[CK] Physical S3 vs S4

Third Heart Sound S3

Description:
Low frequency sound in early diastole, 120 to 180 ms after S2

Sounds like:
Lub du bub S1S3S2 cadence similar to "Kentucky"

Clinical Significance:
Results from increased atrial pressure leading to increased flow rates, as seen in congestive heart failure, which is the most common cause of a S3. Associated dilated cardiomyopathy with dilated ventricles also contribute to the sound. See Accuracy in Diagnosis of CHF .

Less commonly, valvular regurgitation and left to right shunts may also result in a S3 due to increased flow.

May be normal physiological finding in patients less than age 40.

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Fourth Heart Sound S4

Description:
Low frequency sound in presystolic portion of diastole,

Sounds like:
Belub dup S1S4S2 cadence similar to "Tennessee"

Clinical significance:
Seen in patients with stiffened left ventricles, resulting from conditions such as hypertension, aortic stenosis, ischemic or hypertrophic cardiomyopathy.

In patient with mitral regurgitation, suggestive of acute onset of regurgitation due to the rupture of the chorda tendinae that anchor the Valvular leaflets.

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S3: normal <40, CHF with higher atrial pressure(VOLUME DUMPING - earlier)

(Ken TucKy)

S4: not normal, Stiffness(d/t MI, AS, HTN, hCMP) 

with acute MR, flash pulmonary edema => EMERGENT SIGN OF ACS!(Significant with vascular surgeon) 

(Tene see)