Heart sounds

Question 1

Normally heard heart sounds

Answer 1

• S1 (lub): closure of the AV valves (tricuspid and mitral)
• S2 (dub): closure of semilunar (Ao and pulm) valves
• S2 can be split up into A2P2: A2 is closure of Ao valve and P2 is closure of pulmonary valve (Ao valve normally closes a little before pulm valve)
• There is wider splitting of A2P2 during inspiration (physiologic splitting)

Question 2

Third heart sound (S3)

Answer 2

• Early diastolic sound (right after S2), possibly due to tensing of chord tendinae as rapid filling of ventricles happens
• Normal in children and young adults
• Corresponds to volume overload or CHF in adults
• “Kentucky”

Question 3

Fourth heart sound (S4)

Answer 3

• Late diastolic sound (right before S1), caused by atrial contraction and blood hitting a noncompliant ventricle
• Usually due to ventricular hypertrophy or myocardial ischemia
• “Tennesse”

Question 4

Opening snap (OS)

Answer 4

• Sharp, high-pitched sound shortly after S2
• Associated w/ mitral or tricuspid stenosis
• Heard best btwn apex and left sternal border
• Midsystolic click: mitral prolapse

Question 5

Paradoxical splitting of S2 (LBBB)

Answer 5

• In LBBB the RV contracts slightly before the LV, so the plum valve closes before the Ao valve (P2 before A2)
• Inspiration will always delay the closure of pulm valve, so for paradoxical splitting inspiration moves the P2 sound back and more in-line w/ A2 (makes it better)

Question 6

Wide splitting of S2 (RBBB and ASD)

Answer 6

• RBBB and ASD cause the opposite of paradoxical splitting, which is a wider A2-P2 gap
• However, now inspiration does not change P2 any further

Question 7

Mechanisms of murmurs

Answer 7

• Flow across partial obstruction (AS, MS)
• Increased flow through normal structures: Ao systolic ejection murmur
• Ejection into a dilated chamber: Ao systolic murmur from Ao aneurysm
• Regurgitant flow (MR/AR)
• Abnormal shunting of blood from high-low pressure (VSD)

Question 8

Characteristics of murmurs

Answer 8

• Timing (systolic vs diastolic)
• Intensity
• Pitch
• Shape
• Location
• Radiation
• Response to maneuvers

Question 9

Grading of murmurs

Answer 9

• Systolic: out of 6 (may be physiologic)
• 1-3 subjective: based on how loud (3/6 means audible in multiple locations)
• 4: easily heard and palpable thrill
• 5: audible w/ scope at angle
• 6: audible w/ scope off chest
• Diastolic: out of 4 (always pathologic)
• Always subjective based on volume

Question 10

Characteristics of Ao stenosis murmur

Answer 10

• Systolic, high-pitched
• Crescendo-decrescendo
• Heard best in Ao area
• Radiates to carotids

Question 11

Characteristics of Ao regurg murmur

Answer 11

• Early diastolic (right after S2), high-pitched
• Decrescendo
• Best heard at left sternal border w/ pt sitting, leaning forward, exhaling

Question 12

Characteristics of mitral regurg murmur

Answer 12

• Holosystolic, high-pitched and blowing
• Uniform intensity
• Heard best at apex, radiates to left axilla

Question 13

Characteristics of mitral stenosis murmur

Answer 13

• Mid-late diastole, low-pitched
• Decrescendo w/ late diastolic intensification
• Heard best with bell at apex w/ pt in left lateral DQ position