Completed - Normal Second heart sound

The most difficult thing in auscultation is to identify the abnormalities of S2.

Physiology of Second heartsound

Two components for 2nd heart sound are- aortic and pulmonary
Aortic component it is the 1st component and loud one   heard in all areas
Pulmonary component - 2nd component and soft, heard only over pulmonary area.

Normal second heart sound

1. It is a high pitched sound with normal split - 2 components are separately heard during inspiration and as single component during expiration over the pulmonary area.
2. Distance between the 2 components during inspiration is 0.04 sec, during expiration is 0.02 sec. 
3. Human ear can appreciate, when the distance between the 2 components is 0.03 or more. 
4. Normal second heart sound is expressed as - normal in intensity and normal split with respiration.

Things to look for in S2:

Intensity
Splitting
A2 heard over aortic area and pulmonary area and the apex.
P2 heard over pulmonary area and 2-4 LICS only and not at the apex.
P2 heard over the apex only in pulmonary artery hypertension and in young.
Best site for S2 in COPD—epigastrium

What is Gallop rhythm

3 sounds heard during each cardiac cycle produce triple rhythm

Triple rhythm with sinus tachycardia produce Gallop rhythm imitating the sounds of galloping horse.
LV S3 gallop - is an important auscultatory sign of Left ventricular failure.
LVS3 is a sign of systolic dysfunction of ventricle.
Early S3 is heard in RVEMF -this is due to sudden limitation of ventricular filling.
Pericardial knock - An early S3 in constrictive pericarditis as in RV EMF.

S3 gallop is common in:

1. Dilated cardiomyopathy.
2. Decompensated aortic valve disease.
3. Decompensated hypertensive heart disease.

RV S3 is always pathological
It is heard at LLSB.
Inspiratory augmentation is  present.
This is  associated with tricuspid regurgitation.

Atrial gallop S1,S2, S4
Ventricular gallop S1, S2, S3

Quadruple Rhythm
Quadruple rhythm is the presence of 4 heart sounds
(S1, S2, S3 and S4).

Summation Gallop
Summation is the presence of S1,S2 with merged S3 and S4

Causes of fourth heartsound

 LV S4  causes

1. Systemic hypertension
2. AS (left ventricular hypertrophy)
3. LV myocardial infarction

RVS4  causes

1. Pulmonary hypertension
2. Pulmonary stenosis (Right Ventricular hypertrophy)
3. RV myocardial infarction.

Features of RVS4

1. Heard at LLSB
2. Inspiratory augmentation present
3. Associated with  a wave in JVP
4. Seen in PAH and pulmonary stenosis

Triple rhythm
S1+S2+S3/S4

Quadruple rhythm
S1,S2 + S3 + S4.

Seen In:

• Cardiomyopathy
• Coronary artery disease

Summation gallop
S, S3 with merged S, & S4.

Causes of pathological S4

1. Hypertrophic cardiomyopathy
2. Systemic hypertension
3. Coronary artery disease
4. Myocardial infarction
5. Ventricular aneurysm.

S3 -Ventricular distension sound.
S4 -Atrial contraction sound.

Achronym

LV : Left Ventricular

AS : Aortic Stenosis

RV : Right Ventricular

S1 - First Heart Sound

S2 - Second Heart Sound

S3 - Third Heart Sound

S4 - Fourth Heart Sound

Third heart sound

S3 is a low pitched sound produced due to rapid deceleration of blood during inflow Into the leftventricle.It is also called as protodiastolic sound or ventricular gallop.S3 signifies diastolic overload of the ventricles. It occurs during the first rapid filling phase of cardiac cycle (in ventricular diastole).
Mechanism of S3 
More than normal amount of blood reaching the ventricle during rapid filling phase, produce stretch on myocardium - tense chordae and papillary muscle, it will produce S3
Pathogenesis of S3
Abnormally increased LVEDV due to increased transvalvular flow or diminished LV function.
Characteristics of S3

• Low pitched sound
• 0.12 sec after S2 in produced both in LV and RV

Physiological 3rd heart sound seen in children and adults upto 30 - 35 yrs.
Physiologic S3 is associated with functional murmur and venous hum and it disappears in standing position
What are the association of S3?
S3 commonly associated with the following

• Pulsus alternans 
• Narrow pulse pressure
• Heaving apex
• Other signs of LV/RV failure

Causes of third heartsound

Etiology of S3
Abnormal increase in transmitral flow

• Mitral regurgitation
• VSD
• PDA

Depression of ventricular function

• LV dysfunction—LV S3
• RV dysfunction—RV S3
• LV S3 and RV S3

LV S3 may be either physiological or pathological
RVS3 is always pathological.
Causes of physiological S3 

• Children
• Young adults (< 40 years)
• Athletes
• Pregnancy.
• Pathological 3rd heart sound
• Pathologic S3 persists in the standing position and is associated with other signs of LV dysfunction.
• LV S3 - MR, LVF
• RV S3 - TR, RV

Causes of pathological S3

• High output states
• Congenital heart diseasis ASD, VSD,
• Regurgitant lesions of aortic, mitral, tricuspid valves.
• Hypertrophic cardiomyopathy
• ischaemic heart diseases
• Constrictive pericarditis
• Systemic hypertension
• Pulmonary hypertension

Differentiating Features between Right and Left Ventricular S3
RV-S3                                              LVS3
Tncmpid area                                      MItral area
Increas esOn inspiration                  Increases on expiration

Causes of Fourth heartsound

Left ventricular S4 (LVS4)

• Systemic hypertension
• AS (left ventricular hypertrophy)
• LV myocardial infarction

Right ventricularS4 (RVS4)

• Pulmonary hypertension
• Pulmonary stenosis (Right Ventricular hypertrophy)
• RV myocardial infarction.

Features of Right ventricularS4(RVS4)

• Heard at LLSB
• Inspiratory augmentation^
• Associated with  a wave in JVP
• Seen in PAH and pulmonary stenosis

Triple rhythm-S1+S2+S3/S4
Quadruple rhythm-S1, S2 + S3 + S4.
Seen In:

• Cardiomyopathy
• Coronary artery disease

Causes of pathological S4

• Hypertrophic cardiomyopathy
• Systemic hypertension
• Coronary artery disease
• Myocardial infarction
• Ventricular aneurysm.
• S3 Ventricular distension sound
• S4 Atrial contraction sound.

Causes of shock or Palpable heart sounds

Shocks are palpable equivalents of heart sounds.
Area                                        Shock                                              Cause
Aortic area                            A2/ Aortic ejection click               Systemic hypertension
                                                                                                         Congenital valvularnaortic stenosis                                                                                                                 Aortic root dilatation                              
                                                                                                                                                                               Pulmonary area                  P2/pulmonary ejection click             Pulmonary hypertension
                                                                                                          Pulmonary valvular stenosis
                                                                                                          Pulmonary artery dilatation
Apical                                      S1                                                  Mitral stenosis
                                             Opening snap                                       Mitral stenosis                                                                                              S3                                                  DCM
                                                     S4                                                  HOCM