HEART SOUNDS

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CARDIOVASCULAR SYSTEM CARDIAC CYCLEHEART SOUNDS
LECTURE 4 DR. ZAHOOR ALI SHAIKH
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HEART SOUNDS
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• There are four heart sounds SI, S2, S3 S4.
• Two heart sound are audible with stethoscope S1
  S2 (Lub - Dub).
• S3 S4 are not audible with stethoscope Under
  normal conditions because they are low frequency
  sounds.
• Ventricular Systole is between First and second
  Heart sound.
• Ventricular diastole is between Second and First
  heart sounds.

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First heart sound (S1)

• It is produced due to the closure of
  Atrioventricular valves (Mitral Tricuspid)
• It occurs at the beginning of the systole and
  sounds like LUB
• Frequency50-60 Hz
• Time 0.15 sec

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Second heart sound (S2)

• It is produced due to the closure of Semilunar
  valves (Aortic Pulmonary)
• It occurs at the end of the systole and sounds
  like DUB
• Frequency80-90 Hz High pitch
• Time 0.12 sec
• It is short and sharp

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HEART SOUNDS

• Important
• Sounds are caused by vibrations set within the
  wall of the ventricles and major arteries during
  valve closure .
• Opening of the valve does not cause sound.

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Third heart sound (S3)

• It occurs at the beginning of middle third of
  Diastole
• Cause of third heart sound Rush of blood from
  Atria to Ventricle during rapid filling phase of
  Cardiac Cycle. It causes vibration in the blood
• Frequency20-30 Htz
• Time 0.1 sec

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Fourth heart sound (S4)or Atrial Sound

• It occurs at the last one third of Diastole
• (just before S1)
• Cause of Fourth heart sound Due to Atrial
  contraction which causes rapid flow of blood from
  Atria to Ventricle and vibration in the blood.
• Frequency lt 20 Htz
• Note
• Third and Fourth heart sound are low pitched
  sounds therefore not audible normally with
  stethoscope
• S3 may be heard in children and young adults but
  usually pathological in old age

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EVENTS
0.7 Sec. 0.1 sec.
AD AS
VS VD
0.3Sec. 0.5 sec.
1 st Heart Sound
2 nd Heart Sound
3 rd Heart Sound
4 th Heart Sound
HEART SOUNDS
AS Atrial Systole AD Atrial Diastole VS Ventricular systole VD Ventricular diastole
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Aortic Area 2nd right Intercostal space at the
right sternal border Pulmonary Area 2nd left
Intercostal space at the left sternal
border Mitral Area 5th left Intercostal space
1cm inside mid clavicular line Apex beat
area Tricuspid Area Left side of lower
sternum
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Heart Murmurs

• Murmurs are abnormal sounds produced due to
  abnormal flow of blood turbulent blood flow
  through abnormal heart valves e.g.. stenosis or
  incompetence.
• Stenosis means narrow or stiff, valve that does
  not open completely.
• Incompetent means valve which does not close
  properly and remains open.

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Heat Murmurs

• When blood is forced through stenotic valve, it
  produces an abnormal whistling sound.
• When blood flows backward through incompetent
  valve, it produces swishing or gurgling murmur
  sound.
• Most common cause of stenosis and incompetent
  valve is Rheumatic fever, an auto immune disease
  triggered by Streptococcus bacterial infection.

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Heat Murmurs

• Systolic murmur are produced during the systole
  of the ventricle, between 1st and 2nd heart sound
  (Lub Murmer Dup).
• Diastolic murmur are produced during the diastole
  of the ventricle, between 2nd and 1st heart sound
  (Lub Dup Murmer Lub).
• During aortic stenosis and mitral incompetence
  systolic murmur.
• Aortic incompetence and Mitral Stenosis
  diastolic murmur.

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• We will discuss
• PRESSURE VOLUME LOOP
• 2. EVENTS OF CARDIAC CYCLE

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Relationship between Lt. ventricular volume
pressure changes
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• Events of cardiac cycle for Lt. ventricular
  function showing changes in Lt. atrial pressure,
  Lt. ventricular pressure, aortic pressure,
  ventricular volume, ECG phonocardiogram

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WHAT YOU SHOULD KNOW FROM THIS LECTURE?

• Functions of A-V vales Semilunar valves.
• Functions of papillary muscles.
• There are four heart sounds
• S1, S2, S3, S4.
• Audible with stethoscope are only S1(Lub)
  S2(Dub / Dup)

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• Places to be auscultated on the chest for heart
  sounds i.e. Aortic, pulmonary, Mitral tricuspid
  area.
• Murmurs (abnormal heart sounds).
• Pressure Volume Low
• Cardiac Cycle Diagram Phases, Pressure, Volume,
  and Heart Sounds

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THANK YOU