Heart Sounds & Types

1. Introduction:
2. Normal Heart Sounds
   1. First Heart Sound (S1– “Lub”)
   2. Second Heart Sound (S2– “Dub”)
3. How to Listen to the Heart Effectively
4. Abnormal Heart Sounds
5. Heart Murmurs: What Do They Mean?
   1. Types of Murmurs
6. Complete Cardiac Examination Besides auscultation:
7. Heart Sounds and Common Heart Conditions Heart Failure:
8. Recording and Documenting Findings Good documentation includes:
9. Conclusion

Introduction:

Why Heart Sounds Matter
Listening to heart sounds with a stethoscope is called cardiac auscultation. It is essential, low-cost, and non-invasive. This method helps to understand how the heart works. Even though modern machines like echo cardiograms are available, heart sounds still help in quick diagnosis and decision-making. By carefully listening, doctors can catch problems in heart valves, blood flow, or heart function early.

Normal Heart Sounds

First Heart Sound (S1– “Lub”)

The first heart sound is known as S1. It occurs when the heart’s two AV valves close.

These valves are the mitral and tricuspid valves. It happens just after the ventricles start contracting (after the QRS wave on ECG).

The mitral valve usually closes a little before the tricuspid, but they are generally heard as one sound.

It is a lower pitch and longer than the second heart sound (S2).

A loud S1 can occur in mitral stenosis; a soft S1 may mean mitral regurgitation or first-degree atrioventricular block.

Second Heart Sound (S2– “Dub”)

S2 is heard when the semilunar valves (aortic and pulmonary) close.

It occurs after the T wave on ECG, marking the start of relaxation (diastole).

Aortic valve closure (A2) comes before pulmonary valve closure (P2).

S2 is higher in pitch and shorter than S1.

Normal S2 splits during inspiration (A2 then P2).

Wide or fixed splitting helps diagnose diseases such as the right bundle branch block and pulmonary stenosis. Paradoxical splitting helps in diagnosing issues like atrial septal defect or aortic stenosis.

How to Listen to the Heart Effectively

Stethoscope Use:

Use the diaphragm for high-pitched sounds (S1, S2, most murmurs).

Use the bell lightly for low-pitched sounds (S3, S4, mitral stenosis).

Best Listening Areas:

Aortic: 2nd right intercostal space.

Pulmonic: 2nd left intercostal space.

Erb’s point: 3rd left intercostal space.

Tricuspid: 4th left intercostal space.

Mitral (Apex): 5th left intercostal space at midclavicular line.

Patient Positions:
Supine, sitting, leaning forward, or left lateral can enhance different sounds.
Steps:
1. Listen to all areas using the diaphragm, then the bell.
2. Focus on S1 and S2.
3. Check for extra sounds (S3, S4, clicks, snaps, murmurs).
4. Use maneuvers (like Valsalva or squatting) to change sound intensity and identify
conditions.

Abnormal Heart Sounds

Third Heart Sound (S3– “Ventricular Gallop” )
Heard right after S2 during early diastole.
Normal in young people and pregnant women.
In older adults, it suggests heart failure or volume overload.
Best heard with the bell at the apex in the left lateral position.
Fourth Heart Sound (S4– “Atrial Gallop” )
Heard just before S1, diastole.
Almost always abnormal—indicates stiff ventricles (e.g., in hypertension, aortic stenosis).
Not heard in atrial fibrillation.
Best heard at the apex with the bell.

Systolic Clicks
High-pitched sounds during systole.
Ejection clicks: early systole (e.g., aortic/pulmonary stenosis).
Non-ejection clicks: mid-to-late systole (often from valve prolapse).
Pericardial Rubs
Scratchy, high-pitched sounds from an inflamed pericardium.
Best heard when the patient leans forward.
Seen in acute pericarditis.

Heart Murmurs: What Do They Mean?

Heart murmurs are longer sounds. They are caused by turbulent blood flow. This is usually due to valve issues or abnormal pathways in the heart.

Types of Murmurs

1. Systolic Murmurs (Between S1 and S2):
Ejection murmurs: Crescendo-decrescendo. Seen in aortic or pulmonary stenosis.
Regurgitant murmurs: Constant (holosystolic), due to leaky valves (e.g., mitral/tricuspid
regurgitation).
Late systolic murmurs: Often caused by mitral valve prolapse (follows a click).

2. Diastolic Murmurs (Between S2 and next S1):
Early diastolic: Aortic or pulmonary regurgitation.
Mid-diastolic: Mitral or tricuspid stenosis (often includes an opening snap).
Late diastolic (presystolic): Seen in mitral stenosis due to atrial contraction.

3. Continuous murmurs:
Heard throughout systole and diastole.
Example: Patent ductus arteriosus (machine-like murmur).

Complete Cardiac Examination
Besides auscultation:

Observe: Breathing, color, swelling, jugular veins.
Check vitals: BP, heart rate, oxygen, temperature.
Palpate:
PMI (Apex beat): Displacement may suggest an enlarged heart.
Heaves: Indicate hypertrophy.
Thrills: Vibrations suggest loud murmurs.
Pulse Check: Rate, rhythm, strength.
Jugular venous pressure: Shows fluid status.
Peripheral signs: Edema, pulse asymmetry, bruits (vascular noises).

Heart Sounds and Common Heart Conditions
Heart Failure:

S3: Common in systolic failure.
S4: Common in diastolic failure.
Regurgitation murmurs may appear.
Congenital Heart Defects:
Murmurs from abnormal connections (VSD, ASD, PDA).
Changed S2 splitting patterns.
Ejection clicks from valve defects.
Pericardial Diseases:
Pericarditis: Friction rub.
Effusion: Dull heart sounds.
Constrictive Pericarditis: Early diastolic knock.

Recording and Documenting Findings
Good documentation includes:

Timing (systolic/diastolic).
Pitch (low, medium, high).
Quality (blowing, harsh, rumbling).
Location and radiation.
Intensity (graded 1 to 6 for systolic; 1 to 4 for diastolic).
Shape (crescendo, decrescendo, plateau).
Abnormal sounds: Describe timing, pitch, and position.

Conclusion

Learning to listen to heart sounds is a vital skill. Even with new technology, the power of a skilled ear and stethoscope. Understanding what you hear and connecting it to patient symptoms helps in early and accurate diagnosis, improving patient care significantly.