Cardiac Cycle/Heart sounds

Question 1

S1

Answer 1

Closure of mitral and tricuspid valve

Loudest at apex

Question 2

S2

Answer 2

Closure of aortic/pulmonic

Question 3

S1 split- causes

Answer 3

RBBB

Delayed RV activaiton

Question 4

Increased/decreased S1 intensity

Answer 4

Increased: short PR interval, mitral stenosis, tachycardia

Decreased: long PR interval, mitral regurg, severe mitral stenosis, stiff LV

Question 5

What is physiological splitting?

Answer 5

Occurs with S2 upon inspiration due to delay of pulmonic valve closure bc more blood–> lungs

Question 6

What can cause widened splitting of S2?

Answer 6

RBBB, pulmonic stenosis

Question 7

Fixed splitting of S2

Answer 7

doesn’t vary with resp = atrial septal defect

Question 8

Paradoxical splitting of S2

Answer 8

Reverse pattern with resp

Due to LBBB, advanced aortic stenosis

Question 9

What are examples of extra heart sounds?

Answer 9

Ejection click

Midsystolic/late click

Opening snap

Murmurs

S3 or S4 gallop

Question 10

What causes an ejection click?

Answer 10

Abnormal valves –> abnormal valve closure or opening sounds

If heard after S1, it’s when the aortic or pulmonic valve are abnormal (i.e. bicuspid aortic) or dialted

Question 11

What causes a mid or late systolic click?

Answer 11

Due to systolic prolapse of mitral or tricuspid valve

Question 12

What causes an opening snap?

Answer 12

A thickened mitral or tricuspid valve: high pitched, best heard between apex & left sternal border

Question 13

What causes an S4 gallop?

Answer 13

End-diastolic sound (right before S1) that’s generated by L or R atrium contracting against a stiffened ventricle

Best heard at apex or LLSB– dull, low pitched sound

Usually indicates cardiac disease, may be normal in individuals over age 50 due to aging/stiffening of LV

Question 14

What causes an S3 gallop?

Answer 14

Early diastolic sound that corresponds to early ventricular filling

Dull, low pitched, best heard with bell at the apex or LLSB

Normal in children/young adults

Indicates heart failure in adults

Note that opening snap and S3 are both early diastolic sounds but opening snap is high pitched & heard btw apex & LLSB whereas S3 is low pitched at heard at apex/LLSB

Question 15

What causes a murmur?

Answer 15

Turbulent blood flow. Mechanisms:

1. Flow across a partial obstruction (stenotic valve)
2. Increased flow through normal structures (high output
   states such as anemia or pregnancy)
3. Ejection into a dilated chamber (dilated aortic root)
4. Regurgitant flow across an incompetent valve
5. Abnormal shunting of blood from one vascular
   chamber to a lower-pressure chamber (ventricular
   septal defect, patent ductus).

Question 16

What are the 3 main types of systolic murmurs:

Answer 16

Ejection type

Pansystolic=holosystolic

Late systolic

Question 17

What causes a systolic ejection murmur?

Answer 17

Aortic/pulmonic stenosis

**severity is greater if the peak of murmur is later

Question 18

What causes a pansystolic/holosystolic murmur?

Answer 18

Mitral regurg, Tricuspid regurg, VSD

Question 19

What causes late systolic murmurs?

Answer 19

Mitral valve prolapse

Question 20

What causes diastolic murmurs?

Answer 20

Early decrescendo: regurgitant flow through aortic/pulmonic valve

Mid-to-late: turbulent flow through stenotic mitral/tricuspid valve or increaed flow accross a normal valve
*if it’s stenosis, preceded by opening snap

Prolonged mid-to-late: severe mitral or tricuspid stenosis

Continuous: patent ductus arteriosus

To-and-fro: aortic/pulmonic stenosis & regurgitaiton

Question 21

Locations of murmurs

Answer 21

Question 22

Which heart sounds do you hear for the valvular diseases?

Answer 22

Aortic stenosis: S4, Harsh systolic ejection murmur, paradoxical splitting (Also: delayed carotid, reduced A2)

Aortic regurg: wide pulse pressure, blowing decrescendo diastolic murmur LLSB, low frequency diastolic rumble=Austin flint, displaced hyperdynamic LV impulse

Mitral stenosis: Increased S1, opening snap in early diastole, diastolic rumble with presystolic accentuation =murmur , signs of pulm htn (RV heave, increased P2)

Mitral regurg: holosystolic murmur at apex that worsens with fist clench, S3