Chronic Heart Failure Flashcards
What is chronic heart failure?
It is a complex clinical syndrome with typical symptoms (e.g. dyspnoea, fatigue) that can occur at rest or on effort, and is characterise dby objective evidence of an underlying structural abnoramlity of cardiac dysfunction that impairs the ability of the ventricle to fill with or eject blood (particularly during physical activity).
Causes of CHF
The commonest causes of CHF are:
- Ischaemic heat disease: present in over 50% of new cases
- HTN: present in about two-thirds of cases
- Idiopathic cardiomyopathy: around 5-10% of cases.
Systolic heart failure
Characterised by a weakened ability of the heart to contract in systole (depressed ejection fraction)
Diastolic heart failure
Refers to imapired diastolic filling of the ventricle due to poor relaxation or increased myocardial stiffness without impaired systolic contraction (preserved ejection fraction) but may also have depressed ejection fraction.
Right sided heart failure causes
Most commonly caused by left heart failure.
Cor pulmonale
Dilatation and hypertrophy of the right ventricle in respose to diseases of the pulmonary vasculature (including primary pulmonary hypertension, recurrent pulmonary thromboembolism, congenital heart disease with a left to right shunt) or lung parenchymal disease (commonly COPD) that ultimately causes pulmonary HTN.
Pathology of CHF
Left ventricular remodelling ocurs at the cellular and molecular level. Key features include:
- Mycoyte hypertrophy
- Alterations in contraction
- Loss of myocytes
- Changes in response to stimuli - adrenergic and metabolic, reorganisation of the extracellular matrix leading to change in myocyte support.
Pressure overload hypertrophy usually leads to concentric increase in wall thickness. Volume-overload hyperophy is characterised by dilation leading to increased, normal or less than normal wall thickness.
