Auscultation in Primary Care Third and Fourth Heart Sound Gallop C31 - Both the third and fourth heart sounds (S3 and S4) are low frequency. S4 is lower than S3. This is a pattern that occurs with improvement of heart failure. That is, an S3 pattern gives way to an S3 S4 pattern as the patient improves. Listen The patient's position should be supine. VisualizeObserve LessonsFirst and Second Heart Sounds - Normal and Unsplit C31.First and Second Heart Sounds - Reduced Intensity C31.Second Heart Sound - Splitting C31.Third Heart Sound Gallop C31.Fourth Heart Sound Gallop C31.✓Third and Fourth Heart Sound Gallop C31.Summation Gallop at 120 beats per minute C31.Second Heart Sound - Fixed Splitting C31.Mid-Systolic Click C31.Mitral Valve Leaflet Prolapse C31.Aortic Stenosis (Diamond Shaped Systolic Murmur) C31.Aortic Regurgitation (Decrescendo Diastolic Murmur) C31.Mitral Regurgitation (pansystolic Murmur) C31.Mitral Stenosis (Diastolic Murmur) C31.Sign-in to enable progress reports and certificates.