Pediatric Heart Sounds & Murmurs
Heart Sounds
Welcome to our educational webpage dedicated to understanding pediatric heart sounds and murmurs. This platform is designed for medical students and professionals aiming to master auscultation skills and enhance their diagnostic capabilities in pediatrics. Our webpage provides a detailed guide to both normal and pathological heart sounds, specifically focusing on the unique characteristics of pediatric patients.
We offer in-depth explanations of normal heart sounds, including S1, S2, and physiological variations like S3 and S4, commonly found in children. Each sound is accompanied by mp3 audio recordings that highlight their distinct features, such as pitch, intensity, and timing. Additionally, our section on murmurs includes classifications such as systolic, diastolic, and continuous murmurs, with audio clips and visual aids to help correlate the sounds with their underlying conditions, including congenital heart defects and valvular abnormalities.
Designed for educational purposes, our webpage ensures accessibility and engagement through downloadable audio files, interactive quizzes, and real-life case studies. Whether you are a medical student preparing for exams or a professional refining your diagnostic skills, this resource provides a structured approach to understanding heart sounds and murmurs in pediatric patients. By combining high-quality audio and clear explanations, we aim to empower learners in the field of pediatric cardiovascular assessment.
For an optimal learning experience, we recommend using headphones while listening to the heart sounds. This ensures clarity and helps you distinguish subtle variations in heart sounds and murmurs, which are crucial for accurate clinical interpretation.
Normal Heart Sounds
Normal heart sounds in children include the first heart sound (S1) and the second heart sound (S2), which are generated by the closure of heart valves during the cardiac cycle. S1 is associated with the closure of the mitral and tricuspid valves, while S2 corresponds to the closure of the aortic and pulmonary valves. These sounds may vary slightly in intensity and duration compared to adults due to the faster heart rate and more elastic chest wall in children. Listen to the provided audio clips of S1 and S2, and compare them to understand their characteristics and rhythm.
Normal Heart Sounds
First Heart Sound (S1)
Definition: Represents the closure of atrioventricular valves (mitral and tricuspid valves)
Pediatric Characteristics:
- Louder and sharper than in adults
- Higher frequency due to smaller valve size
- More easily heard at all auscultation points
- Split S1 more commonly heard due to thinner chest wall
Adult Differences: Lower pitch and intensity, less likely to hear physiologic splitting
Second Heart Sound (S2)
Definition: Represents closure of semilunar valves (aortic and pulmonic valves)
Pediatric Characteristics:
- Physiologic splitting more prominent and dynamic
- Wider split during inspiration (especially in ages 2-8 years)
- A2 and P2 components more easily distinguished
- P2 often softer than A2 in children
Adult Differences: Less pronounced physiologic splitting, components harder to distinguish
Third Heart Sound (S3)
Key Feature: Normal finding in children aged 2-16 years
- Best heard at apex in left lateral position
- Low-pitched "Kentucky gallop" rhythm
- Represents rapid ventricular filling
- More common in thin-chested children
Adult Difference: Usually pathological after adolescence, associated with ventricular dysfunction
Fourth Heart Sound (S4)
Important Note: Almost always pathological in children
- Rare in normal pediatric patients
- When present, suggests diastolic dysfunction
Adult Difference: May be normal in elderly patients due to decreased ventricular compliance
Additional Normal Pediatric Heart Sounds
Physiologic Ejection Sounds
- Common due to more elastic arterial walls
- Closer proximity to chest wall
- Usually heard at pulmonic area
- Diminishes with age
Venous Hums
- Continuous, low-pitched sounds
- Common in children aged 3-8 years
- Best heard in sitting position
- Disappears with jugular compression
Pediatric Heart Murmurs: Classification and Characteristics
Basic Classification of Murmurs
1. Timing Classification
- Systolic Murmurs:
- Ejection Systolic (Diamond-shaped)
- Holosystolic/Pansystolic (Plateau)
- Late Systolic
- Early Systolic
- Diastolic Murmurs:
- Early Diastolic (Decrescendo)
- Mid-Diastolic
- Pre-systolic
- Continuous Murmurs: Throughout systole and diastole
2. Grading of Systolic Murmurs
| Grade | Characteristics |
|---|---|
| I/VI | Very faint, heard only in optimal conditions |
| II/VI | Soft but easily audible |
| III/VI | Moderately loud without thrill |
| IV/VI | Loud with palpable thrill |
| V/VI | Very loud, thrill, audible with stethoscope partly off chest |
| VI/VI | Audible without stethoscope |
Detailed Characteristics of Specific Murmurs
Systolic Murmurs
1. Ejection Systolic Murmurs
Characteristics:
- Crescendo-decrescendo pattern
- Begins shortly after S1
- Peaks in mid-systole
- Common conditions:
- Pulmonary Stenosis: Harsh, upper left sternal border
- Aortic Stenosis: Harsh, right upper sternal border
- Flow Murmurs: Soft, pulmonary area
2. Holosystolic/Pansystolic Murmurs
Characteristics:
- Uniform intensity throughout systole
- Starts with S1, ends at S2
- Common conditions:
- Ventricular Septal Defect (VSD): Harsh, left sternal border
- Mitral Regurgitation: Blowing, apex
- Tricuspid Regurgitation: Lower left sternal border
Diastolic Murmurs
1. Early Diastolic Murmurs
Characteristics:
- High-pitched, decrescendo
- Begins immediately after S2
- Common conditions:
- Aortic Regurgitation: Right upper sternal border
- Pulmonary Regurgitation: Left upper sternal border
2. Mid-Diastolic Murmurs
Characteristics:
- Low-pitched, rumbling
- After opening snap in mitral stenosis
- Common conditions:
- Mitral Stenosis: Apex
- Tricuspid Stenosis: Lower left sternal border
- High-flow states across AV valves
Continuous Murmurs
Characteristics:
- Present throughout systole and diastole
- Common conditions:
- Patent Ductus Arteriosus: Left infraclavicular area
- Arteriovenous malformations
- Coronary fistula
- Venous hum: Normal finding in children
Special Considerations in Pediatric Murmur Assessment
Innocent Murmurs
Common Types:
- Still's Murmur:
- Musical/vibratory
- Left lower sternal border
- Grade 1-3/6
- Common in 3-7 years
- Pulmonary Flow Murmur:
- Soft ejection systolic
- Upper left sternal border
- Common in children and adolescents
- Venous Hum:
- Continuous, more prominent in diastole
- Right supraclavicular area
- Diminishes with neck rotation/compression
Specific Cardiac Conditions and Their Murmurs in Pediatrics
1. Atrial Septal Defect (ASD)
ASD Murmur
Primary Murmur Characteristics
- Type: Ejection systolic murmur
- Location: Left upper sternal border (2nd-3rd ICS)
- Grade: 2-3/6
- Quality: Soft, crescendo-decrescendo
- Associated Sound: Fixed split S2 (hallmark finding)
Additional Auscultatory Findings
- Mid-diastolic flow rumble at lower left sternal border (with large shunts)
- Increased P2 intensity
- Splitting doesn't vary with respiration
Key Distinguishing Features
- Fixed splitting of S2 persists during all phases of respiration
- Flow murmur becomes more prominent with increased flow states
- Right ventricular heave may be present in large defects
2. Ventricular Septal Defect (VSD)
VSD Murmur
Primary Murmur Characteristics
- Type: Holosystolic murmur
- Location: Left lower sternal border (3rd-4th ICS)
- Grade: 3-6/6
- Quality: Harsh, pansystolic
- Radiation: May radiate to right sternal border
Variations by Defect Size
- Small VSD:
- High-pitched, harsh murmur
- No significant hemodynamic effects
- Moderate VSD:
- Louder murmur with thrill
- May have mid-diastolic rumble
- Large VSD:
- Softer murmur due to pressure equalization
- Signs of heart failure may be present
3. Patent Ductus Arteriosus (PDA)
PDA Murmur
Primary Murmur Characteristics
- Type: Continuous "machinery" murmur
- Location: Left infraclavicular area
- Grade: 2-4/6
- Quality: Continuous, crescendo during systole, peaks around S2
- Special Feature: Extends through diastole
Variations with PDA Size
- Small PDA: Soft continuous murmur
- Moderate PDA: Classic machinery murmur
- Large PDA: May only hear systolic component
4. Bicuspid Aortic Valve
Bicuspid Aortic Valve Murmur
Primary Murmur Characteristics
- Type: Ejection systolic murmur
- Location: Right upper sternal border
- Grade: Variable (1-4/6)
- Quality: Crescendo-decrescendo
- Radiation: Carotid arteries
Progressive Changes
- May be silent in early years
- Development of stenosis over time
- Possible late aortic regurgitation
- Click may be present early in systole
5. Pulmonary Stenosis
ASD Murmur
Primary Murmur Characteristics
- Type: Ejection systolic murmur
- Location: Left upper sternal border
- Grade: Varies with severity (1-6/6)
- Quality: Harsh, crescendo-decrescendo
- Associated Sound: Ejection click (unless severe)
Severity Indicators
- Mild:
- Early systolic ejection click
- Short soft murmur
- Moderate:
- Longer murmur
- Delayed peak
- Severe:
- No click
- Long harsh murmur
- Prominent right ventricular lift
6. Aortic Stenosis and Regurgitation
ASD Murmur
Aortic Stenosis Characteristics
- Type: Ejection systolic murmur
- Location: Right upper sternal border
- Grade: 3-6/6
- Quality: Harsh, crescendo-decrescendo
- Radiation: Neck vessels, apex
Aortic Regurgitation Characteristics
- Type: Early diastolic murmur
- Location: Left sternal border
- Quality: High-pitched, decrescendo
- Best Heard: Patient leaning forward, end-expiration
Combined Lesion Features
- Systolic and diastolic murmurs may coexist
- Wide pulse pressure in significant AR
- Possible Austin Flint murmur
- Left ventricular hypertrophy may develop
