Pathophysiology of Right Heart Failure Flashcards
What is the shape of the right ventricle?
Crescentic
Does the RV pump with more or less work than LV?
Less due to low resistance of pulmonary vasculature
What are the 3 major portions of the RV?
Inflow, body, outflow
Is the stroke volume of the RV bigger or smaller than LV? What about the ejection fraction?
SV is the same!
But ejection fraction is less in RV due to it being more dilated and therefore has a higher EDV
What is the contraction pattern of the RV?
Atypical - peristaltic type contraction
Does the tricuspid valve have papillary muscles?
No, just chordae that attach to RV wall and three leaflets
What is important about the intraventricular septum?
Causes ventricular interdependence
What is important about the thickness of the right ventricle in terms of wall tension?
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
What causes acute RV failure?
Pulmonary thromboembuli Hypoxia Capillary leak, causes fluid in lungs Ischemia (usually RCA) LV dysfunction
What area of the heart can cause RV failure if it gets infarcted?
Inferior myocardial infarction
Usually RCA occlusion
Is loss of RV contractile function in the case of inferior ischemia permanent or temporary?
Temporary
Reversible loss of function, even if RCA is completely occluded
What happens to jugular venous pressure with RV contractile loss?
Jugular venous pressure increases
What is the best way to manage hypotension post RV infarctions?
Fluids
What should you not give a patient post RV infarction?
Systemic vasodilators
RV cannot pump and augment SV enough to compensate for the hypotension caused by systemic vasodilators
What occurs in the RV when there is a pulmonary embolism?
RV must push harder past clot - pressure overload
Marked increase in wall tension
What is the usual treatment for a pulmonary embolism?
Anticoagulants
In acute RV failure, what can be done to help with volume management?
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
How can you enhance contractility in RV failure?
Use inotrope - same as in LV failure
Dobutamine - Beta agonist
Milrinone - PDE inhibitor, increases cAMP by preventing breakdown
What are compensation mechanisms of RV failure?
Hypertrophy
Dilation
How will the RV compensate for pulmonary hypertension?
Early hypertension (slight thickening of arteries)- RV hypertrophy to maintain SV and CO Late hypertension (arteries almost occluded) - RV dilated
What are the symptoms of chronic RV failure?
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
What are physical exam findings of someone with RV failure?
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
What is cor pulmonale?
RV failure from chronic lung disease (i.e. COPD or interstitial lung disease)
What is the most common treatment for cor pulmonale?
Oxygen if hypoxemic
Diuretics to prevent congestion
Should you use ACE inhibitors and Beta blockers in isolated RV failure?
No role for these drugs
Why is hypoxia bad for the RV and why is giving oxygen so important?
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
What is the most common cause of RV failure?
LV failure
What usually causes tricuspid regurgitation?
Not usually valve pathology, is secondary to ventricular dysfunction
Replacing valve won’t help
