lecture on heart sounds by dr. roomi

7/30/2019 Lecture on Heart Sounds by Dr. Roomi

http://slidepdf.com/reader/full/lecture-on-heart-sounds-by-dr-roomi 1/15

Heart Sounds

• During each cardiac cycle, 4 heartsounds are produced.

• These can be recorded inphonocardiogram.

• By auscultation we can hear/

auscultate, 1st & 2nd heart sounds &sometimes 3rd as well.

• But 4th is Atrial heart sound, whichis never auscultated normally.

• 1st & 2nd heart sounds are called asCLASSICAL HEART SOUNDS (as theyare usually auscultated in normalsubjects).



4 Auscultatory areas

• Pulmonary Area: Left 2nd intercostal space, close tosternal border.

• Aortic Area: Right 2nd intercostalspace, close to sternal border.

• Mitral Area: left 5th intercostalspace in the midclavicular line, 9cm away from the sternalborder.

•

Tricuspid Area: 4th

leftintercostal space close to sternalborder.



4 basic factors affecting Heart Sounds:

• Acceleration of blood: Sudden flow.

• Deceleration: Sudden stoppage of blood flow.

•

Turbulance in the flow of blood.• Thickness of chest wall.



1st Heart Sound

Characteristics:

• Long, soft, low pitched.

(heard as LUBB)

• Frequency: 30 –

50cycles /sec.

• Duration: 0.14 sec



1st Heart Sound

CAUSES:

• Vibrations due to closure of AV valves, at the beginningof ventricular systole.

• Vibrations in ventricles &large vessels whenventricular musclecontracts.

• Vibrations when bloodstarts ejecting into largeartery.



Physiological Splitting of 1st heart sound

Mechanism:

• Tricuspid valve may

close earlier than

mitral.



Intensity of 1st heart sound

Depends on:

• Force of ventricular

systole.

• Rate of increase in

ventricular pressure,

during isovolumiccontraction phase.



2nd Heart Sound

Characteristics:

• Short, sharp, high pitched

(heard as DUBB)

• Frequency: 50 – 200 cycles /

sec.

• Duration: 0.11 sec



2nd Heart Sound:

Minor causes:

• When blood flows from

ventricle to large

arteries, there may beturbulance.



Splitting of 2nd Heart Sound:

• PHYSIOLOGICAL

• Increases or Widens duringinspiration (0.5 sec) & decreasesduring expiration (0.02 sec ordisappear).

Cause of splitting:

• During inspiration venous returnincreasesmore blood returns toright atrium right ventricle more ejection delayed closure of pulmonary valve.

• Reverse occurs in expiration.

• PATHOLOGICAL

• In bundle branch block, mainly rightbundle branch block.

• Intensity of pulmonary component of

2nd heart sound is increased inpulmonary hypertension.

• Intensity of aortic component isincreased in systemic (aortic)hypertension



3rd Heart Sound:

Cause: Vibrations produced inventricular wall during Rapid InflowPhase.

Prominent sometimes in children.

Can be made prominent by increasing

venous return:i) exercise.

ii) lying position.

• Low frequency sound.

• Duration: 0.04 sec.

• Best heard at: Apex of heart, in 5th intercostal space (mid-clavicularline).



4th Heart Sound:

• Not normally auscultated butrecorded in phonocardiogram.

• Low frequency, low intensity sound.

• Produced just before 1st heart sound.

• Also called ATRIAL HEART SOUND.

Cause:

• Vibrations of ventricular wall, due toimpact of blood pumped from theatrium into ventricle during Atrial

Systole.

Diseases:

• In CCF, 4th Heart Sound is auscultated.



MURMURS:

• These are abnormal heartsounds.

Produced when:

1. Valvular stenosis.

2. Valvular incompetence.

3. Hyperdynamic circulation: Hyperthyroidism,

severe anemia (hemicmurmurs)



MURMURS

• Systolic murmurs:

– Aortic stenosis

– Mitral regurgitation

• Diastolic murmurs:

– Aortic regurgitation

– Mitral stenosis

• Murmur throughout

cardiac cycle:

– Patent ductus arteriosus

(PDA)- its murmur is also

called as machinary murmur.

lecture on heart sounds by dr. roomi

Documents