Systematic Approach:
  • Identify sounds

  • Intensity and variations

  • Splitting? (insp/exp)

    		•  S1
    S2
    S3
    S4
    extra sounds
    Heart Sounds (exhibit)
    Heart Sounds
    S1 - First Heart Sound 
    Produced by: Closure of atrio-ventricular valves
    Auscultation Diaphragm. 'LUB dup'
    Intensity HR, CO, MS, short P-R interval (more common).
    Intensity obesity, MR, long P-R interval.
    Normal Splitting M1 --- T1 (10 to 30 msec). 'T-LUB dup'
    Widened Splitting M1 ------ T1 (complete RBBB).
    Reversed Splitting T1 --- M1 (severe MS, complete LBBB).
    Comments avoid confusing it with the opening snap.

    S2 - Second Heart Sound 
    Produced by: Closure of aortic and pulmonary valves
    Auscultation Diaphragm. 'lub DUP'
    A2 Intensity Systemic HTN
    P2 Intensity Pulmonary HTN
    Normal Splitting A2 --- P2 (aortic component is louder). 'lub T-DUP'
    Physiologic Splitting A2 --- P2 (normal in inspiration not expiration).
    Widened Physiologic Splitting A2 ------ P2 (complete RBBB, PS).
    Fixed Splitting A2 ---- P2 (RBBB, PS, ASD).
    'Paradoxic' (reversed) Splitting P2 --- A2 (maximum in expiration, not in inspiration. LBBB, AS, systemic HTN).
    Comments  
    S3 - Third Heart Sound 
    S3 Ventricular Gallop (diastolic)
    cardiac cycle Proto-diastolic (0.14 to 0.16 seconds after A2).
    character Low-pitched sound (end of rapid filling)
    Auscultation Bell (after coughing). S1---S2 -S3
    'lub duppa'
    Left S3 = apex, expiration, left lateral decubitus.
    Right S3 = left sternal border or xiphoid, inspiration.
    Comments Normal in young people. Indicates ventricular decompensation. Worst prognosis than S4.

    S4 - Fourth Heart Sound 
    S4 Atrial Gallop (presystolic)
    cardiac cycle Tele-diastolic. produced by a strong left atrial contraction in Patients with decreased left ventricular compliance.
    character Low-pitched, dull sound.
    Auscultation Bell. S4-S1---S2
    'daLUB dup'
    Left S4 = apex, expiration, left lateral decubitus. Accompanied by palpable presystolic impulse of the left ventricle (MI, systemic HTN, HCM, anemia, thyrotoxicosis).
    Comments Normal in young people. Indicates ventricular decompensation. Worst prognosis than S4.


    EXTRA SOUNDS
    Extra Sounds

    Heart Sounds (cardiac cycle)