Transcript HEART SOUNDS

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CARDIOVASCULAR SYSTEM
CARDIAC CYCLE
HEART 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
• Frequency:50-60 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
• Frequency:80-90 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
• Frequency:20-30 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: < 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
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usually pathological in old age
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 10
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 –
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diastolic murmur.
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We will discuss
1. 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
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