This report describes a therapeutic alternative for correction of severe mitral stenosis causing high-response atrial fibrillation, and consequent syncope in a woman at 8 weeks gestational age. A percutaneous valvuloplasty attempt failed, because the transseptal puncture was not possible, and a definitive resolution was achieved by transapical valvuloplasty, via left thoracotomy through an inframammary incision, with direct access to the mitral valve. Since this was an original and complex procedure, this case is of relevant importance in the treatment of severe mitral stenosis in patients whose conditions render a conventional procedure impossible.