Opening Snap and Second Heart SoundAn opening snap occurring early in diastole along with a single second heart sound can mimic a split second heart sound. An opening snap is caused by thickened valve leaflets. When they open, it produces a snapping sound. The more severe the thickening the earlier in diastole the opening snap occurs. In this example you are hearing an opening snap, which occurs 75 milliseconds after the start of the second heart sound.
Patient Recording - Half Speed
The patient's position should be supine.
Listening TipsDiastole:Snap early in diastole, higher-pitch than S2
Observe Cardiac Animation
An opening snap is caused by thickened valve leaflets. When they open it, produces a snapping sound. The more severe the thickening the earlier in diastole the opening snap occurs. In this example you are hearing an opening snap which occurs 75 milliseconds after the start of the second heart sound.
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Authors and Sources
Authors and Reviewers
- EKG heart rhythm modules: Thomas O'Brien.
- EKG monitor simulation developer: Steve Collmann
12 Lead Course: Dr. Michael Mazzini, MD.
- Spanish language EKG: Breena R. Taira, MD, MPH
- Medical review: Dr. Jonathan Keroes, MD
Heart sounds and mentorship: W. Proctor Harvey, MD
- Medical review: Dr. Pedro Azevedo, MD, Cardiology
Last Update: 1/8/2023
Electrocardiography for Healthcare Professionals, 5th Edition
Kathryn Booth and Thomas O'Brien
ISBN10: 1260064778, ISBN13: 9781260064773
McGraw Hill, 2019
Rapid Interpretation of EKG's, Sixth Edition
Cover Publishing Company
12 Lead EKG for Nurses: Simple Steps to Interpret Rhythms, Arrhythmias, Blocks, Hypertrophy, Infarcts, & Cardiac Drugs
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
- Clinical Heart Disease
W Proctor Harvey, MD
Clinical Heart Disease
Laennec Publishing; 1st edition (January 1, 2009)
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
Opening Snap and Second Heart Sound | #52