L31

Question 1

Compare L vs RV stroke volume

Answer 1

The same!!!

RV pumps same SV w/ less work b/c lower resistance in pulm vasc

Question 2

RV contraction shape/type

Answer 2

Longitudinal - contracts down

Question 3

Equation for La Place’s law

Answer 3

wall tension = (P x r) / (2 x wall thickness)

RV is naturally thin walled - ↓thickness, ↑wall tension

Question 4

Describe RV ischemia due to MI:

• Stunning
• Hypotension
• ↑JVP

Answer 4

Stunning = RV not contracting, conduit only, temporary - will recover
Hypotension due to stunning
↑JVP as fluid backs up into venous system

Question 5

What kind of MI leads to systolic dysfxn?

Answer 5

Inferior - leads 2, 3, avF

R coronary artery

Question 6

Treat (do and do not use) RV ischemia due to MI:

• Preload
• Contractility
• Afterload

Answer 6

Preload - + fluids, the only situation you do NOT diurese the ↑JVP
Contractility - inotropes to maintain SV
- **Only during decomp states (dilated)
Afterload - do NOT use systemic vasodiltors

Question 7

What kind of RV F does a PE cause? Include mechanism.

Answer 7

Acute RV F

↑P -> ↑wall tension

Question 8

Treat acute RV F due to a PE

Answer 8

1. Anti-coag
2. Diuretics to ↓preload
3. ↑contractility
4. Pulm arterial vasofilators to ↓afterload

Question 9

2 drugs can use to ↑contractility of RV - include mechanism of each

Answer 9

Dobutamine - B1 > B2 agonist (↑cAMP)

Milrinone - PDE I, prevent cAMP breakdown

Question 10

How does wall thickness change with pulm HTN - compensated –> decomp?

Answer 10

Pulm HTN is ↑P to RA –> immediate ↓SV so to regain SV:
Comp = ↑wall thickness
Depcom as vessel lumen gets even smaller = dilation
Net dilation

Question 11

Symptoms of chronic RV F

Answer 11

“Fluid retention + ↓CO”
Dyspnea, fatigue, lethary
Exertional syncope
Anorexia - ab swelling - edema

Question 12

PE for chronic RV F

Answer 12

Loud P2 = pulmonic component of S2
RV heave
Tricupid regurg murmur 
↑JVP
Hepatomegaly

Question 13

What is cor pulmonale

Answer 13

RV F due to chronic lung disease

• COPD
• Interstitial lung disease
• Pulm fibrosis

Question 14

Treat cor pulmonale

Answer 14

+O2 but only if hypoxic
Diuretics
↓Na diet

Question 15

Why add O2 forRV F due to chronic lung disease

Answer 15

Chronic hypoxemia can worsen pulm HTN –> worse remodeling

Question 16

Do you give ACE I or BB for RV F?

Answer 16

NO

If also have HTN or LV F, there is evidence for that

Question 17

Tricuspid regurg

• Symptoms
• Mechanism
• Treat

Answer 17

Symptoms: probably none!
Mech: likely b/c RV dilated for other reasons compromising valve fxn
Treat:
- ↓RV dilation 
- Not going to repair a tricuspid

Question 18

Decomp or comp - use inotropes

Answer 18

Decomp - dilated