heart sounds

[SAcreed]

Heart Sounds
1. Auscultation sites
2. Auscultation order
3. Heart sounds: S1, S2, splitting
4. Added sounds: S3, S4, opening snap, systolic click
5. Murmurs: general considerations, grading

Auscultation sites

• Aortic: 2nd right intercostal space.
• Pulmonary: 2nd left intercostal space.
• Tricuspid: 4th intercostal space, at lower left sternal border.
• Mitral: 5th left intercostal space, 1 cm medial to midclavicular line.

Auscultation order
• Mitral: bell.
• Mitral diaphragm.
• Tricuspid.
• Aortic.
• Pulmonary.

1st heart sound

Sound:
Where:
Why: mitral, tricuspid valves shutting.
Loud DDx: Mitral stenosis.
Soft DDx: MR.

2nd heart sound
Sound:
Where:
Why: 2 parts: aortic then pulmonary valves shutting [A2, P2].
Loudness of a component tells it shut with high pressure, so HTN there in circuit.
Aortic component loud DDx: Aortic HTN.
Pulmonary component loud DDx: Pulmonary HTN.
Soft DDx: AR, Calcification of aortic valve.

Splitting
Sound:
Why: either aortic valve shut early or pulmonary shut late.

Increased normal splitting [wider split when inspire] DDx: Delayed RV emptying (pulmonary stenosis, RBBB).

Fixed wide splitting DDx: ASD.

3rd heart sound
Sound: in early-mid diastole, low-pitched, "gallop sounding".
Where: apex, louder on expiration.
Why: ventricular distension, may be normal.
DDx:
• Normal in children
• Constrictive pericarditis.
• Mitral regurgitation
• Tricuspid regurgitation
• LVF, RVF

4th heart sound
Sound: higher pitch, late diastole, "gallop sounding"
Where:
Why: ventricular filling resistance, always pathologic.
DDx:
• HTN
• MI
• AS
• Heart block

Opening snap
Sound: high-pitched click after S2.
Where: lower L sternal edge.
Why: stiff mitral valve suddenly opened.
DDx:
• Mitral stenosis.

Systolic click
Sound: high-pitched click, soon after S1. Click followed by AS or PS murmur.
Where: aortic, pulmonary ausc sites.
Why: stiff aortic valve suddenly opened.
DDx:
• AS.

Murmurs: general considerations
Can be either systolic or diastolic. we will only hear systolic.
Mnemonic for whether murmur is systolic diastolic:
PASS and PAID:
Pulmonary, Aortic Stenosis = Systolic.
Pulmonary, Aortic Insufficiency = Diastolic.
Then mitral and tricuspid must be opposite to these.

Murmurs: grading
Graded on scale of 1 to 6.
1. Only cardiologist can hear.
2. Trained doctor can hear.
3. Student can hear. No thrill.
4. Thrill barely palpable.
5. Thrill easily palpable.
6. Can hear murmur by being in the room without a stethoscope.