Heart Auscultation

Watch 👉 Heart Sounds

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Watch 👉 Heart Murmurs

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Anatomical locations and auscultatory sites for heart valves (I–IV: anatomical locations of heart valves)

Anatomical locations and auscultatory sites for heart valves (I–IV: anatomical locations of heart valves)

Heart Sounds Overview

Heart Sound	Features & Associated Pathology
S3	🔹 Heard just after S2
🔹 Caused by reverberant sound as blood fills an enlarged LV cavity during passive diastolic filling
🔹 Heart failure with reduced EF
🔹 High-output states (e.g., thyrotoxicosis)
🔹 Mitral or aortic regurgitation
S4	🔹 Heard just before S1
🔹 Caused by blood striking a stiff LV wall during atrial contraction
🔹 Concentric LV hypertrophy
🔹 Restrictive cardiomyopathy
🔹 Acute myocardial infarction

<aside> ❓

What abnormal heart sound is often heard during the acute phase of myocardial infarction?

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S4
- Often referred to as "ten-nes-see" a sound
- Which corresponds to S4-S1-S2
S3
- Often referred to as "ken-tuc-ky" a sound
- Which corresponds to S1-S2-S3 </aside>

Inspiration → drop in intrathoracic pressure → ↑ venous return → ↑ RV filling → ↑ RV stroke volume → ↑ RV ejection time → delayed closure of pulmonic valve.
↑ pulmonary impedance (↑ capacity of the pulmonary circulation → accomodates more blood → less blood going to the left atrium) also occurs during inspiration, which contributes to delayed closure of pulmonic valve.

Physiologic Splitting - Audio (Recommended)

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Seen in conditions that delay RV emptying (e.g., pulmonic stenosis, right bundle branch block).
Causes a markedly delayed pulmonic sound in relation to aortic sound (especially on inspiration).
An exaggeration of normal splitting.

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Heard in ASD.
ASD → continuous left-to-right shunt → continuously ↑ RA and RV volumes → continuously ↑ flow through pulmonic valve → continuously delayed pulmonic valve closure (independent of respiration).

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