SS de FM = sopro sistólico em foco mitral
http://www.esquina.cardiol.br/manualc/T_MIOCARDIOPATIAS.pdf

The mitral area (foco mitral) is located at the left fifth intercostal space, in the midclavicular line. It is the usual location where the apex beat (ictus cordis) can be felt. In English, "mitral area" is less common than "left 5th intercostal space, etc. etc.", but it is used.
http://books.google.com/books?id=OlYVAAAAIAAJ&pg=RA1-PA34&dq...
http://www.patient.co.uk/doctor/Heart-Auscultation.htm

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Note added at 27 mins (2009-12-30 11:59:00 GMT)
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By the way, if you're like me and like to do a bit of extra research (always useful for future jobs), here is an image containing the usual points for precordial auscultation. The "foco mitral" corresponds to B7.
http://anatomytopics.files.wordpress.com/2009/01/auscultatio...