Pathophysiology of Heart Failure Flashcards
What factors might increase the work of the heart, leading to heart failure?
Increased O2 demand of tissues
High blood pressure
What are typical clinical signs and symptoms of heart failure?
Signs: raised JVP (>4cm above sternal notch), peripheral oedema, pulmonary oedema, displaced apex beat
Symptoms: breathlessness, ankle swelling, fatigue
How is heart failure pathologically defined?
Abnormality of cardiac structure or function, leading to failure of heart to deliver O2 sufficient enough for requirements of metabolising tissues
What’s the normal balance between hydrostatic and osmotic forces in the cardiovascular system?
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Risk factors for heart disease?
High cholesterol, weight, family history, diabetes, high blood pressure, smoking
Heart failure is a syndrome - what’s the most common underlying cause and other causes?
Coronary artery disease (hardened and narrowed arteries leading to ischaemia)
Valvular heart disease, arrhythmias, high output cardiac failure,
What are the two types of heart failure and how are they classified?
HFrEF(3 criteria) - signs and symptoms of HF + reduced LVEF
HFpEF (4 criteria) - signs and symptoms of HF + normal/mildly reduced EF + relevant structural disease/diastolic dysfunction
What’s an echocardiography?
Ultrasound scan that defines cardiac structure and function - cheap but subjective (good for looking at enlarged left ventricle muscle mass)
Ventricular remodelling is seen in HF - outline the 3 types
Macroscopic - muscle mass loss/atrophy
Microscopic - myocyte changes/disorganised muscle fibre orientation
Intracellular - impaired cell cel communications/contractile protein derangements
Which ventricle is used to define heart failure?
Left - left ventricle reduced ejection fraction in HFrEF
What may cause HFrEF?
Myocardial injury/overload -> impaired contraction
Outline macroscopic, microscopic and intracellular ventricular remodelling
Macroscopic: loss of muscle mass, hypertrophy, dilation
Microscopic: myocyte changes (hypertrophy, necrosis, apoptosis), disorganised muscle fibre orientation, extracellular matrix alterations and inflammatory changes
Intracellular: contractile protein changes, disorganised cytoskeleton, altered metabolism, impaired cell-cell communication
What is ventricular remodelling?
Designed to preserve SV
Chronic pressure overload -> ventricular hypertrophy
MI -> ventricular dilation
What are the 4 classes of heart failure?
Class I - no limitation on physical activity
Class II - comfortable at rest, activity produces mild symptoms
Class III - comfortable at rest but mild activity produces undue symptoms
Class IV - symptoms present at rest, unable to perform any physical activity
Why do you get oedema in heart failure?
Mechanisms cause increased Na+ and H20 reabsorption in the kidneys
Increased venous capillary pressure + reduced plasma oncotic pressure = excavated into ECF
