Auscultation of heart murmurs is an essential clinical skill for diagnosing heart conditions. By listening to specific heart sounds, healthcare professionals can identify abnormalities such as murmurs, irregular rhythms, or valve dysfunction.
This guide breaks down everything you need to know, from understanding the basics of auscultation to recognizing common heart murmurs and when to seek medical attention.
What Is Auscultation of Heart Sounds?
Auscultation of heart sounds involves listening to the sounds produced by your heart as it pumps blood. Doctors use a stethoscope to identify normal and abnormal sounds. These sounds, such as S1, S2, S3, and S4, help assess the function of your heart valves and blood flow.
- S1: The “lub” sound marks the closure of the mitral and tricuspid valves.
- S2: The “dub” sound occurs when the aortic and pulmonic valves close.
- S3: A low-pitched sound is heard after S2, often due to rapid blood flow into the ventricles.
- S4: A rare sound heard before S1, associated with stiff or thickened heart walls.
The 5 Areas of the Heart for Auscultation
Listening to specific areas of the chest helps pinpoint where abnormalities originate. These 5 areas of the heart for auscultation are:
Aortic Area:
- Location: Right second intercostal space, near the sternum.
- Purpose: Best for detecting murmurs caused by the aortic valve, like aortic stenosis murmur.
Pulmonic Area:
- Location: Left second intercostal space.
- Purpose: Evaluate issues in the pulmonary valve, such as pulmonary regurgitation.
Erb’s Point:
- Location: Left third intercostal space.
- Purpose: Ideal for hearing both S1 and S2 sounds, providing a balanced view of overall heart function.
Tricuspid Area:
- Location: Lower left side of the sternum at the fourth intercostal space.
- Purpose: Detects tricuspid valve issues, often associated with pan systolic murmurs.
Mitral Area:
- Location: Left fifth intercostal space, near the mid-clavicular line.
- Purpose: Key for assessing mitral valve problems, such as mitral regurgitation or stenosis.
Diagram of Heart Sounds Auscultation Areas
Visualizing the auscultation areas simplifies understanding. Here’s how the regions align with their corresponding valves and sounds:
| Auscultation Area | Location | Best Heard Sounds |
| Aortic | Right second intercostal | Systolic murmurs, especially aortic stenosis |
| Pulmonic | Left second intercostal | Pulmonary valve sounds |
| Erb’s Point | Left third intercostal | The equal intensity of S1 and S2 sounds |
| Tricuspid | Left the fourth intercostal | Tricuspid murmurs and pan systolic murmurs |
| Mitral | Left the fifth intercostal | Mitral valve murmurs, including regurgitation |
Recognizing Heart Sounds: S1, S2, S3, and S4
Each heart sound provides crucial information about your heart’s function:
- S1: Loudest at the mitral and tricuspid areas, marking the beginning of systole (heart contraction).
- S2: Best heard at the aortic and pulmonic areas, signaling the end of systole and the start of diastole (heart relaxation).
- S3: Indicates rapid ventricular filling, often associated with heart failure.
- S4: Suggests decreased ventricular compliance, linked to conditions like hypertension.
Knowing these sounds helps differentiate normal heart activity from murmurs or other abnormalities.
Types of Heart Murmurs You Should Know
Heart murmurs result from turbulent blood flow within the heart. Some are harmless (innocent murmurs), while others indicate serious conditions.
Heart murmurs occur when blood flows abnormally through the heart or its valves. These murmurs are often classified based on their timing, sound, and underlying cause. Here’s a breakdown of the main types of heart murmurs you should know.
1. Systolic Murmurs
Systolic murmurs occur during the heart’s contraction (systole). They are further divided into two types based on their duration and pattern.
A. Ejection Murmurs
- Cause: Turbulent blood flow through narrowed or stiff valves.
- Example: Aortic stenosis murmur, caused by the narrowing of the aortic valve.
- Sound: Crescendo-decrescendo (gradual increase and decrease in intensity).
- Location: Best heard in the aortic area.
B. Pansystolic (Holosystolic) Murmurs
- Cause: Blood flowing backward (regurgitation) through a valve.
- Example: Mitral regurgitation or tricuspid regurgitation.
- Sound: Uniform, continuous murmur throughout systole.
- Location: Best heard in the tricuspid or mitral areas.
2. Diastolic Murmurs
Diastolic murmurs occur when the heart relaxes (diastole). These murmurs are usually caused by issues with valve opening or regurgitation during this phase.
A. Early Diastolic Murmurs
- Cause: Regurgitation of blood through valves that fail to close completely.
- Example: Aortic regurgitation or pulmonary regurgitation.
- Sound: High-pitched, decrescendo murmur.
- Location: Best heard at the left sternal border.
B. Mid-Diastolic Murmurs
- Cause: Blood flowing through narrowed valves during diastole.
- Example: Mitral stenosis or tricuspid stenosis.
- Sound: Low-pitched rumbling murmur.
- Location: Best heard with the bell of the stethoscope at the mitral or tricuspid areas.
3. Continuous Murmurs
Continuous murmurs occur throughout both systole and diastole. They result from abnormal connections between blood vessels or heart chambers.
- Cause: Persistent blood flow due to structural defects.
- Example: Patent ductus arteriosus (PDA) or arteriovenous fistula.
- Sound: “Machinery-like” murmur.
- Location: Often heard at the left upper chest.
4. Functional (Innocent) Murmurs
Functional murmurs, also known as innocent murmurs, occur in healthy hearts due to increased blood flow. They are common in children and during pregnancy.
- Cause: Temporary conditions like fever, anemia, or exercise.
- Sound: Soft, short, and low-pitched.
- Location: Typically heard across the chest without a specific focal point.
Comparison of Common Murmur Types
| Type | Cause | Sound | Key Features |
| Aortic Stenosis Murmur | Narrowed aortic valve | Crescendo-decrescendo during systole | Heard best at the aortic area |
| Pansystolic Murmur | Regurgitation through mitral or tricuspid valve | Continuous during systole | Best heard at the mitral/tricuspid areas |
| Diastolic Murmur | Narrowed mitral/tricuspid valve or regurgitation | Low-pitched rumble or high-pitched decrescendo | Heard during heart relaxation |
| Continuous Murmur | Structural abnormalities like PDA | Machinery-like throughout the cardiac cycle | Often heard at the left upper chest |
| Innocent Murmur | Normal increased blood flow | Soft and low-pitched | No symptoms or treatment needed |
When Should You Be Concerned About a Heart Murmur?
While many murmurs are harmless, others may signal serious heart problems. Seek medical advice if you experience:
- Chest pain.
- Persistent fatigue or weakness.
- Shortness of breath.
- Swelling in the lower body.
- Dizziness or fainting.
A doctor will conduct tests like echocardiograms or electrocardiograms (ECG) to determine if the murmur requires treatment.
By understanding these types of heart murmurs, you can gain insights into what might be happening with your heart and when to consult a healthcare professional.
Conclusion: The Importance of Auscultation of Heart Murmurs
Auscultation of heart murmurs is a crucial skill for detecting heart problems early. By understanding the heart sounds, the 5 auscultation areas, and the types of murmurs, you can better manage your heart health. If you ever notice unusual symptoms, don’t delay reaching out to a healthcare professional.
