Cardiac Pathology Flashcards
What is the difference between angina & a myocardial infarction (MI).
Angina —> caused by Transient ischaemia (temporary). Causes pain due to heart muscles anaerobically metabolising and producing lactic acid. Blood flow is restored hence, no necrosis or scarring
Myocardial infarction —> caused by acute ischaemia, leads to chronic heart failure. Necrosis and scarring in the myocardium
Describe the inflammation & repair that occurs following an MI.
Cause acute inflammation
Heals through organisation (in growth of granulation tissue and maturation into collagen
scar)
Briefly describe what complications can occur following an MI
- Chronic heart failure
Due to organisation, loss of function
Cannot conduct electric impulses in the same way (causes arrhythmia)
Does not produce anti-coagulants, prone to thrombus
Not as strong, prone to aneurysm
Describe the causes of left- versus right-sided heart failure (HF).
Left sided heart failure causes:
- Ischaemic heart disease.
- Systemic hypertension.- Aortic/mitral valve disease.
Right sided heart failure causes:
- Left sided heart failure - Elevated resistance within pulmonary circulation
Backward effects and symptoms of Left sided failure
- Reduced venous return from pulmonary circuit.
- Pulmonary congestion- increase in hydrostatic pressure
- Pulmonary oedema
- Dyspnea/cough
What are the ‘forward’ effects of HF i.e. what compensatory mechanisms are triggered from a reduction in cardiac output?
Same for both RHF and LHF Renal response to reduced CO: Reduced renal perfusion. Activation of RAAS. Salt/water retention. Increased blood volume. Increased vascular resistance.
Describe some of the common causes & possible consequences of endocarditis.
Causes - Issue with the valves and innerlinings. Autoimmune, ageing, accumulation of calcium, infective endocarditis
Consequences - Leads to stenosis and incompetence. Therefore, congestive heart failure
Describe some of the common causes & possible consequences of pericarditis.
Causes: Intrinsic HD Disease in lungs, pleura, mediastinum, Generalised disorders Extension of inflammation Secondary deposits of cancer radiation therapy Autoimmune disorder Myocardial infarction
Effects -
Pain
Restricts heart’s ability to move freely
Heart failure
What impact does ageing have on the cardiovascular system?
- Fewer myocytes in older heart
- Hypertrophy occurs
- Stiff connective tissue
- Regression of capillary beds
- Atherosclerosis
- Calcification of soft tissue
Stenosis
Valve does not open properly, increased resistance of flow. Disrupts preload
Incompetence
Valve does not close properly
Aneurysm
an abnormal, localised, dilatation of an artery or ventricle
Types of Hypertension
Systemic
Pulmonary
Portal
Systemic hypertension
Blood pressure throughout the systemic arterial circuit
Blood coursing under high pressure
Dialating artery leads to decreased blood pressure
Pulmonary hypertension
Right sided and in the pulmonary artery system
Portal Hypertension
In the two blood supplies of the liver
Layers of the heart
Endocardium - inner lining of heart, produces anti-coagulants
Myocardium - muscle of the heart
Pericardium - outer part
Systole
contraction of heart
Diastole
relaxation of heart
Cardiac Output
• CO = amount of blood ejected from the ventricles every minute
• CO = indicates cardiac performance
CO = HR x SV (stroke volume)
Heart rate
beats per min
Pre load
volume/ loading conditions after diastole
related to blood volume and venous return
Afterload
force required to eject blood out of the ventricles
related to resistance (constriction of blood vessels)
Eject fraction
% of blood pumped out the ventricles with every contraction (normal = 65%)
Risk factors of Cardiovascular disease
- Smoking
- Male gender
- Increasing age
- Systemic hypertension
- Hyperglycaemia
- Genetics
Atherosclerosis leads to
- Reduced vascular elasticity
- Increased vascular resistance
- Swelling/bleeding in plaque
Atherosclerosis —> vascular pathology
- Thrombus
- Embolus
- Aneurysm - due to weakening
Angina
ischemia with blood flow restored. Heart muscles anaerobically metabolism, produces lactic acid (causes pain). No necrosis and no scarring
Ischaemic Infarction
- Sub-endocardial region most susceptible. inner 1/3 to 1/2.
- Non-Stemi (depressed ST wave in ECG, partial blockage of coronary artery), smaller area than transmural. Some scar and muscle
- Transmural - most common, full thickness of muscle wall has been lost to necrosis. Mostly scarring
Most common artery involved in heart attacks
Right coronary artery - 30% of cases
Left anterior descending artery obstruction - 50%, artery of sudden death
Circumflex artery - 20%
Complications of Myocardial infarction
- Anterior myocardial rupture in an acute infarct, through the muscular wall
- Rupture in the ventricular septum
- Complete rupture of a necrotic papillary muscle
- Exudate fluid build up in pericardial sac, impacts relaxation stage, causes pain
- Greater risk of thrombus formation
- Aneurysm due to differing pressures caused by scar tissues
Congestive Heart Failure
Heart increases in size to meet demands of maintaining blood pressure and cardiac output
- In response to pressure overload; hypertrophy of L.V. (increased wall thickness)
- In response to volume overload: volume of chamber increased. Heart failure
Impact of dysfunction on ejection fraction
• Systolic dysfunction – impaired contractility –>Decreased ejection fraction and CO
Diastolic dysfunction–> Normal ejection fraction but impaired filling – Decreased preload, SV and CO
Backward effects and symptoms of right sided failure
Congestion of blood within venous system leads to:
- Liver/spleen/kidney disease (pressure necrosis).
- Oedema of bowel with production of ascites (fluid collects in spaces within the abdomen).
- Peripheral oedema: swelling of ankles & legs a hallmark feature.
Passive Congestion —> increased hydrostatic pressure —> oedema
Venous system congestion
Infective endocarditis
- made up of connective tissue (avascular), does not have a good acute response
- Bacteria sticks to valve and acute response does not occur
- Antibiotics blocked by platelets and fibrins
- Usually occurs due to age and drug use
- Bacteria can embolise
Valve disease: Rheumatic HD
Autoimmune disease
Straight to chronic
From Strep- A bacteria
Anti body cross reacts and attacks parts of the heart
Can lead to pericarditis, myocarditis, endocarditis
Predispose to Heart failure
Cirrhosis
scarring in the liver
functional units are not functioning and creates resistance and congested
