week 8 heart failure Flashcards
- Name two major causes of heart failure with reduced ejection fraction (HFrEF).
Model Answer:
* Ischemic heart disease (myocardial infarction)
* Dilated cardiomyopathy
Other causes include aortic stenosis, mitral/aortic valve regurgitation, and viral myocarditis (e.g., COVID-19).
- What is ejection fraction (EF) and how is it calculated?
Model Answer:
Ejection fraction is the percentage of blood ejected from the left ventricle with each contraction.
It is calculated as:
EF(%)=EDV−ESVEDV×100EF (\%) = \frac{EDV - ESV}{EDV} \times 100
where EDV = end diastolic volume, and ESV = end systolic volume.
A healthy EF is typically between 50% and 70%.
- What changes occur in the heart post-myocardial infarction leading to HFrEF?
Model Answer:
* Increased end-diastolic volume (EDV) due to ventricular dilation.
* Markedly increased end-systolic volume (ESV) due to poor contraction.
* Formation of scar tissue replacing dead cardiomyocytes.
* Decreased ejection fraction (<40%).
. Describe the phases of immune response following myocardial infarction.
Model Answer:
* Inflammatory Phase (0–3 days):
o Death of cardiomyocytes releases DAMPs (danger-associated molecular patterns).
o Recruitment of neutrophils and pro-inflammatory monocytes.
o Differentiation into M1 macrophages that degrade tissue using matrix metalloproteinases (MMPs).
* Proliferative Phase (3–7 days):
o Increase in fibroblast proliferation and differentiation into myofibroblasts.
o Shift of monocytes/macrophages from M1 to reparative M2 phenotype.
* Maturation Phase (weeks):
o Scar tissue formation with cross-linking collagen.
o Loss of contractile function.
- Discuss why anti-inflammatory and anti-fibrotic therapies after myocardial infarction have been disappointing in clinical translation.
Model Answer:
Although promising in animal models, anti-inflammatory and anti-fibrotic therapies often failed clinically because:
* Complete suppression of inflammation can impair necessary tissue clearance and early healing.
* Timing of intervention is critical but difficult to optimize in heterogeneous human patients.
* Some anti-inflammatories exacerbated infarct size or increased major adverse cardiac events (MACE).
- What is the major cause of post-MI scar tissue formation?
A) Proliferation of cardiomyocytes
B) Differentiation of fibroblasts into myofibroblasts
C) Accumulation of neutrophils
D) Endothelial cell proliferation
Correct Answer: B) Differentiation of fibroblasts into myofibroblasts
- Which of the following therapies involves using a patient’s own cells to regenerate heart tissue?
A) Embryonic stem cells
B) Induced pluripotent stem cells (iPSCs)
C) Anti-fibrotic drugs
D) Coronary artery bypass grafting (CABG)
Correct Answer: B) Induced pluripotent stem cells (iPSCs)
- In heart failure with preserved ejection fraction (HFpEF), which cardiac function is primarily impaired?
A) Systolic contraction
B) Diastolic relaxation
C) Heart rate
D) Valve closure
Correct Answer: B) Diastolic relaxation
- Explain why HFpEF is harder to diagnose compared to HFrEF.
Model Answer:
In HFpEF, ejection fraction remains normal (≥50%), so standard EF measurement cannot detect the dysfunction. Diagnosis relies on additional factors such as:
* Evidence of diastolic dysfunction via echocardiography (e.g., E/A and E/e’ ratios).
* Clinical signs like lung congestion, exercise intolerance.
* Risk factor scoring (e.g., hypertension, obesity, thickened LV wall).
- Why is ejection fraction preserved in HFpEF patients?
A) Because the heart contracts poorly
B) Because both EDV and ESV are reduced proportionally
C) Because the thickened wall maintains contraction but impairs relaxation
D) Because stroke volume is increased
Correct Answer: C) Because the thickened wall maintains contraction but impairs relaxation
