The third heart sound is heard early in diastole. Along with the first and second heart sounds, this extra sound creates a gallop cadence and sounds like "Kentucky."
In this auscultation example the second heart sound is unsplit to make it easier for you to distinguish the third heart sound.
The third heart sound is very low frequency (between 25Hz and 50Hz). Listen with the bell of the stethoscope at the cardiac apex. Asking the patient to lie on his left side will frequently increase the intensity of the third heart sound.
A third heart sound is heard on occasion in normal individuals with no cardiac pathology.
Third Heart Sound - Physiologic Audio
Third Heart Sound - Physiologic Sounds
Half Speed Third Heart Sound - Physiologic Sounds
Technique
The patient's position should be supine.
Auscultation Tips for Third Heart Sound - Physiologic
S2:UnsplitDiastole:S3 in early diastole. Low-pitch. Galloping (S1,S2,S3) or intermittent sound
Sound Wave
Third Heart Sound - Physiologic 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
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ECG Reference Guide
PracticalClinicalSkills.com
Third Heart Sound - Physiologic | #35
