Cardiac cycle

Question 1

WIGGERS DIAGRAM

Answer 1

KNOW

Question 2

Ventricular diastole

Answer 2

Ventricular filling
LAP > LVP
LA also contracts, adds a little bit of volume

Question 3

Isovolumetric contraction

Answer 3

LVP rises above LAP (close mitral - S1)
Continues until LVP > aortic P
Also causes a small increase in LAP (bulging mitral valve)

Question 4

Ejection phase

Answer 4

LVP>AP
ventricles contracting at the beginning
ventricle starts to relax, LVP and AP start to drop, LVP drops faster
Once AP > LVP, aortic closes (S2)
Steady increase in LAP due to filling

Question 5

Isovolumetric relaxation

Answer 5

when LVP drops below LAP, mitral reopens

Question 6

S1

Answer 6

closure of AV valves
early systole
normally heard as 1 sound
high frequency
vibrations of the valves & wall of the heart
best heard at the apex

Question 7

S2

Answer 7

closure of semi-lunar valves
high frequency
pulmonary closure (P2): best at 2-3 left intercostal space sternal border
aortic closure (P2): best at right side
expiration: one sound
inspiration: physiological splitting (MTAP)

Question 8

S3

Answer 8

tending of chordae tendinae during rapid filling and expansion of the ventricle
-normal in children & young adults
-disease state in older adults. ex. volume overload, increased transvalvular flow during advanced mitral or tricuspid regurgitation
“ventricular gallop”

Question 9

S4

Answer 9

atria vigorously contracting against a stiffened ventricle
-late in ventricular diastole
-disease in ventricular compliance from hypertrophy/ischemia
“atrial gallop”

Question 10

Physiologic S2 splitting

Answer 10

inspiration –> increase in capacity of pulmonary vessels

• delayed P2 due to delay in pulmonic valve closure
• decrease venous return to LA –> reduced SV –> earlier closing of aortic valve (earlier A2)

Question 11

Widened splitting S2

Answer 11

increase in splitting; can be heard during expiration, even wider during inspiraton
-usually delayed closure of pulmonic valve due to RBBB and pulmonic stenosis

Question 12

Fixed splitting S2

Answer 12

Most common cause: ASD; chronic volume overload of the R side results in high capacitance, low resistance pulmonary system –> delays back pressure, P2 occurs later than normal
Inspiration does not significantly change already raised pulmonary capacitance
Increased filling of RA is balanced by decrease in L to R transatrial shunt, eliminating respiratory variations

Question 13

Paradoxical/reversed splitting S2

Answer 13

heard during expiration, not inspiration

• abnormal delay in A2
• P2 delayed during inspiration and A2 is earlier, superimposed during inspiration
• most common cause: LBBB
• also occurs when ventricular ejection is greatly prolonged (aortic stenosis)

Question 14

5 mechanisms of heart murmurs

Answer 14

1. normal flow across a partial obstruction
2. increased flow through normal structures
3. ejection into a dilated chamber
4. regurgitant flow across an incompetent valve
5. abnormal shunting

Question 15

Description of murmurs

Answer 15

1. Timing: diastole, systole, continuous
2. Intensity:
   Systolic Murmurs:
   1/6 barely audible
   2/6 faint but immediately audible
   3/6 easily heard
   4/6 easily heard, palpable thrill
   5/6 very loud, heard with stethoscope lightly placed on chest
   6/6 audible without stethoscope directly on chest wall

Diastolic Murmurs:
1/4 barely audible
2/4 faint but immediately audible
3/4 easily heard
4/4 very loud

Pitch: frequency (high = large pressure gradient)

Shape: crescendo-decrescendo (ejection), decrescendo, uniform

Location
Radiation
Response to maneuvers: