Pathophysiology of Right Heart Failure

Question 1

What is the shape of the right ventricle?

Answer 1

Crescentic

Question 2

Does the RV pump with more or less work than LV?

Answer 2

Less due to low resistance of pulmonary vasculature

Question 3

What are the 3 major portions of the RV?

Answer 3

Inflow, body, outflow

Question 4

Is the stroke volume of the RV bigger or smaller than LV? What about the ejection fraction?

Answer 4

SV is the same!

But ejection fraction is less in RV due to it being more dilated and therefore has a higher EDV

Question 5

What is the contraction pattern of the RV?

Answer 5

Atypical - peristaltic type contraction

Question 6

Does the tricuspid valve have papillary muscles?

Answer 6

No, just chordae that attach to RV wall and three leaflets

Question 7

What is important about the intraventricular septum?

Answer 7

Causes ventricular interdependence

Question 8

What is important about the thickness of the right ventricle in terms of wall tension?

Answer 8

Decreased wall thickness of RV (in comparison to LV) allows smaller changes in pressure and radius to have a bigger effect on wall tension

La Place’s law
Wall tension = (pressure x radius)/2*wall thickness

Question 9

What causes acute RV failure?

Answer 9

Pulmonary thromboembuli
Hypoxia
Capillary leak, causes fluid in lungs
Ischemia (usually RCA)
LV dysfunction

Question 10

What area of the heart can cause RV failure if it gets infarcted?

Answer 10

Inferior myocardial infarction

Usually RCA occlusion

Question 11

Is loss of RV contractile function in the case of inferior ischemia permanent or temporary?

Answer 11

Temporary

Reversible loss of function, even if RCA is completely occluded

Question 12

What happens to jugular venous pressure with RV contractile loss?

Answer 12

Jugular venous pressure increases

Question 13

What is the best way to manage hypotension post RV infarctions?

Answer 13

Fluids

Question 14

What should you not give a patient post RV infarction?

Answer 14

Systemic vasodilators

RV cannot pump and augment SV enough to compensate for the hypotension caused by systemic vasodilators

Question 15

What occurs in the RV when there is a pulmonary embolism?

Answer 15

RV must push harder past clot - pressure overload

Marked increase in wall tension

Question 16

What is the usual treatment for a pulmonary embolism?

Answer 16

Anticoagulants

Question 17

In acute RV failure, what can be done to help with volume management?

Answer 17

In setting of PE or something else that causes RV dilation, may want to use diuretics
- Decongests RV and prevents pressure on LV

In setting of inferior MI, do not use diuretics, would want to give fluids to help with the hypotension

Question 18

How can you enhance contractility in RV failure?

Answer 18

Use inotrope - same as in LV failure

Dobutamine - Beta agonist
Milrinone - PDE inhibitor, increases cAMP by preventing breakdown

Question 19

What are compensation mechanisms of RV failure?

Answer 19

Hypertrophy

Dilation

Question 20

How will the RV compensate for pulmonary hypertension?

Answer 20

Early hypertension (slight thickening of arteries)- RV hypertrophy to maintain SV and CO
Late hypertension (arteries almost occluded) - RV dilated

Question 21

What are the symptoms of chronic RV failure?

Answer 21

Dyspnea
Fatigue, Lethargy - not enough blood flow to brain
Exertional syncope - skeletal vasodilation, not enough blood to brain
Anorexia - venous pressure rises, backs up in liver, stomach, bowel
Abdominal swelling
Edema

Question 22

What are physical exam findings of someone with RV failure?

Answer 22

Loud P2 - usually in case of pulmonary hypertension pushing pulmonary valve closed

RV heave - RV is most anterior and can feel it if dilated or hypertrophic

Tricuspid regurgitation (TR) murmur - increased RV pressure (like in pulmonary hypertension) prevents proper tricuspid closure

Hepatomegaly - liver engorged from blood backup

Increased JVP - from blood backup

Question 23

What is cor pulmonale?

Answer 23

RV failure from chronic lung disease (i.e. COPD or interstitial lung disease)

Question 24

What is the most common treatment for cor pulmonale?

Answer 24

Oxygen if hypoxemic

Diuretics to prevent congestion

Question 25

Should you use ACE inhibitors and Beta blockers in isolated RV failure?

Answer 25

No role for these drugs

Question 26

Why is hypoxia bad for the RV and why is giving oxygen so important?

Answer 26

Leads to pulmonary arteriolar vasoconstriction (an adaptive mechanism to shunt blood away from hypoperfused lung segments to functional ones)

But chronic hypoxemia can lead worsen pulmonary hypertension, and lead to adverse remodeling

Giving oxygen can help prevent this remodeling and RV failure

Question 27

What is the most common cause of RV failure?

Answer 27

LV failure

Question 28

What usually causes tricuspid regurgitation?

Answer 28

Not usually valve pathology, is secondary to ventricular dysfunction

Replacing valve won’t help