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Flashcards in Systems Pathology: Heart Failure Deck (11)


Renewing converts angiotensinogen to angiotensin I
ACE converts angiotensin I to II
Aldosterone release
Na retention-> increased blood volume
Cardiac and vascular Hypertrophy


Definition of heart failure

Condition caused by failure of the hearts function as a pump
-> fails to maintain circulation to meet metabolic needs
Clinical manifestations-> fluid congestion and inadequate tissue blood flow
Acute-> failure events happen rapidly
Chronic-> failure compensatory mechanisms


Classification of heart failure

Class I -> no limitation of physical activity
Class II -> slight limitation of activity-> breathlessness/fatigue
Class III -> marked limitation of activity-> breathless on minimal exercise
Class IV -> severe-> symptoms at rest


Cardiac remodelling, molecular changes

Hypertrophy in response to increased demands
Cardiac damage-> ventricular dysfunction
-> cytokines-> heart remodelling
-> Neuroendocrine response-> heart remodelling and symptoms
Pump failure although initially increase output
Adrenergic-> increase contractility and Hypertrophy-> myocycte apoptosis, myocycte toxicity
Angiotensin II-> Hypertrophy-> changed expression of contractile proteins
Cytokines-> Hypertrophy-> remodelling of matrix dilation, dilation-> bad


Left ventricular failure causes

Acute ventricular dysrhythmias
Myocardial infarction and Ischaemic heart disease
Longstanding hypertension
Valve disease
Cardiomyopathies and drugs
Congenital heart disease
-> either increase demand or damage heart
-> insufficient pump power or obstruction of blood flow-> aortic stenosis


Consequences of LVF

Chambers fail to empty at systole-> become dilated
-> progressive rise in pressure in LV which is reflected back into the LA-> Pulmonary veins-> pulmonary capillaries
-> forces fluid out of capillaries-> pulmonary edema-> breathlessness
Also not enough blood pumped out into aorta and arterial system-> hypotension, poor tissue perfusion and poor oxygenation


Clinical examples of LVF

Acute myocardial infarction
Hypertensive heart disease
Chronic rheumatic valve disease


Causes of right ventricular failure

Most common cause is LVF
Acute-> pulmonary thromboembolism
Chronic-> chronic lung disease and pulmonary hypertension
Valve disease is rare


Consequences of RVF

Right chambers dilate-> chambers fail to empty-> raised end diastolic pressure-> increased right arterial and jugular venous pressure-> raised systemic venous pressure
-> tender, large, congested liver
-> peripheral oedema


Clinical examples or RVF

Emphysema-> cor pulmonale
-> destroys alveolar walls-> loss of lung capillaries-> failure of lung ventilation-> hypoxia constricts pulmonary arteries-> pulmonary hypertension


Congestive cardiac failure

Failure of both sides
Most commonly Ischaemic heart disease
LVF then RVF so LVF causes
Cardiomyopathies and drugs
LV aneurysm
Congestive cardiomyopathy

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