Asymptomatic middle aged woman with some severe heart problem. Soon she had cardiac surgery. Can you make a diagnosis from this audio fragment of her heart sound (apex of the heart, left decubitus position; use headphones!):

Ok, a little prompting: there is one low-frequency pathological sign. Listen again (use headphones!):

In my opinion, it is an incredibly difficult case, but the pathological sound is evident. 

Look at the phonocardiogram:

There is a late-systolic low-frequency murmur which waxes and wanes completely randomly. S1 is loud. Try to hear this murmur:

So, this patient has mitral stenosis. But not so simple.

This patient had a large left atrial myxoma, which prolapsed into the mitral valve orifice and made mitral stenosis.

The diagnosis was made before I listened to this patient and I knew the diagnosis when I inspected her. I have been listening to her heart at least ten minutes, probably even more, hoping to hear some sign of myxoma. But I did not hear anything when I inspected this patient. I made some recordings of her heart sound and listened to it two or three times when finally I noticed late-diastolic low-frequency murmur. It happened a few years later. 

My problem was simple: every time while listening to this sound I was trying to hear early diastolic tumour sound because I thought that it is the most frequent symptom, but it is not. It seems to me that auscultatory picture of left atrial myxoma is variable. Here you can find another case. 

There is only one key to help differentiate myxoma and valvular mitral stenosis: the pre-systolic murmur of valvular mitral stenosis is nearly unchanging, while all additional sounds of left atrial myxoma change every time waxing and waning.

Here you can download heart sound of two cases of left atrial myxoma. Listen to it carefully, and probably you will be able to find a myxoma before echocardiography one day.