Heart and Lung Sounds Reference Guide Aortic Pulmonic Erb's Point Tricuspid Mitral Lungs Fourth Heart Sound Auscultation Reference Signup Now. Unlock lessons and more. SignUp Patient Normal Speed play pause Patient Half Speed play pause Simulated Full Speed play pause Lesson For heart sounds listen to the synthetic sound while reviewing this lesson. Certain heart sound configurations mimic a split first heart sound.One of these conditions is a fourth sound gallop (S4) plus a first heart sound (S1). Since the S4 occurs just before the S1 it is easy to confuse a S4/S1 with a split S1.An S4 is lower frequency than an S1. To differentiate between a S4/S1 and a split S1, listen carefully to the frequency of the initial sound of the pair. If it is lower in frequency than the second sound it is an S4. If the two sounds are the same it is a split S1. The waveform(s) seen above are a chart of sound amplitude (loudness) on the vertical axis against time on the horizontal axis. Listening Tips A summary of the key aspects of this heart or lung sound. Diastole: S4 present - a low pitched sound. Auscultation Method The recommended patient position is supine For this sound, use stethoscope's bell The recommended auscultation position for the stethoscope is mitral Relevant Courses If you wish to review a complete mobile concerning Fourth Heart Sound Auscultation Reference and related heart sounds, the modules(s) listed below may be useful. Each lesson includes text that explains the auscultatory sound and its clinical significance. The lesson also includes an audio track for playback. A waveform provides a great way to visualize the sounds. Finally, we also include an animation video. For heart sounds, the video illustrates heart muscle and valve movements along with blood flow. For lung sounds, the primary source of the sounds can be seen. Each module also includes a quiz. First Heart Sounds23 Fourth Heart Sound Auscultation Reference