Sign in Subscribe
Education

Heart Sounds

mLpenguin

• 2 min read
Heart Sounds
Photo by Etactics Inc / Unsplash

Sounds

TPAM

S1 - Closing of the mitral and tricuspid valves just after the beginning of systole

S2 - Low-pitched sound caused by the closing of the aortic (A2) and pulmonic (P2) valves at the beginning of diastole

S3- Rapid filling of the ventricles during early diastole, when blood enters the ventricle quickly

  • "Ken-tuck-y"
  • It can be a normal finding in children, young adults, and pregnant women
  • Increase early LV filling
    • Acute ventricular failure or severe aortic or mitral regurgitation

S4 is caused by increased ventricular filling during atrial contraction, occurring in patients with decreased ventricular compliance.

  • "Tenn-e-ssee"
  • Increased resistance to ventricular filling due to high atrial pressure or a stiff ventricle
  • Ischemic heart disease, AS, HCM, diabetic cardiomyopathy, and hypertensive heart disease with concentric hypertrophy

Paradoxical splitting of S2

  • The pulmonic valve closes before the aortic valve, resulting in the split sound being heard during expiration and disappearing during inspiration.
    • Delay in aortic valve closure
  • Causes:
    • Left Bundle Branch Block (LBBB)
    • Aortic Stenosis
    • Wolff-Parkinson-White (WPW) Syndrome
    • Severe Left Ventricular Dysfunction
    • Hypertrophic Obstructive Cardiomyopathy (HOCM)

Systolic

Crescendo-decrescendo

  • Radiates to neck (carotids) and apex -> Aortic Stenosis
    • Worse with ↑ venous return - More blood flowing through aortic valve
    • "Parvus et tardus" - a weak (parvus) and slow-rising (tardus) pulse
    • Soft and single S2 during inspiration
  • ↓ venous return (e.g.,Valsalva) -> increases murmur (less blood flow keeping LVOT open) -> HOCM
  • Musical quality -> increases when supine vs sitting -> Still murmur
    • Benign

Holosystolic

  • Worsens with inspiration (↑ venous return) -> Tricuspid regurgitation
    • Radiates to the right sternal border
  • Worsens with exhalation (↓ venous return) -> Mitral regurgitation
    • Radiates to the axilla
  • Harsh-sounding/Blowing -> Ventricular septal defect (VSD)

Diastolic

Late crescendo (Mid-systolic click)

  • Mitral valve prolapse
    • Opening snap with middiastolic rumble at cardiac apex
    • Early diastolic sound followed by a middiastolic murmur
    • ↑ TPR (e.g.,squatting, hand grip) - decreases murmur

High-pitched blowing heard at the end of expiration

  • Early decrescendo
  • Aortic regurgitation (insufficiency)
    • Blowing
    • Widened pulse pressure:
      • Pulse Pressure = Systolic BP - Diastolic BP
        • Normal pulse pressure: ~30-40 mmHg
        • Widened pulse pressure: >40 mmHg)
      • Water hammer/Corrigan pulse
    • Bounding pulses
      • Left lateral decubitus causes an increased pounding sensation

Opening snap in early diastole after A2 

  • Tensing of chordae tendinae
  • Late (diastolic) rumble heard at the apex 
  • Mitral Stenosis

Continuous machine like (constant) murmur

  • Patent ductus arteriosus (PDA)

A fixed split S2

  • Systolic and diastolic
  • Atrial septal defect (ASD)
    • abnormal flow increases right ventricular filling throughout the respiratory cycle, resulting in a constant delay in pulmonic valve closure

A paradoxically split S2

  • Delay of aortic valve closure (A2), with P2 occurring before A2
  • AS or severe HCM

Benign Murmur

Due to turbulent blood flow from the transition from fetal to postnatal circulation

  • Soft intensity (Grade 1-2)
  • Low pitched
  • Musical quality -> Still murmur
  • Early/mid-systolic
  • Decreases/disappears with standing or Valsalva