilates.

Function of left atrium in aortic stenosis: A dilated LA is a compensatory mechanism for maintaining atrial emptying [1]. As the hypertrophied LV has reduced compliance or increased stiffness, this dilatation of LA is important to maintain the LV stroke volume and cardiac output.

Similarly, what effect does mitral stenosis have on the left ventricle? I thought it may dilate to attempt to accommodate increased filling but, again, I'm unsure.

Opposite, actually. In mitral stenosis, LA pressure rises to maintain LV filling. But, despite this elevated pressure gradient across the mitral valve, LV filling (end-diastolic volume is) is reduced. This reduced filling, by Frank Starling's mechanism (Starling's law) *, will reduce the LV stroke volume, cardiac output and the aortic pressure.

Function of left ventricle in mitral stenosis: Reduced LV stroke volume in mitral stenosis is due to reduced LV filling (because of a smaller mitral orifice), and consequent invocation of Starling's law.

Hope this explanation is clear.

hi↲
thank u capatrick i was have a similar que. And it was v.benfit for me dr.Shasikeran ↲
so the dilatation of the chambers is a mechanism to overcome the large voliume of the blood traped in it while the hypertrophy is a mechanism that strengthing the heart ↲mmuscles to over come the high pressure gradient,,i have been always confused why this chamber dilated or hypertrophid am i got the correct understanding?now??↲also i want to ask how the lef or the right atria increase theire pressure in case of M.S or T.S ??