Cardiac Cycle

Question 1

S1

Answer 1

mitral valve and tricuspid valve closure; loudest at mitral area

Question 2

S2

Answer 2

aortic and pulmonary valve closure

Question 3

what marks beginning of systole? end?

Answer 3

S1 is the beginning; S2 marks the end

• has isovolumetric contraction phase, rapid ejection and rduced ejection phase

Question 4

JVP ⇒ a wave

Answer 4

atrial contraction ⇒ is the increase in atrial pressure caused by atrial systole; occurs just before S1

Question 5

JVP ⇒ c wave

Answer 5

caused by the closed tricuspid valve bulging into the atrium due to RV contraction during systole

Question 6

JVP ⇒ v wave

Answer 6

increased R atrial filling due to filling against closed tricuspid valve

Question 7

S3 (when heard and why; when in cycle is it heard)

Answer 7

heard in early diastole during rapid ventricular filling phase; this is just after S2

Question 8

what two pop. have a normal S3?

Answer 8

children and pregnant women

Question 9

a pathologic S3 is associated with what general issue

Answer 9

increased filling pressures ⇒ common in dilated ventricles

Question 10

4 conditions specifically a pathologic S3 is heard

Answer 10

1. dilated cardiomyopathy
2. CHF
3. Mitral regurgitation
4. L → R shunts

Question 11

S4 (what causes, when in cycle is it heard)

Answer 11

due to “atrial kick” in late diastole, last push to get all blood out of ventricle; just before S1

Question 12

what general condition makes S4 louder?

Answer 12

stiff ventricles→ having to push harder to get all blood out

Question 13

4 specific conditions that can cause a pathologic S4

Answer 13

1. hypertrophic cardiomyopathy
2. Aortic stenosis
3. chronic HTN with Left vent. hypertrophy
4. post-MI → can be a sign someone has had one!

Question 14

on the pressure volume loop, what happens to the graph with ↑ afterload (like in HTN)

*what happens to SV and ESV

Answer 14

graph gets taller and skinnier; more force being used just to overcome the systemic pressure so theres not much more energy for systolic ejection when the pressures finally get high enough to open aortic valve

• ↓ SV and ↑ ESV

Question 15

what happens to the pressure volume loop with ↑ contractility? what hapens to SV, EDV and EF

Answer 15

gets taller and wider on the left side ⇒ ↑ SV and ↓ EDV; EF thus increases

• the right side of the graph is the same as baseline

Question 16

what happens to the pressure volume loop with ↑ preload? What variable changes

Answer 16

gets wider to the right, but everything else stays the same⇒ increasing width on the x-axis means ↑ SV (due to ↑ EDV, but ESV is same as baseline)

Question 17

what is normal splitting? which heart sound and which valve closes first and why? w/ expiration or inspiration?

Answer 17

on INSPIRATION, the ↓ in intrathoracic pressure allows more venous return, so the left ventricle gets more volume than the right. Thus it takes the right ventricle longer to close and during S2, the aortic valve closes first and the pulmonary second

Question 18

what is wide splitting in general? which heart sound?

Answer 18

splitting of S2, with aortic valve closing first, like normal inspiratory splitting, but occurs during expiration as well (not normal)

Question 19

what issue in general causes wide splitting? two examples?

Answer 19

anything that delays RV emptying

1. pulmonic stenosis
2. right bundle branch block

Question 20

What is fixed splitting? what condition is it due to?

Answer 20

increased RA and RV volumes such that regardless of breath, pulmonic closure is delayed and S2 is split (aortic first)⇒ seen in ASD! (L to R shunt). Split is wider than in wide splitting

Question 21

what is paradoxical splitting and when can it be heard in breathing cycle? what general condition causes it

Answer 21

normal splitting is reversed, so on expiration⇒ P2 sound is heard first. Due to conditions that delay LV emptying. On inspiration (when normal splitting should be there), the split paradoxically decreases (P2 still abnormally closing first)
* split decreases, due to the ↑ RV volume on inspiration; allows the A2 to almost catch up

Question 22

2 conditions that can cause a paradoxical split

Answer 22

1. aortic stenosis

2. left bundle branch block