Week 3: Heart Failure Flashcards
What is heart failure?
Heart failure is the inability of the heart to pump enough blood to meet the body’s needs.
What are the two major types of heart failure?
Left Heart Failure (LHF) = Systolic/“Congestive” heart failure.
Right Heart Failure (RHF) = Often due to lung disease.
What causes left heart failure (LHF)?
Mostly caused by ischemic heart disease (e.g., coronary artery disease, heart attacks).
What causes right heart failure (RHF)?
Lung diseases (COPD, pulmonary hypertension).
Left heart failure (LHF) → Blood backs up into the lungs.
How is cardiac output (CO) calculated?
CO = Stroke Volume (SV) × Heart Rate (HR).
In heart failure, CO is reduced, leading to organ hypoxia.
What is preload?
The amount of blood in the ventricles before contraction (end-diastolic volume).
How does preload affect heart failure?
Too much preload overstretches the heart.
The Frank-Starling Law states that increased preload initially helps, but in heart failure, it worsens efficiency.
What is afterload?
The resistance the heart must pump against (e.g., high blood pressure, valve disease).
How does afterload contribute to left heart failure?
Increased afterload (e.g., from hypertension, aortic stenosis) → Left ventricular hypertrophy → Heart failure.
What happens in left heart failure?
Weakened left ventricle → Reduced stroke volume → Low cardiac output.
Fluid backs up into the lungs → Pulmonary congestion & edema.
What is the vicious cycle of left heart failure?
Low cardiac output → Reduced kidney perfusion.
Kidneys activate RAAS → Fluid retention → Increased preload.
More fluid retention → Worsened heart failure symptoms.
What happens to the left ventricle in LHF?
It dilates and undergoes hypertrophy & fibrosis, making it less effective over time.
What are symptoms of left heart failure?
Pulmonary congestion → Shortness of breath (dyspnea), crackles, pulmonary edema.
Difficulty breathing when lying flat (orthopnea).
Fatigue, confusion, cold extremities due to poor circulation.
What happens in right heart failure?
Right ventricle fails to pump blood to the lungs.
Blood backs up into systemic veins, causing fluid retention & swelling.
What are causes of right heart failure?
Left heart failure (most common cause).
Lung diseases (cor pulmonale) → Increased pulmonary resistance.
Tricuspid/pulmonic valve disease → Obstructed blood flow.
What are symptoms of right heart failure?
Peripheral edema (swollen legs, ankles).
Jugular venous distension (JVD).
Hepatomegaly (enlarged liver) & ascites (fluid in the abdomen).
Fatigue & weight gain from fluid retention.
How does the RAAS system worsen heart failure?
Causes Fluid retention & vasoconstriction.
This initially helps but worsens congestion over time.
What role does the sympathetic nervous system (SNS) play in heart failure?
Increases heart rate & contractility to compensate for low output.
Long-term effect: Increases heart workload, worsening failure.
How does ventricular hypertrophy affect heart failure?
Thickened heart muscle increases oxygen demand but reduces efficiency.
What is the NYHA classification of heart failure? (Symptom-based)
Class I: No symptoms with normal activity.
Class II: Symptoms with exertion.
Class III: Symptoms with minimal activity.
Class IV: Symptoms at rest.
What is the ACC/AHA staging system? (Structural-based)
Stage A: Risk factors present (e.g., hypertension, diabetes).
Stage B: Structural heart disease but no symptoms.
Stage C: Structural disease with symptoms.
Stage D: End-stage heart failure.
How is heart failure diagnosed?
Clinical symptoms (dyspnea, fatigue, edema).
Physical exam (lung crackles, JVD, swelling).
Echocardiography (ECHO) to assess ejection fraction (EF).
What is the normal vs. abnormal ejection fraction (EF)?
Normal EF: 55-70%.
Heart failure EF: <40% (systolic failure).
What is the role of BNP in heart failure?
BNP (Brain Natriuretic Peptide) is elevated in heart failure due to ventricular wall stretch.
