Auscultation in Primary Care First and Second Heart Sounds - Normal and Unsplit - waveform Lesson Waveform Video play pause Maneuver:Supine Position:Mitral Chestpiece:Diaphragm Table of Contents Introduction First and Second Heart Sounds - Normal and Unsplit First and Second Heart Sounds - Reduced Intensity Second Heart Sound - Splitting Third Heart Sound Gallop Fourth Heart Sound Gallop Third and Fourth Heart Sound Gallop Summation Gallop at 120 beats per minute Second Heart Sound - Fixed Splitting Mid-Systolic Click Mitral Valve Leaflet Prolapse Aortic Stenosis (Diamond Shaped Systolic Murmur) Aortic Regurgitation (Decrescendo Diastolic Murmur) Mitral Regurgitation (pansystolic Murmur) Mitral Stenosis (Diastolic Murmur) 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.