Table of ContentsView AllTable of ContentsAbout S3CausesHeart Failure TreatmentOther Heart SoundsMonitoring and ManagementWhen to See a Provider
Table of ContentsView All
View All
Table of Contents
About S3
Causes
Heart Failure Treatment
Other Heart Sounds
Monitoring and Management
When to See a Provider
A third heart sound, or S3, is a low-frequency, extra heart sound that may be heard with a stethoscope right after the normal S1 and S2 heart sounds. S1 and S2 are the “lub-dub” sounds of a heartbeat and represent heart valves closing as blood cycles through the heart’s chambers.
An S3 represents blood striking the walls of a stretched ventricle (heart chamber). It is usually associated with heart failure (the heart cannot pump enough blood for the body’s needs), although in children or young adults, it may be a normal finding that disappears with age.
Hispanolistic / Getty Images
How to Hear the S3 SoundCompared toS1andS2,S3has a lower pitch and is much fainter. It’s best heard when a healthcare provider places the bell of their stethoscope (the small circular part) on a person’s chest wall while they are lying on their left side.
How to Hear the S3 Sound
Compared toS1andS2,S3has a lower pitch and is much fainter. It’s best heard when a healthcare provider places the bell of their stethoscope (the small circular part) on a person’s chest wall while they are lying on their left side.
What Is the S3 Heart Sound?
To best understand theS3 heart sound, you must first understand how normal heart sounds—S1 and S2—are generated.
The heart muscle consists of the following:
The valves open and close as blood continuously moves through the heart, preventing blood from flowing in the wrong direction.Normal heart sounds—S1 and S2—are generated when one or more of these valves close.
The first heart sound,S1, occurs when the mitral and tricuspid valves close. These valves close as the ventricles pump blood out of the heart into the lungs or body—this is calledsystole.
The second heart sound,S2, occurs when the aortic and pulmonary valves close. These valves close as the ventricles relax and fill with blood—this isdiastole.
S1occurs at the beginning of systole and is the “lub” of a heartbeat.S2occurs at the beginning of diastole and is the “dub” of a heartbeat.
IfS3is present, it occurs right after S2 in diastole.S3reflects rapid ventricle stretching (distension) as blood quickly fills it, hitting the ventricle walls.
S3may be present in healthy children or young adults. However, in adults over 40, it’s almost always abnormal, representing an early sign ofcongestive heart failure(heart failure with a buildup of fluid in the veins and tissues of the lungs and other parts of the body).
AnS3is sometimes called a “ventricular gallop.” The term “gallop” was first coined in the mid-1800s to describe the classic triple-sound rhythm heard when anS3is present, along with the usualS1andS2sounds.
Causes of S3 Sound
A third heart sound suggests that one of the ventricles (usually the left ventricle) is stretched or enlarged, a typical early finding in heart failure.
Heart failure can be classified as:
An S3 is more frequently heard with systolic heart failure compared to diastolic heart failure.
Common causes of a third heart sound include:
An S3 can also be present in pregnancy and in athletes with slower heart rates. In such cases, the third heart sound is usually harmless and not a sign of heart failure.
Risk Factors for Heart FailureConditions or factors that increase a person’s chances of developing heart failure include:DiabetesAbnormal heart rhythms (arrhythmias)ObesityHigh cholesterolHistory of smokingHigh blood pressure
Risk Factors for Heart Failure
Conditions or factors that increase a person’s chances of developing heart failure include:DiabetesAbnormal heart rhythms (arrhythmias)ObesityHigh cholesterolHistory of smokingHigh blood pressure
Conditions or factors that increase a person’s chances of developing heart failure include:
Treatment for Heart Failure
Heart failure therapiesaim to ease symptoms and help prevent the condition from worsening.Though treatments vary based on the type, cause, and severity of heart failure, they typically involve a combination of lifestyle behaviors and medication.
Additionally, because heart failure can affect the heart’s electrical activity, one or more devices placed underneath the skin in the upper chest area may be necessary.
Lifestyle
Generally advised lifestyle behaviors for individuals with heart failure include:
Speak With a Healthcare ProviderIf you have heart failure, talk with a healthcare provider before starting an exercise regimen. They may refer you tocardiac rehabilitation, an exercise program customized to optimize your heart health safely.
Speak With a Healthcare Provider
If you have heart failure, talk with a healthcare provider before starting an exercise regimen. They may refer you tocardiac rehabilitation, an exercise program customized to optimize your heart health safely.
Medications
Heart failure medications help reduce symptoms and vary in type and dosing.
A typical heart failure medication regimen includes:
Other heart failure medications include:
Devices
Some people with heart failure are candidates for placement of a device, either animplantable cardioverter defibrillator (ICD),cardiac resynchronization therapy (CRT) pacemaker, or both.
S3 Compared to Other Heart Sounds
A fourth heart sound—S4—is another abnormal heart sound.
LikeS3,S4is low-pitched and best heard with the bell of astethoscope. If present, anS4also occurs in diastole but in later diastole (right beforeS1), whereasS3is heard in early diastole (right beforeS2).
The presence of a fourth heart sound reflects a stiff and inflexible left ventricle. It may be heard with the following conditions:
BesidesS3andS4, there are alsoheart murmurs, which are extra or unusual vibratory heart sounds.
Heart murmursmay be harmless (“innocent”), sometimes heard in young children or during pregnancy. They can also indicate a type of heart disease, like a faulty valve or acongenital (present at birth) heart defect.
Ongoing Heart Monitoring and Management
For most people with heart failure, it’s a lifelong condition that requires close follow-up with various providers, including:
In addition to attending appointments, individuals living with heart failure will need to monitor their fluid and salt intake and keep track of their weight at home. Based on their medications, they will also undergo periodic blood tests (e.g., potassium level).
Regulating Potassium Levels in Heart Failure
When to See a Healthcare Provider
Seek medical attention if you are experiencing possible symptoms or signs of heart failure.
These may include:
Summary
A third heart sound, or S3, is a low-pitched extra heart sound classically associated with heart failure, although it may be normal in children and young adults. It can also be normal in athletes or during pregnancy. The third heart sound reflects blood striking the wall of a stretched or enlarged ventricle (one of the heart’s lower chambers).
Other causes of heart failure and a third heart sound include coronary artery disease (clogged arteries that feed the heart muscle), heart valve disease, and chronically high blood pressure.
Treatment of heart failure involves a combination of lifestyle behaviors (e.g., limiting salt intake and avoiding smoking) and a medication regimen that usually consists of three or more drugs.
Because heart failure can impact the heart’s electrical system, your healthcare team may also advise placing one or more devices—an ICD or biventricular pacemaker—underneath the skin in the chest area.
Seek medical care if you are told you have an S3 and/or are experiencing possible symptoms of heart failure like breathlessness, fatigue, a persistent cough, or swelling in your ankles or stomach.
16 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
National Heart, Lung, and Blood Institute.How blood flows through the heart.
Cascino T, Shea M.J.Cardiac auscultation. Merck Manual Professional Version.
Meyer TE.Auscultation of heart sounds. In: UpToDate, Gersch BJ, (Ed), Wolters Kluwer
Silverman ME.The Third Heart Sound. InClinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Walker HK, Hall WD, Hurst JW, editors. Boston: Butterworths; 1990. Chapter 24
American Heart Association.Dilated cardiomyopathy.
National Heart, Lung, and Blood Institute.What is coronary heart disease?
Armstrong GP.Overview of cardiac valvular disorders. InMerck Manual Professional Version. Merck & Co., Inc. 2023.
Heidenreich PA, Bozkurt B, Aguilar D, et al.2022 AHA/ACC/HFSA guideline for the management of heart failure: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines.Circulation. 2022;101161CIR0000000000001063. doi:10.1161/CIR.0000000000001063
Pencina MJ, Navar AM, Wojdyla D, et al.Quantifying importance of major risk factors for coronary heart disease.Circulation. 2019;139(13):1603-1611. doi:10.1161/CIRCULATIONAHA.117.031855
National Heart, Lung, and Blood Institute.Heart failure: treatment.
Meyer TE.Primary pharmacologic therapy for heart failure with reduced ejection fraction. In: UpToDate, Gottlieb SS. (Ed), Wolters Kluwer.
Talha KM, Anker SD, Butler J.SGLT-2 inhibitors in heart failure: a review of current evidence.Int J Heart Fail.2023;5(2):82-90. doi: 10.36628/ijhf.2022.0030
Spartalis M, Nakajima K, Zweiker D, et al.Contemporary ICD use in patients with heart failure.Cardiol Ther.2021;10(2):313-324. doi:10.1007/s40119-021-00225-7
Yokoshiki H, Mitsuyama H, Watanabe M, et al.Cardiac resynchronization therapy in ischemic and non-ischemic cardiomyopathy.J Arrhythm. 2017;33(5):410-416. doi:10.1016/j.joa.2017.03.002
American Heart Association.Heart failure signs and symptoms.
Meet Our Medical Expert Board
Share Feedback
Was this page helpful?Thanks for your feedback!What is your feedback?OtherHelpfulReport an ErrorSubmit
Was this page helpful?
Thanks for your feedback!
What is your feedback?OtherHelpfulReport an ErrorSubmit
What is your feedback?
