Heart sound 2 new

What produces Second Heart Sound (S2)?

Aortic (A2) valve closure + Pulmonic (P2) valve closure

What is splitting of S2?

Time gap between A2 and P2 closure

Which component of S2 varies with respiration?

P2 position

Changes of P2 as per respiration

• On expiration - Early closure of P2

• On inspiration - late closure of P2

What is physiological splitting of S2?

Splitting between A2 and inspiratory P2 of about 30 msec

When does P2 occur during inspiration?

Late P2

When does P2 occur during expiration?

Early P2

Best site to auscultate physiological splitting of S2?

Erb’s point

Which side of chest is used to hear S2 splitting?

Left side of chest

Intercostal space for hearing S2 splitting?

3rd intercostal space

Phase of respiration when S2 splitting is best heard?

Inspiration

Normal size of aortic valve orifice?

3–4 cm²

Severe aortic stenosis valve area?

Less than 1 cm²

Why is A2 delayed in aortic stenosis?

Narrow aortic valve causes delayed blood exit

Cause of delayed A2 closure in AS?

Prolonged left ventricular ejection time

Causes of valvular aortic stenosis

• Bicuspid aortic valve (infants)

• Rheumatic fever

• Valve calcification (>65 years)

Why narrow splitting in aortic stenosis?

S2 = A2P2

• first A2 close and the P2 closes

• In aortic stenosis, A2 is delaying as per condition

• This will cause narrowing of s2 / narrow splitting S2

• In severe cases, single S2 is heard and sometimes P2A2 (reverse splitting) can also heard

• Severity depend on time ( early - narrow splitting, late - single s2, severe - reverse splitting )

Mnemonic for clinical findings of aortic stenosis?

SAD

What does S in SAD stand for?

Syncope on exertion

What causes syncope in AS?

Fixed cardiac output during exertion

What does A in SAD stand for?

Angina

Cause of angina in AS?

Aortic stenosis →LV hypertrophy → increased O₂ demand

What does D in SAD stand for?

Dyspnea on exertion

Cause of dyspnea in AS?

Increased LV end-diastolic pressure → pulmonary congestion

Characteristic pulse in aortic stenosis?

Pulsus parvus et tardus/ anacrotic pulse ( slow rising with low amplitude pulse)

Meaning of pulsus parvus et tardus

Slow rising pulse + low amplitude

Type of apex beat in AS?

Heaving apex beat ( due to left side hypertrophy )

What is heaving beat?

forceful beat that can lift your finger

Cause of heaving apex beat in AS?

Left ventricular hypertrophy

What special apical impulse is seen in AS?

Double apical impulse ( due to both LVH and LAH )

Apex beat position in AS?

6th intercostal space (normally in 5th intercostal space )

Apex beat finding in aortic stenosis

• heving beat

• Double apical impulse

• Displacement of apex beat to 6th space

Type of S2 splitting in aortic stenosis?

Narrow split S2

A2–P2 gap in AS?

Less than 30 msec

When does single S2 occur in AS?

Severe AS with simultaneous A2 and P2 closure

What is reverse splitting of S2?

A2 closes after P2

Cause of reverse split S2 in AS?

Worsening severity of AS

Additional heart sound in AS?

Atrial gallop (S4)

Best instrument to hear atrial gallop?

Bell of stethoscope

Type of murmur in AS?

Ejection systolic (crescendo–decrescendo) murmer

Murmer in aortic stenosis present in

systole

Which word in question directly find aortic stenosis?

carotid thrill

Where is thrill felt in AS?

Carotid artery

Investigation of choice for AS?

Transthoracic echocardiography (TTE)

Definitive treatment option for AS?

Transcatheter Aortic Valve Implantation (TAVI)

Why balloning is contraindicated AS manageent?

it will break valve because of calcification

Which test is contraindicated in severe AS

tredmill test ( because low output → syncope)

What is Patent Ductus Arteriosus (PDA)?

Persistent connection between pulmonary artery and aorta

Why left ventricle is failing in PDA?

Most blood is bypassing RV. Due o connection, blood is going to pulmonary artery and then to LA→LV

Origin of ductus arteriosus?

Bifurcation of pulmonary artery

Termination of ductus arteriosus?

Beginning of descending aorta

Normal time of ductus arteriosus closure?

Starts at 10–15 hours after birth

Functional closure of ductus arteriosus by?

Day 7 of life

Type of shunt in PDA?

Left to right shunt

Which ventricle fails in PDA?

Left ventricle

Why LV failure occurs in PDA?

Volume overload of left heart

Direction of blood flow in PDA?

Aorta → Pulmonary artery → Lungs → Left heart

S2 finding in PDA?

Narrow split S2 (because delay in aortic valve closure)

Reason for delayed A2 in PDA?

Prolonged blood exit time

Characteristic murmur of PDA?

Machinery / continuous murmur

Timing of PDA murmur?

Heard in systole and diastole

Peak of PDA murmur?

At S2

Cause of PDA in preterm babies?

Hyaline membrane disease

Mechanism of PDA in preterm infants

Hyaline membrane disease→Hypoxia → ↑ PGE₂ → PDA

Cause of PDA in term babies?

Congenital rubella syndrome

Difference in continuous /machinery and cresendo-decresendo murmer?

Continuous murmer peak at S2 and present in both systole and diastole

Cresendo decresendo presnet only in systole

Clinical features of PDA in babies

• Poor feeding |

• Irritability |

• Dyspnea during breastfeeding

Diagnostic test for PDA?

TTE (tranbsthoracic echo)

Treatment of PDA in preterm babies

Ibuprofen or Indomethacin IV

Treatment of PDA in term babies

Surgical ligation

Complications of PDA

• Pulmonary hypertension |

• NEC |

• CHF |

• AKI

Severe Complication of PDA

eisenmenger syndrome

Causes of narrow split s2

• Aortic stenosis

• Hypertrophic cardiomyopathy ( subvalvular AS)

• Left ventricle failure →

1. Anterior wall MI

2. Myocarditis

3. Wet beri beri ( with pulmonary edema )

4. PDA

5. Severe anemia

Causes of mitral valve regurgitation

• mitral valve prolapse

• Infectiveendocarditis

• Myocardial ischemia

Pathophysiology of MR

blood leak in left atria → less blood pumped to aorta

Examination finding of MR

• S2 wide split

• Pansystolic murmer

Why wide spllit murmer in MR?

• less blood come in ventricle → less time to exit blood →early A2 closure

Most common congenital heart disease in infants?

Ventricular septal defect

Type of shunt in VSD?

Left to right shunt

Cause of shunt in VSD?

LV pressure > RV pressure

Effect of VSD on aortic output?

Reduced blood pumped to aorta

S2 finding in VSD?

Wide split S2 ( less blood - less time )

A2–P2 gap in VSD?

More than 30 msec

Reason for early A2 in VSD?

Less blood exit time

Most common type of VSD?

Perimembranous VSD

Types of VSD

• Perimembranous VSD

• Muscular VSD

• Supracristal VSD

VSD with spontaneous closure?

Muscular VSD ( close till 3rd birthday)

VSD associated with aortic regurgitation?

Supracristal VSD

Pressure nature of ASD?

Low pressure shunt

Pressure difference between left and right atrium

4 mmhg

Which ventricle fails in ASD?

Right ventricle (due to volume overloading)

S2 finding in ASD?

Wide fixed split S2 ( delayed pulmonary closure and early A2 closure)

Why no physiological splitting in ASD?

Same RV filling during inspiration and expiration

Most common age of ASD presentation?

5 years

Adult presentation of ASD?

Rare

ASD diffrenece in inspiration and expiration

Feature	Normal – Inspiration	Normal – Expiration	ASD – Inspiration	ASD – Expiration
Venous return to right heart	↑↑ Increased	↓↓ Decreased	↑↑ Increased	↓↓ Decreased
Inter-atrial pressure difference	-	-	No pressure difference	Pressure difference develops
Inter-atrial shunting	-	-	❌ No shunt	✅ LA → RA shunt
Right ventricular filling	Increased	Decreased	Same	Same
Right ventricular ejection time	Prolonged	Shortened	Constant	Constant
Pulmonic valve closure (P2)	Delayed	Earlier	Delayed	Delayed
Effect on S2	Physiological split	Split narrows / single	Wide fixed split	Wide fixed spli

1st column - normal inspiration

2nd column - normal expiration

3rd column - ASD inspiration

4th column - ASD - expiration

Wide fixed split 2nd heart sound is characteristic of

ASD

ASD seen in

• Lutenbacher syndrome

• Holt oram syndrome

• down syndrome

• Total anomalous pulmonary venous connection

Chart of s2 splitting

Bundle of His function?

Responsible for septal activation