Auscultation in Primary Care Summation Gallop at 120 beats per minute At a heart rate of 120 beats per minute, the diastolic period is shortened. This causes the third and fourth sound to be superimposed, creating a single loud sound.The anatomy tab shows an enlarged left ventricle with decreased left ventricular contractility and a minimally enlarged left atrium. play pause Position: Mitral Chestpiece: Diaphragm Maneuver: Supine Phonocardiogram Heart Animation Table of Contents 1First and Second Heart Sounds - Normal and Unsplit 2First and Second Heart Sounds - Reduced Intensity 3Second Heart Sound - Splitting 4Third Heart Sound Gallop 5Fourth Heart Sound Gallop 6Third and Fourth Heart Sound Gallop 7Summation Gallop at 120 beats per minute 8Second Heart Sound - Fixed Splitting 9Mid-Systolic Click 10Mitral Valve Leaflet Prolapse 11Aortic Stenosis (Diamond Shaped Systolic Murmur) 12Aortic Regurgitation (Decrescendo Diastolic Murmur) 13Mitral Regurgitation (pansystolic Murmur) 14Mitral Stenosis (Diastolic Murmur) Practice Drill