Normal Heart Sounds First and Second Heart Sounds - Normal and Unsplit This is a normal first and second heart sound at 60 beats per minute. You are auscultating at the Mitral valve area (Apex). The first heart sound has slightly greater intensity than the second heart sound.The first heart sound is produced by the closing of the mitral and tricuspid valve leaflets.The second heart sound is produced by the closing of the aortic and pulmonic valve leaflets.The second heart sound is unsplit when the subject is holding his or her breath at peak expiration. play pause Position: Mitral Chestpiece: Diaphragm Maneuver: Supine Phonocardiogram Cardiac Animation Table of Contents 1First and Second Heart Sounds - Normal and Unsplit 2First Heart Sound (Minimally Split) 3Second Heart Sound - Physiologically Split #1 4Third Heart Sound - Physiologic 5Innocent Murmur 6Exercise - Heart Rate 120 Practice Drill