You are examining a 70-year-old male patient who is being ev…

You are examining a 70-year-old male patient who is being evaluated for an episode of syncope.  Auscultation of his heart reveals a mid-systolic ejection murmur, medium pitch, crescendo-decrescendo, heard best at the second right intercostal border with the diaphragm of the stethoscope.  The sound of this murmur radiates to his neck.   Which heart murmur is present?