Heart Sounds and Murmurs

Heart Sounds

• "Lub-Dub" Sound
  • S1 ("Lub"): Closing of the AV valves after atria pump blood into ventricles.
  • S2 ("Dub"): Closing of the aortic and pulmonary valves, post ventricular ejection of blood.
• Intervals
  • Systole: Time between S1 and S2; ventricles contract.
  • Diastole: Time between S2 and the next S1; ventricles relax and fill with blood. Longer than systole.
• Auscultation Sites: 4 chest wall sites aligned with aortic, pulmonic, tricuspid, and mitral valves.

Heart Murmurs

• Characteristics: Whooshing sounds due to turbulent blood flow.
• Diagnosis
  • Timing: When murmur occurs in cardiac cycle.
  • Intensity Changes: Variation in sound intensity over time.
  • Auscultation Site: Best heard location on the chest.

Systolic Murmurs

Mitral Valve Regurgitation

• Cause: Mitral valve does not close properly; blood surges back to left atrium during systole.
• Sound Pattern: Holosystolic murmur starting at S1, consistent intensity.
• Best Heard: Mitral region (apex), radiating to left axilla.
• Other Features: Quieter S1 due to incomplete valve closure.

Tricuspid Valve Regurgitation

• Characteristics: Similar to mitral regurgitation.
• Best Heard: Tricuspid area, sound radiates along left sternal border.

Aortic Valve Stenosis

• Cause: Aortic valve does not open properly; blood forced through narrow opening.
• Sound Pattern: Crescendo-decrescendo (diamond-shaped) starts shortly after S1 with a possible ejection click.
• Best Heard: Aortic area, radiating to carotid arteries.

Pulmonic Stenosis

• Characteristics: Similar to aortic stenosis.
• Best Heard: Pulmonic area without neck radiation.

Other Conditions

• Ventricular Septal Defect
• Mitral Valve Prolapse

Diastolic Murmurs

Aortic Valve Regurgitation

• Cause: Aortic valve does not close properly; blood flows back during diastole.
• Sound Pattern: Peaks at beginning of diastole, rapidly decreases.
• Best Heard: Along left sternal border.

Other Diastolic Murmurs

• Pulmonic Regurgitation
• Mitral Stenosis
• Tricuspid Stenosis