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.
Fourth Heart Sound Plus First Heart Sound Audio
 
                        
Fourth Heart Sound Plus First Heart Sound Sounds
 
                        
Half Speed Fourth Heart Sound Plus First Heart Sound Sounds
 
                        
Technique
 
                The patient's position should be supine.
Auscultation Tips for Fourth Heart Sound Plus First Heart Sound
Diastole:S4 present - a low-pitched soundSound Wave
Fourth Heart Sound Plus First Heart Sound Video
Authors and Sources
Authors and Reviewers
- ECG heart rhythm modules: Thomas O'Brien.
- ECG monitor simulation developer: Steve Collmann
- 
                    12 Lead Course: Dr. Michael Mazzini, MD.
- Spanish language ECG: Breena R. Taira, MD, MPH
- Medical review: Dr. Jonathan Keroes, MD
- Medical review: Dr. Pedro Azevedo, MD, Cardiology
- Last Update: 11/8/2021 
Sources
- 
                    
                        Electrocardiography for Healthcare Professionals, 6th Edition
                    
                    Kathryn Booth and Thomas O'Brien
 ISBN10: 1265013470, ISBN13: 9781265013479
 McGraw Hill, 2023
- 
                    
                        Rapid Interpretation of EKG's, Sixth Edition
                    
                    
 Dale Dublin
 Cover Publishing Company
- 
                        EKG Reference Guide
 EKG.Academy
- 
                    
                        12 Lead EKG for Nurses: Simple Steps to Interpret Rhythms, Arrhythmias, Blocks, Hypertrophy, Infarcts, & Cardiac Drugs
                    
                    
 Aaron Reed
 Create Space Independent Publishing
- 
                    
                        Heart Sounds and Murmurs: A Practical Guide with Audio CD-ROM 3rd Edition
                    
                    
 Elsevier-Health Sciences Division
 Barbara A. Erickson, PhD, RN, CCRN
- 
                    
                        The Virtual Cardiac Patient: A Multimedia Guide to Heart Sounds, Murmurs, EKG
                    
                    Jonathan Keroes, David Lieberman
 Publisher: Lippincott Williams & Wilkin)
 ISBN-10: 0781784425; ISBN-13: 978-0781784429
- Project Semilla, UCLA Emergency Medicine, EKG Training Breena R. Taira, MD, MPH
- 
                        ECG Reference Guide
 PracticalClinicalSkills.com
Fourth Heart Sound Plus First Heart Sound | #42




