Heart Sounds and Auscultation

• Auscultation involves listening at the aortic and pulmonic areas (bases), as well as the tricuspid and mitral areas (apex).

Heart Sounds

• S1 occurs due to the closure of the atrioventricular valves, specifically the mitral and tricuspid valves.
• S2 represents the closing of the semilunar valves, which include the aortic and pulmonic valves, marking the end of systole.
• Right-sided cardiac events typically occur slightly after left-sided events.

Split S1

• A split S1 is caused by a delay in the closure of the tricuspid valve.
• Potential causes are Right Bundle Branch Block (RBBB) and myxoma.
• Differentiating between S4 and a split S1 can be challenging and requires clinical correlation. An S4 is typically heard best with the bell of a stethoscope.

Physiologic Splitting of S2

• During normal physiologic splitting of S2, A2 precedes P2.
• Splitting increases with inspiration and decreases with expiration.
• Inspiration creates negative intrathoracic pressure, increasing pulmonary capacitance, increasing right ventricular filling volume, and decreasing the volume returned to the left ventricle.
• Splitting is most prominent at the peak of inspiration.
• This splitting may not be apparent in elderly patients.

Fixed Splitting of S2

• Fixed splitting of S2 is unaffected by respiration.
• It happens with delayed closure of the Pulmonary Valve due to Right Ventricular volume overload.
• Large Atrial Septal Defect, Ventricular Septal Defect with L -> R shunting, and Right Ventricular failure can cause fixed splitting.

Paradoxical Splitting of S2

• Paradoxical splitting of S2 is the reverse of normal physiology; splitting occurs during expiration and becomes singular during inspiration.
• It occurs because of delayed conduction down the left bundle.
• LBBB, pre-excitation of the right ventricle, right ventricular pacing, premature RV beats and aortic stenosis can cause paradoxical splitting.
• Paradoxical split S2 occurs with LBBB or Aortic Stenosis, delayed A2 results in reverse split: expiration split, inspiration normal.

S3 Heart Sound

• S3 results from rapid ventricular filling in early diastole.
• It is a low-pitched sound, best heard with the bell of a stethoscope at the apex while the patient is in the left lateral decubitus position (LLDP).
• It occurs immediately after S2.
• The rhythm of S1, S2, S3 is described as "Slosh-ing IN".
• S3 occurs early after S2.
• It is a normal finding in children and young adults.
• It's considered pathologic after age 40, potentially indicating LV failure (decreased ejection fraction, S3 = CHF) or diastolic volume overload from anemia, thyrotoxicosis, VSD, or MR.
• It is heard in the left lateral position.

S4 Heart Sound

• S4 results from atrial contraction against a non-compliant, stiff ventricle.
• It is low-pitched and best heard with the bell of the stethoscope at the apex.
• S4 occurs in diastole (before S1).
• It occurs late in diastole, just before S1.
• S4 is always abnormal.
• It is heard in the left lateral position.
• The sound pattern of S4, S1, S2 is characterized as "A STIFF wall”.
• Atrial fibrillation patients never have S4 sounds.
• It can be caused by HTN, Aortic Valve disease, HOCM, CAD, MR, VSD, and Amyloid Heart Disease.
• S4 is due to atrial kick into a stiff ventricle, indicating LVH and is common in Hypertension and diastolic dysfunction.

Heart Murmurs

• A heart murmur might be a normal or abnormal sound that occurs because of turbulent blood flow.
• Key characteristics include timing, location, intensity, frequency, pattern, and radiation.
• Timing refers to whether the murmur occurs during systole, diastole, or continuously.

Murmur Location

• Murmurs are best heard at specific locations:
  • RUSB (Right Upper Sternal Border).
  • LUSB (Left Upper Sternal Border).
  • LLSB (Left Lower Sternal Border).
  • Apex.

Murmur Frequency

• High-frequency murmurs are associated with:
  • Mitral Regurgitation (MR).
  • Tricuspid Regurgitation (TR).
  • Aortic Regurgitation (AR).
  • Aortic Stenosis (AS).
• Low Frequency murmurs are associated with:
  • Mitral Stenosis (MS).
  • Tricuspid Stenosis (TS).

Murmur Grades

• 1/6: Very faint, only heard with optimal conditions; no thrill.
• 2/6: Loud enough to be obvious; no thrill.
• 3/6: Louder than grade 2; no thrill.
• 4/6: Louder than grade 3; yes, thrill.
• 5/6: Heard with the stethoscope partially off the chest; yes, thrill.
• 6/6: Heard with the stethoscope completely off the chest; yes, thrill.

Murmur Pattern

• Crescendo: Intensity increases, getting louder.
• Decrescendo: Intensity decreases, getting softer.
• Square or Plateau: The intensity remains the same.
• Radiation describes where the murmur transmits, often following anatomic landmarks such as the axilla or carotid arteries.

Diastolic Murmurs

• Only Aortic Regurgitation, Mitral Stenosis, Pulmonic Insufficiency, and Tricuspid Stenosis are diastolic murmurs.

Early Diastolic Murmurs

• Aortic insufficiency (Austin Flint) can cause early Diastolic Murmurs.
• Pulmonic insufficiency (Graham-Steell) can cause early Diastolic Murmurs and is secondary to pulmonary HTN, high-pitched, and best heard at the ULSB.

Mid-Diastolic Murmurs

• Mitral and Tricuspid Stenosis cause mid-diastolic murmurs
• Mitral Stenosis: shorter S2-OS interval = more severe Mitral Stenosis

Opening Snap (OS)

• Opening snap (OS) is a brief, high-pitched early diastolic sound followed by a diastolic murmur.
• It follows S2 by 0.06 to 0.12 seconds.
• It is typically associated with mitral stenosis but can also occur in tricuspid stenosis. -The severity of mitral stenosis is related to the OS-S2 interval; the shorter the interval, the more severe the stenosis.

Systolic Murmurs

• Systolic murmurs can be innocent, physiologic, or indicative of underlying valvular or structural heart issues.
• Systolic murmurs are the following:
  • Aortic Stenosis (AS).
  • Mitral Regurgitation (MR).
  • Pulmonic Stenosis (PS).
  • Tricuspid Regurgitation (TR).
  • Ventricular Septal Defect (VSD).

Innocent Systolic Murmurs

• Innocent systolic murmurs are common and not associated with cardiovascular abnormalities.
• They are systolic in timing, peaking early and are usually short and brief.
• These murmurs are typically grade I or II in intensity.

Physiologic Murmurs

• Physiologic murmurs are not innocent and are associated with high flow states.
• Pregnancy, anemia, fever, thyrotoxicosis, and exercise can cause physiologic murmurs.

Prosthetic Heart Valves

• Porcine or bovine valves produce sounds similar to native valves but nearly always have an associated murmur.
• Mechanical valves produce crisp, high-pitched sounds from valve opening and closing. Aortic valve prostheses often have an ejection-type murmur. Mechanical valves have a crisp click + systolic ejection murmur due to non-pathologic flow turbulence.

Systolic Ejection Murmurs

• Systolic Ejection Murmurs can be innocent and physiologic.
• Aortic Stenosis (AS) and Pulmonic Stenosis (PS) can cause Systolic Ejection Murmurs.

Pansystolic Murmurs

• Mitral Regurgitation (MR), Tricuspid Regurgitation (TR), and Ventricular Septal Defect (VSD) can cause Pansystolic Murmurs

Late Systolic Murmurs

• A late systolic murmur may be preceded by a mid-systolic click.
• Mitral valve prolapse (MVP) can cause Late Systolic Murmurs.
• MVP = click + late systolic murmur, which is earlier/louder with decreased preload (Valsalva/standing), delayed/softer with increased preload (squatting)

Clicks

• Midsystolic Clicks are typically heard best at the apex.
• They are due to Mitral valve prolapse (MVP) and followed by a late systolic murmur.
• Mid or late systolic clicks are often associated with MR, Papillary muscle dysfunction, and Acute ischemic episode or angina.

Systolic Flow Murmur & Fixed Split S2:

• In Atrial Septal Defect, the systolic flow murmur is caused by increased flow along the pulmonic valve. The ASD = fixed split S2 + systolic flow murmur over the pulmonic area
• L-> R shunting resulting in a delay in pulmonic closure that produces a low systolic murmur.
• Fixed splitting of S2 is due to a delay in pulmonary valve closure (due to increased RV volume overload).

Harsh Systolic Murmur

• Hypertrophic Cardiomyopathy can cause a harsh systolic murmur.
• HOCM murmur = LLSB, no carotid radiation, increases with Valsalva (decreased preload), Aortic Stenosis = RUSB + carotid radiation
• HOCM = harsh systolic murmur, increases with Valsalva, decreases with squatting → due to LVOT obstruction from septal hypertrophy
• Murmur increases with squatting and increases with handgrip maneuvers.

Continuous Murmur

• PDA causes a loud harsh systolic-diastolic "machinery" murmur at the upper left sternal border. PDA = continuous machinery murmur, increased pulse pressure due to systemic to pulmonary runoff
• The PDA murmur is usually unaltered by postural changes.

Pericardial Friction Rub

• Pericardial friction rub is caused by inflammation of the pericardial sac that becomes roughened.
• It is a scratchy, rough, gritty sound.
• It may have presystolic, systolic, and early diastolic components, but all three need not always be present.
• When all three components are present, the sound is described as machinelike and might obscure heart sounds.
• It is best heard with the patient upright and leaning forward. Pericardial rub = scratchy, rough sound, often triphasic, best heard with patient leaning forward
• It may be accentuated during inspiration.

Inspiration

• Inspiration increases venous return.
• Right-Sided Heart Murmurs increase during inspiration. Right-sided murmurs increase with inspiration; Tricuspid Regurgitation = holosystolic at LLSB, no axilla radiation
• Right-sided heart sounds increase with inspiration.
• Physiologic splitting of S2 is more prominent during inspiration.
• Tricuspid stenosis = low-pitched late diastolic, increases with inspiration, OS present (like Mitral Stenosis) but right-sided

Squatting or Lifting Legs in Supination

• These actions increase venous return (preload) and systemic vascular resistance (afterload), causing a rise in arterial pressure.
• The intensity increases in Mitral Regurgitation, Aortic Stenosis, and Aortic Insufficiency.
• Hypertrophic cardiomyopathy murmur decreases due to increased left ventricular volume and reduces effective orifice size.
• The onset of the click and late systolic murmur in Mitral Valve Prolapse is delayed.
• HCM gets softer with squatting, and louder with Valsalva/standing (decreases in LV size resulting in an increase in the murmur)
• Murmur decreases with squatting.

Standing or Valsalva

• Decreases venous return, right and left ventricular diastolic volumes, and stroke volumes.
• Hypertrophic Cardiomyopathy murmur increases due to decrease in left ventricular outflow size.
• Aortic Stenosis and Mitral Regurgitation murmurs decrease.
• MVP click earlier/louder with standing/decreased preload; click delays with squatting

Isometric Exercise (Handgrip)

• It increases arterial pressure and afterload.
• It is most useful in differentiating between the ejection systolic murmur of aortic stenosis and the regurgitant murmur of mitral insufficiency.
• Mitral Regurgitation murmurs increase. Mitral Regurgitation = pansystolic at the apex, radiates to the axilla, increases with handgrip, no change with inspiration
• Aortic Stenosis murmurs decrease (decreased transvalvular pressure gradient) and HOCM.

Amyl Nitrite

• It is an arteriolar dilator.
• It causes marked vasodilation (decreased Systemic vascular resistance) and also a decrease in arterial pressure.
• Mitral regurgitation decreases.
• The ejection systolic murmur of aortic and pulmonary stenosis, hypertrophic cardiomyopathy, and innocent systolic flow murmurs are all increased.
• Ventricular Septal Defect = harsh holosystolic murmur at the LLSB, thrill, increases with handgrip, decreases with amyl nitrate.
• Aortic Stenosis → harsh diamond-shaped murmur, RUSB, carotid radiation, increases with squatting, decreases with handgrip, delayed upstroke
• Aortic Regurgitation → high-pitched decrescendo murmur increases with handgrip, and wide pulse pressure

Aortic Stenosis

• Aortic Stenosis murmur is heard best at the right sternal border (RUSB).
• It radiates to the carotid arteries.
• It is associated with a decreased upstroke.

Mitral Regurgitation

• Mitral Regurgitation murmur is heard best at the apex.

Ventricular Septal Defect

• Ventricular Septal Defect murmur is heard best at the left sternal border.

Aortic Regurgitation

• Aortic Regurgitation murmur, leaning forward in full exhalation increases the severity of the murmur.
• The aortic regurgitation murmur is associated with a wide pulse pressure.

Mitral Stenosis

• Mitral Stenosis is associated with an opening snap from the thickened mitral valve, best heard in the left lateral position at the apex.

Patent Ductus Arteriosus (PDA)

• PDA is a machinery-like murmur due to blood flow from the aorta to the pulmonary artery.