Week 3 topic 3 Flashcards
(30 cards)
What is congestive heart failure (CHF)?
CHF results from structural or functional disorders that impair ventricular filling or ejection of blood into the systemic circulation.
How is heart failure classified?
Depending on the side of the heart affected:
- left or right heart failure
Depending on the cardiac dysfunction:
- systolic or diastolic heart failure
What characterizes systolic heart failure?
Impaired myocyte contractility leading to reduced stroke volume and ejection fraction.
What characterizes diastolic heart failure?
Impaired relaxation of ventricles that results in reduced filling, leading to reduced stroke volume and ejection fraction.
What is the most common cause of heart failure?
Myocardial infarction due to coronary artery disease.
List some causes of heart failure.
- Ischemic heart disease
- Valvular heart disease
- Pulmonary causes
- Cardiomyopathies
- Arrhythmias
- Collagen vascular disease
- Endocrine disorders
- Toxins - cocaine and alcohol
What are the primary causes of left heart failure?
- Ischemic heart disease
- Hypertension
- Aortic and mitral valvular diseases
- Myocardial diseases
What are the clinical effects of left-sided CHF caused by?
- Passive congestion - blood backing up in pulmonary circulation
- Stasis of blood in left heart chambers
- Inadequate perfusion of downstream tissues leading to organ dysfunction
What is forward failure in left heart failure?
Reduced stroke volume and cardiac output that cannot meet metabolic demand, leading to fatigue, hypotension, tachycardia, syncope, and oliguria.
What is backward failure in left heart failure?
Blood backs up into the lungs causing pulmonary congestion, leading to dyspnea, orthopnea, and chest pain.
List non-modifiable risk factors for heart failure.
- Age
- Male sex
- Family history of heart failure
- Ethnicity (higher incidence in blacks)
What are some medical conditions that increase the risk of heart failure?
- Coronary artery disease
- Diabetes
- Hypertension
- Obesity
- Valvular heart disease
What are some unhealthy lifestyle factors that contribute to heart failure?
- Smoking tobacco
- Excess alcohol
- Mental stress
- Sedentary lifestyle
- Unhealthy diet
What gross features are seen in the lungs during left heart failure?
Lungs are edematous.
What microscopic features are seen in the lungs during left heart failure?
- Edematous alveolar septa
- Congested blood vessels
- Accumulation of fluid in alveolar spaces
- Heart failure cells (macrophages phagocytose extravasated RBCs and break them down releasing hemosiderin )
What are some findings on a chest X-ray for acute left heart failure?
- Severe pulmonary edema
- Cardiomegaly
- Increased vascularity
- Kerley lines
- Pleural effusion
What causes right heart failure?
- Reduced contractility of right ventricle from MI, cardiomyopathy and tricuspid regurgitation
- Increased afterload of right ventricle due to left heart failure, pulmonary hypertension and fibrosis
What is the result of right heart failure?
Blood backs up into systemic venous circulation, leading to jugular venous distension, ascites, peripheral edema, hepatosplenomegaly and splanchnic congestion leading to anorexia and weight loss (cardiac cachexia)
What is congestive hepatomegaly?
Increased size and weight of the liver due to congestion.
What are compensatory mechanisms in heart failure?
- Decreased stretch of baroreceptors causes activation of sympathetic nervous system to increase HR, contractility and vasoconstriction
- Activation of RAAS
- Release of anti-diuretic hormone (ADH) - water retention
- Release of atrial natriuretic peptide (ANP) - diuresis and vasodilation
Fill in the blank: Right heart failure causes _______ and peripheral edema.
ascites
True or False: Left heart failure can lead to pulmonary congestion.
True
What causes systolic dysfunction in left heart failure
Reduced left ventricle contractility due to MI, aortic or mitral valve regurgitation or dilated cardiomyopathy
What causes diastolic dysfunction in right heart failure
Increased afterload in hypertension or aortic stenosis leads to left ventricular hypertrophy which impairs the relaxation of the left ventricle causing elevated end diastolic pressures
Hypertrophic cardiomyopathy - resistance to the left ventricle outflow that causes increase left ventricle pressure
