Chapter V Thorax

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Chapter V Thorax

• D. Heart and blood vessels
• Heart Part II
• by Dr. Zhuo-ren Lu

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IV. Auscultation

• A. A routine procedure of auscultation includes
  heart rate, rhythm, cardiac sound, extra heart
  sound, cardiac murmur and pericardial friction
  sound.
• 1. Auscultatory valve area
• (1) The mitral valve area is in the 5th left
  intercostal space, 1 or 2 cm medial to the
  midclavicular line or the apical impulse area
  particularly in pathological cases.
• (2) The pulmonary valve area is in the second
  left intercostal space just lateral to the
  sternum.

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• (3) The aortic area is located in the second
  right intercostal space just lateral to the
  sternum.
• (4) The second aortic area is in the 3rd or 4th
  left intercostal space lateral to the sternum.
• (5) The tricuspid valve area is located at the
  left or right side of the junction of the xiphoid
  process and the sternum.
•  The routine procedure of auscultation is
  recommended as counterclockwise direction apex ?
  pulmonary valve area ? aortic valve area ? second
  aortic valve area ? tricuspid valve area.

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• 2. Heart rate (HR) and rhythm
•   The heart rate normally varies with age, sex
  and physical activity. In adults, it usually
  varies from 60 to 100 beats per minutes. The rate
  is increased (tachycardia) in severe anemia, high
  fever, hyperthyroidism, heart failure and various
  types of arrhythmia.
• The HR above 160 beats/min indicates that the
  supraventricular tachycardia.
• The heart rate may be decreased (bradycardia)
  in increased intracranial pressure, obstructive
  jaundice, syncopy, complete heart block, and most
  cases of sick sinus syndrome.

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• l There may be a pulse deficit (HR ? pulse rate)
  in atrial fibrillation(Af), which constitutes a
  grossly irregular rhythm and extremely variable
  in heart sound.
• Normally, the rhythm of the heart beat is
  regular or slight irregular during respiration
  with no clinical importance, and any deviation
  from this regularity is termed arrhythmia.
• The most common cause of the arrhythmia is
  premature contraction (extrasystole). It may
  occur as the result of excessive smoking or
  alcoholic intake, and also in some organic heart
  diseases.
•   In bigeminal beats it is coupled or occurs
  in pair, with the second beat usually being
  weaker. In trigeminal beats, there is a pause
  after every third beat.

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3. Heart sounds

• (1) The first heart sound (S1 )
• l    It is mainly produced by closure of both the
  mitral and tricuspid valves. The mitral valve
  closure precedes slightly that of the tricuspid
  valve.
• l    S1 is synchronous with the apical impulse
  and corresponds with the onset of ventricular
  systole.

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• (2) The second heart sound (S2 )
• l    It is produced by closure of both the aortic
  and pulmonary valves. Normally, aortic valve
  closure precedes pulmonary valve does.
• l    Normally, P2 ? A2 in children and young
  persons, P2 ? A2 in old persons, and P2 ? A2 in
  mid-age persons.

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• The differentiation between S1 and S2
• There is a longer pause between S2 and the
  subsequent S1 (diastole) than between S1 and S2
  (systole).
• S2 is usually clearly audible in the pulmonary
  valve area.
• S2 is higher in frequency and shorter in duration
  than S1.
• It may identify S1 by synchronous palpation at
  the apex or over the carotid artery.

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• (3) The third heart sound (S3) (S3)
• Being low in both frequency and intensity, it
  is best heard with the bell of the stethoscope.
• It occurs during the phase of early diastolic
  filling after S2. This sound is heard in most
  children and some adults.
• (4) The fourth heart sound (S4)
• Like the third sound, S4 is also low in
  frequency and intensity, and is best heard at the
  apex. The sound occurs late in diastole and is
  related to atrial contraction. It is rarely heard
  under normal condition.

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A. Changes of intensity

• (1) All heart sounds
• In some patients with pulmonary emphysema or
  a very muscular chest wall, all heart sounds may
  be distant.
• (2) S1
• The principal factor responsible for the
  intensity of is the position of the
  atrioventricular valve at the onset of
  ventricular contraction.

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• l  A loud S1 may be heard in mitral stenosis
  because less filling from left atrium to left
  ventricle and then the mitral valve in a lower
  position at the moment of ventricular
  contraction.
• l Tachycardia, anemia, fever, exercise, and
  hyperthyroidism may be associated with an
  intensity of S1.
• l A lower S1 may be caused by the illness of
  myocardium.

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• (3) S2
• l   S2 becomes louder with hypertension or
  pulmonary artery hypertension.
• l  A decrease in intensity of S2 over the aortic
  and/or pulmonary valve area may be caused by the
  damaged integrity and activity of the related
  semilunar valve.

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B. Splitting of heart sounds

• (1) A widely splitting of S1 at the apex suggests
  commonly the possibility of right boundle branch
  block because the second component of S1 delays.
• (2) Splitting of S2 is of great practical
  importance. It is the results of the marked
  asynchrony between the aortic valve and pulmonary
  valve closure. Because of the normal increase in
  venous return to the right side of the heart on
  inspiration, the right ventricle requires a
  slight longer period to empty itself.

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• Normal splitting in pulmonary valve stenosis and
  pulmonary artery hypertension and CRBBB, the
  splitting of S2 is clearly audible with
  inspiration.
• Fixed splitting in ASD, there is a wide fixed
  split of S2 over the pulmonary valve area with
  little or no change in the degree of splitting
  during either phase of respiration.
• Paradoxical splitting in CLBBB, the order of
  valve closure may be reversed. On expiration,
  pulmonary closure occurs first and is followed by
  aortic valve closure. During inspiration the
  pulmonary valve closure is normal delayed, with
  increased filling on the right side of the heart,
  and the two components then move closer together
  on inspiration.

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C. Extra heart sounds

• Diastolic extra heart sounds gallop rhythm
  (ventricular gallop, atrial gallop, summation
  gallop), opening snap, pericardial knock
• Systolic extra heart sounds systolic ejection
  sounds and ejection clicks
• (1) Gallop rhythm The term refers to that
  condition in which three and occasionally four
  heart sounds are spaced to audibly resemble the
  canter of a horse.

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• ?The protodiastolic (ventricular gallop) is a
  brief low-pitched sound, usually heard near the
  end of the first third of diastole.
• It is the pathologic counterpart of the third
  heart sound and occurs at the time of rapid
  diastolic ventricular filling. The ventricular
  gallop sound is produced by an overdistension of
  the ventricle in the rapid filling phase of
  diastole, associated with an increase in
  ventricular diastolic volume and pressure.
• Ventricular gallop is usually heard at the
  apex in ventricular failure from any cause.

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• Presystolic (atrial gallop)
• l It is associated with systolic overloading of
  ventricles where the ventricular diastolic
  pressure is elevated, namely, in systemic or
  pulmonary hypertension and in aortic or pulmonary
  stenosis.
• l  The atrial gallop may also occur wherever the
  distensibility of the ventricle is impaired, such
  as MI, hypertension, and myocardiopathy.
• l  It may even precede the signs of left
  ventricular hypertrophy.
• The atrial gallop sound is low-pitched, of
  short duration, and is best heard when the bell
  of the stethoscope is applied lightly to the
  chest wall.

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• Quadruple rhythm
• When both the ventricular and atrial gallop
  sounds are present, this results in a quadruple
  rhythm.
• Summation gallop
• If both the ventricular and atrial gallop sounds
  are present and the heart rate increases, the
  diastolic interval shortens and the extra sounds
  come closer together. They may actually fuse,
  resulting in a summation gallop.

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(2) Opening snap

• The opening snap occurs soon after S2 and is
  produced by opening of the atrioventricular
  valves.
• l  In mitral stenosis, the valve forms a
  restrictive diaphragm, which bulges into the left
  atrium during systole and then springs into the
  left ventricle when atrial pressure suddenly
  exceeds ventricular diastolic pressure.
• l  This sound is brief in duration and higher in
  pitch than other gallop sounds.
• l  It is heard best in the left 3rd and 4th
  parasternal areas with the patient in left
  lateral position.

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• (3) Pericardial knock
• In the presence of constrictive pericarditis,
  at times an extra sound is heard in diastole
  occurring shortly after S2.
• It occurs earlier in diastole than the
  ventricular gallop does. Pericardial knock is
  higher in frequency and transmitted widely than
  opening snap.
• It is heard best in the apex or the left lower
  parasternal area.

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(4) Systolic ejection sounds and ejection clicks

• Pulmonary ejection clicks may occur in
  stenosis of the pulmonary valve, in pulmonary
  hypertension, and in that situation where the
  pulmonary artery is dilated. They are best heard
  over the pulmonary auscultatory valve area.
• ? Aortic ejection clicks occur in stenosis of the
  aortic valve, aortic regurgitation, aneurysm of
  the ascending aorta, and hypertension with
  dilatation of the aorta. They are heard over the
  base of the heart as well as at the apex.

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• Some middle and late systolic clicks occur just
  prior to or during a late systolic murmur. The
  systolic click is probably related to the
  prolapsed mitral valve with longer chordae or
  exuberant leaflets. Following the termination of
  the prolapse, the late murmur is a reflection of
  late systolic mitral regurgitation. It is
  referred to as mitral valve prolapse syndrome
  (middle and late systolic clicks - late systolic
  mitral regurgitation).

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4. Cardiac murmurs

• Cardiac murmurs are abnormal sounds produced
  by vibrations within the heart itself or in the
  walls of the large arteries. Murmurs are
  definitely longer in duration than heart sound,
  and are clearly audible with different qualities.

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A. Mechanism of production

• 1. Increasing the rate or velocity of blood flow
• 2. Decrease in the diameter of a heart valve or a
  constriction in one of the major arteries
• 3. Valve insufficiency
• 4. The abnormal communication between the right
  and left sides of chambers
• 5. By inserting a taut membrane (vegetation,
  ruptured chordae)
• 6. By a sudden increase in the diameter of a
  major vessel (aneurysm).

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B. Characterization of murmurs

• (1) Location
• The described location of a murmur is the site
  of precordium where it is audible most
  significantly. Murmurs of valvular origin are
  usually best heard over their respective
  auscultatory valve areas.

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(2) Timing

• Systole and diastole may be divided into
  three parts early, middle, and late. Murmur may
  occur one part of systole or diastole, but at
  times may persist throughout systole.
• Certain systolic murmurs are produced by
  insufficiency of the mitral and tricuspid valves
  or by stenosis of the aortic and pulmonary
  valves.
• Most diastolic murmurs are the results of
  stenosis of the mitral and tricuspid valves or
  insufficiency of aortic and pulmonary valves.
• The most common lesions encountered are
  mitral stenosis, mitral and aortic insufficiency.

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(3) Quality

• On occasion the quality of cardiac murmurs may
  be of assistance in arriving at a more accurate
  diagnosis.
• l    A blowing systolic murmur is often produced
  in mitral or tricuspid insufficiency and atrial
  or ventricular septal defect.
• l    The mid- and late diastolic murmurs caused
  by mitral stenosis increase in intensity and
  assume a rumbling quality.
• l    High-pitched blowing murmurs may resemble
  the sound of a whistle and at times are musical
  in character (vegetation or ruptured chordae).

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(4) Intensity

• l    A grade I murmur is barely audible.
• l    A grade II murmur is usually readily heard
  and slight louder than grade I.
• l    Grade III and IV murmurs are quite loud.
• l    Grade IV is often accompanied by a thrill.
• l  Grade V is even more pronounced, and also
  accompanied by a thrill.
• l    A grade VI murmur is so loud that even it
  may be heard with the stethoscope just removed
  from the chest wall.

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• l   Grade I and II are frequently encountered in
  persons without organic heart disease, whereas
  those of grade III intensity or louder seldom
  occur in a normal heart.
• l   In clinic, diastolic murmurs are not graded
  because most of them occur in organic heart
  diseases.

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(5) Transmission

• Some murmurs are transmitted with or in the
  direction of the bloodstream by which they are
  produced.
• l   The murmur of aortic regurgitation may be
  heard distinctly down along the left border of
  the sternum and over the apex.
• l  The murmur caused by aortic stenosis may be
  audible over the carotid arteries.
• L The murmur of mitral regurgitation may
  transmit with the direction to left axilla.

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C. Classification of murmurs

• (1) Systolic murmurs
• Ejection murmurs is short in duration. They
  begin after S1, attain a peak in early or middle
  systole, and terminate before S2.
• Examples of systolic ejection murmurs are
  those in aortic stenosis and pulmonary stenosis,
  including the vast majority of so-called
  functional murmurs.

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• Pansystolic murmurs It is of longer duration
  than the ejection murmur and usually obscures S1
  and S2.
• l    Mitral pansystolic murmurs are high-pitched,
  blowing in character, and frequently radiate
  toward the left axilla. Pansystolic murmurs are
  usually associated with mitral regurgitation,
  tricuspid regurgitation and VSD.
• l    Murmurs that originate on the right side of
  the heart frequently increase in intensity during
  the course of inspiration. This fact may assist
  in differentiating tricuspid from mitral
  regurgitation and also in distinquishing between
  pulmonary and aortic ejection murmurs.

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• Functional systolic murmur is commonly heard in
  children and young adults without any structural
  abnormality or recognizable heart disease.
• It is characteristically soft, blowing or
  ejection in quality, early, short, limited area,
  slight in intense (grade I or II), and variable.
• It is usually heard best at the pulmonary
  valve area and apex. Functional murmur varies
  with position and respiration.

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(2) Diastolic murmurs

• ?Regurgitant diastolic murmur is early in onset,
  beginning immediately after S2, is longer in
  duration, and is pandiastolic in nature.
• l    The murmur of aortic regurgitation is
  high-pitched, sighing or splashing in character,
  and transmitted along the left lower sternal
  border or the direction to the apex.
• l    Regurgitant diastolic murmur also may occur
  in pulmonary regurgitation.

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• Ventricular filling murmurs
• are low-pitched diastolic murmurs. In true mitral
  stenosis there is a definite delay in emptying of
  the left atrium.

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Austin Flint murmur

• ?Relative stenosis of the mitral or tricuspid
  valve may occur in mitral regurgitation, aortic
  regurgitation, and in some cases of congenital
  heart disease with left-to-right shunt. This
  murmur is less intense and shorter in duration
  than its organic counterpart. The non-obstructed
  mitral valve with higher position becomes
  relatively stenotic with respect to accommodating
  this large volume of blood.

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Graham Steell murmur

• ?A soft diastolic murmur may be heard over the
  pulmonary auscultatory valve area. It is caused
  by the relative regurgitation of the pulmonary
  valve owing to the dilatation of pulmonary artery
  when mitral stenosis exists.

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(3) Continuous murmurs

• The prototype of a continuous murmur is the
  Gibson murmur of patent ductus arteriousus. It is
  heard maximally under the left clavicle.

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5. Pericardial friction rub

• l  This to-and-fro rubbing be heard over the
  entire precordial region or a very small area.
• l    It may be heard in both phases of the
  cardiac cycle. Pericardial friction rub is
  unaffected by respiration and is thus
  differentiated from a pleural friction rub.
• l  It is also increased as pressing the
  stethoscope firmly against the patients chest
  wall.
• l    A rub may be readily heard at one moment and
  be absent several minutes later.
• l    The intensity of the rub is usually
  increased when the subject is sitting upright and
  leaning forward.