This document discusses how to use a stethoscope to listen to heart sounds and identify different types of sounds. It describes the two sides of the stethoscope - the bell for low tones and the diaphragm for high tones. There are normally two main heart sounds, S1 and S2, which correspond to valve openings and closings in the cardiac cycle. Additional sounds like S3 and S4 can indicate medical conditions - S3 often suggests heart failure while S4 may suggest hypertension. The document provides details on the timing, causes and locations for optimal auscultation of each type of heart sound.

1. Clinical skills
1. The Stethoscope
 The Bell
 is used to hear low-pitched sounds
 used for mid-diastolic murmur of mitral stenosis or S3 in heart failure
 The Diaphragm
 filters out low-pitched sounds highlights high-pitched sounds
 used for analyzing the second heart sound, ejection and midsystolic clicks and for the
soft but high-pitched early diastolic murmur of aortic regurgitation
2. Heart Sounds
 The mechanical activities of the heart during each cardiac cycle, cause the production of
some sounds, which are called heart sounds
 Factors involved in the production of heart sounds
 1.The movement of blood through chambers of the heart
 2.The movement of valves of the heart.
 3.The movement of cardiac muscle.
3. What we hear ?
 We have all heard the heart make the usual sounds
 LUB----------DUB •
 Lub is the first sound or S1
 Dub is the second heart sound or S2
4. First heart sound S1
 First heart sound S1 The “lub” in the lub – dub
 The 1st heart sound, marks the beginning of systole (end of diastole)
 This sound is primarily because of the
 closing of the mitral and tricuspid valves
 Anatomically they are located
 between the atria and the ventricles
 Loudest at the cardiac apex
 Time: 0.14 sec
 Causes:
 It mainly occurs due to sudden
 closure of atrioventricular valves
 The first heart sound can usually be heard easily with both the bell and the diaphragm
5. Second heart sound
 Second heart sound S2
 S2 is the “dub” in the lub- dub
 The 2nd heart sound, marks the end of systole (beginning of diastole).
 The sounds are because of the
 closing of the Pulmonic and Aortic valves
 This is the end of systole

2.  Loudest at the base of the heart
 May have a split sound
 Duration: 0. 11 sec
 base S2 louder than S1
 Apex S1 louder than S2
 Causes: It mainly produces during
 sudden closure of the semilunar valves
 For the second heart sound the diaphragm is invaluable, with the stethoscope usually
best placed at the base
6. Third heart sound
• Third heart sound also called a ventricular gallop
• Caused by rush of blood from Atria to Ventricle during rapid filling phase of Cardiac Cycle.
• It occurs at the middle third of diastole after S2.
• The third heart sound may present in childrens, some trained athletes, and sometimes in
pregnancy
• The commonest causes are left ventricular failure and mitral regurgitation
• • It is best heard with the bell-side of the stethoscope at the apex of the heart .
• Time: 0.1 sec
7. fourth heart sound
• S4 fourth heart sound called a atrial gallop.
• Occurs at the last one third of Diastole Just before S1
• Produced due to Atrial contraction which causes rapid flow of blood from Atria to Ventricle and
vibration in the blood.
• It is a sign of a pathologic state, (left ventricular hypertrophy, hypertension, aortic stenosis)
• It is best heard with the bell-side of the stethoscope at the apex of the heart .
8. Here is where you expect to hear the various sounds
 LUB-- DUB-------------LUB—DUB
 S1 S2 S3 S4 S1 S2
 Heart Sounds
 • S1 – onset of the ventricular contraction
 • S2 – closure of the semilunar valves
 • S3 – ventricular gallop
 • S4 – atrial gallop

3. 9.