Systems Pathology: Heart Failure

Question 0

Definition of heart failure

Answer 0

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

Question 1

RAA

Answer 1

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

Question 2

Classification of heart failure

Answer 2

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

Question 3

Cardiac remodelling, molecular changes

Answer 3

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

Question 4

Left ventricular failure causes

Answer 4

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

Question 5

Consequences of LVF

Answer 5

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

Question 6

Clinical examples of LVF

Answer 6

Acute myocardial infarction
Hypertensive heart disease
Chronic rheumatic valve disease

Question 7

Causes of right ventricular failure

Answer 7

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

Question 8

Consequences of RVF

Answer 8

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

Question 9

Clinical examples or RVF

Answer 9

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

Question 10

Congestive cardiac failure

Answer 10

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