Abnormal heart sounds are auditory findings beyond the normal S1 and S2 heart sounds. They play a crucial role in diagnosing various cardiovascular conditions.

Types of Abnormal Heart Sounds

Extra Heart Sounds

S3 (Third Heart Sound)

• Occurs in early diastole
• Low frequency sound
• Best heard at the cardiac apex
• Can be physiological in children and adolescents
• May indicate diastolic volume overload in conditions like heart failure

S4 (Fourth Heart Sound)

• Occurs in late diastole
• Soft, low frequency sound
• Best heard at the cardiac apex
• Often indicates atrial contraction against elevated left ventricular pressure

Murmurs

Heart murmurs are abnormal sounds caused by turbulent blood flow. They can be classified as:

• Systolic murmurs: Occur during ventricular contraction
• Diastolic murmurs: Occur during ventricular relaxation
• Continuous murmurs: Occur throughout the cardiac cycle

Common causes of murmurs include:

• Valve stenosis or regurgitation
• Septal defects
• Increased blood flow through normal valves

Mechanisms of Abnormal Heart Sounds

1. Normally silent events becoming audible (e.g., valve opening sounds)
2. New abnormal events in the heart (e.g., mitral valve prolapse click)
3. Incorrect timing of normal cardiac events (e.g., abnormal splitting of S2)

Diagnostic Approach

• Careful auscultation at different locations on the chest
• Consideration of timing, intensity, and radiation of sounds
• Echocardiogram for detailed evaluation
• Additional tests may include chest X-ray, ECG, or cardiac catheterization

Clinical Significance

Abnormal heart sounds can indicate various conditions, including:

• Valve disorders (stenosis, regurgitation)
• Congenital heart defects
• Cardiomyopathies
• Heart failure

It’s important to note that not all murmurs are pathological. Innocent murmurs can occur, especially in children, and may not require treatment.