Cardiac Pathology

Question 1

Difference between Angina and a Myocardial Infarction?

Answer 1

Angina is the pain associated with ischaemia, but blood is restored before there is any necrosis of the myocardium. Angina is caused by a transient ischaemia attack (mild stroke). myocardium infarction = heart attack when heart expereinces ischemia & hypoxia

Question 2

Describe the inflammation & repair that occurs following an MI.

Answer 2

Acute inflammation, healing through organization

Question 3

Briefly describe what complications can occur following an MI.

Answer 3

Rupture through in pericardial sack, can get pericarditis. Scar tissue causes a weak point more likely to cause an aneurysm. The aneurysm can rupture or cause a thrombus. More likely to have heart failure or another MI

Question 4

Causes of Left Heart Failure

Answer 4

systemic hypertension from atherosclerosis, renal disease, a large aortic aneurysm), aortic mitral valve diseases, Ischaemic heart disease.

Question 5

Causes of Right heart Failure

Answer 5

Left-sided heart failure & pulmonary disorders like emboli and COPDs like emphysema.

Question 6

Backward effects of Left sided Heart Failure & Symptoms

Answer 6

Pulmonary congestion. Congestion leads to an increase in hydrostatic pressure which leads to oedema. This will make it more difficult for the individual to breathe (dyspnoea) particularly when they are lying down.

Question 7

Backward effects of right sided Heart failure & symptoms

Answer 7

congestion and peripheral oedema with cyanosis. visible signs are likely to be oedema of the legs and ascites but internally, organs that contribute a lot of venous blood to the inferior vena cava (liver, kidneys) will experience congestion and injury including necrosis

Question 8

Forward effects of heart failure

Answer 8

Activation of RAAS by kidneys  reduced cardiac output resulting in renal compensation (make sure you know what angiotensin & aldosterone does  helps maintain cardiac output). Same for left and right.

Question 9

What is Endocarditis

Answer 9

inflammation of inner layer of the heart including the valves

Question 10

Common Causes of Endocarditis

Answer 10

an infection spread through your bloodstream and attaches to damaged areas in your heart.

Question 11

Possible Consequences of Endocarditis

Answer 11

heart valve damage and heart failure, stroke, clot, kidney damage.

Question 12

What is Pericarditis?

Answer 12

Inflammation of the pericardium, the sack surrounding the heart.

Question 13

Causes of Pericarditis?

Answer 13

Infection, autoimmune disease, secondary cancer, uraemia or spread of the inflammatory response caused by a myocardial infarction.

Question 14

Consequences of Pericarditis?

Answer 14

Pain, constrictive pericarditis, and cardiac tamponade, which reduces diastole, stroke volume and cardiac output potentially leading to failure.

Question 15

What impact does aging have on the cardiovascular system?

Answer 15

Ageing is a risk factor for atherosclerosis which in the systemic circuit makes the left ventricle work harder and in the coronary arteries predisposes the heart to ischaemic heart disease. All of our functional tissue atrophies with age, this can be harder to see in the heart as the remaining cells often hypertrophy nevertheless there is reduced functional reserve. Frequently capillary beds become less dense, mitochondria less efficient at generating ATP and neutralising free radicals. There is fewer elastic fibres and more collagen leading to a heart that is more stiff and the valves can become calcified

Question 16

What is Atherosclerosis and what vascular pathology does it cause?

Answer 16

A chronic inflammatory process within the wall of an artery. It predisposes towards the formation of an aneurysm, thrombus/embolus

Question 17

Main risks for the development of atherosclerosis?

Answer 17

Diabetes (due to the hyperglycaemia), increasing age, being male, smoking, systemic hypertension, hyperlipidaemia (increased LDL & reduced HDL). Note that the aboriginal and Torres Strait Islander populations are at heightened risk.

Question 18

How does atherosclerosis contribute to systemic hypertension?

Answer 18

by reducing vessel contractility and increasing resistance to blood flow.
Atherosclerosis can directly injure the kidney and increase RAAS activity, which in turn results in greater systemic hypertension from the increase in blood volume and increased vascular resistance

Question 19

How does systemic hypertension lead to atherosclerosis?

Answer 19

Systemic hypertension encourages turbulent blood flow, which in turn increases the chance of endothelial in jury.

Question 20

How can large aneurysms place greater stress on the heart?

Answer 20

The formation of an aneurysm results in a pocket of lost space that increases the workload of the heart as blood is diverted from its more efficient luminal flow into the out-pouch/aneurysm. The aneurysm can rupture and they can encourage the formation of a thrombus/embolus

Question 21

What does the kidney do in response to hypotension?

Answer 21

In response to a real or perceived fall in blood pressure/cardiac output the kidneys activate the renin-angiotensin II-aldosterone system (RAAS), which results in:
Aldosterone increases sodium and water reabsorption by the kidney  increasing blood volume
Angiotensin II leads to vasoconstriction  increased vascular resistance

Question 22

What does the kidney do in response to hypertension?

Answer 22

activation of RAAS which further increases blood pressure.
Aldosterone increases sodium and water reabsorption by the kidney  increasing blood volume
Angiotensin II leads to vasoconstriction  increased vascular resistance

Question 23

Can you think of a reason why evolution favored such a sensitive response to hypo-tension rather than hypertension?

Answer 23

Natural selection favours qualities/traits that enhance reproduction not ageing. Without medical assistance the birthing process is a very dangerous endeavor due to the risk of infectious disease and hemorrhage. The high estrogen levels of pregnancy favor blood clotting and the response of our bodies to hypo-tension is lifesaving if we suffer a significant hemorrhage.

Question 24

In a person with ischaemic heart disease, which vessels are affected by atherosclerosis?

Answer 24

Coronary Arteries

Question 25

What is congestive heart failure?

Answer 25

A clinical syndrome that can result from any structural or functional cardiac disorder that impairs the ability of the ventricle(s) to fill with or eject blood thus resulting in congestion of blood trying to enter the failing ventricle and reducing the amount of blood being ejected with each contraction.

Question 26

What effect does left ventricular failure have on the right ventricle?

Answer 26

The pulmonary congestion will increase resistance to blood flow entering the lungs (pulmonary hypertension), which in turn places a greater workload on the right ventricle. In response to the greater workload, the right ventricle will hypertrophy and then fail

Question 27

Why does endocarditis frequently become chronic in nature?

Answer 27

The heart valves have a poor blood supply, so the acute response is frequently inadequate, so inflammation becomes chronic.

Question 28

Why is endocarditis a challenge to treat?

Answer 28

Being largely acellular, the valves of the heart do not have a rich blood supply of their own and so it is hard to get a sufficient concentration of neutrophils or drug to the site of infection. In addition, platelets and blood proteins like fibrin can coat the vegetations making them harder to penetrate.

Question 29

What local (within the heart) effects can endocarditis have?

Answer 29

Damage and scarring to the valves, chronic inflammation inevitably results in more tissue damage and scarring/organization.
Valve Stenosis – valves not opening correctly
Valve insufficiency/incompetence – valves not closing correctly so allowing regurgitation
Depending upon which valve is affected, these problems can lead to left, right or global heart failure

Question 30

What other pathology may infective endocarditis cause?

Answer 30

Apart from the systemic effects of heart failure, infective endocarditis can result in infectious emboli being shed into the circulation leading to infarction and infection in organs like the lungs, liver, kidneys, bones, and brain.

Question 31

What backward effects do both right and left sided heart failure heave?

Answer 31

Both result from the ventricle no longer being able to eject blood as effectively so we see more blood remaining in the ventricle following contraction. The blood backs up first in the atria and then in the veins before leading to congestion. Congestion increases hydrostatic pressure causing oedema.

Question 32

Summary of backward effects of left sided heart failure

Answer 32

the congestion & oedema is occurring in the lungs producing a cough, difficulty in breathing and blood-tinged sputum

Question 33

summary of backward effects of right sided heart failure

Answer 33

the congestion & oedema is occurring in the venous system, producing congestion & necrosis in organs with a large outflow into the vena cava (liver & kidneys), swollen legs & ascites

Question 34

Symptoms of left sided heart failure

Answer 34

Dyspnoea (difficulty in breathing) especially when lying down, coughing up blood-tinged fluid.
Note: This will increase pulmonary resistance causing right ventricular hypertrophy

Question 35

Symptoms of right sided heart failure

Answer 35

Severe swelling of the lower limbs, ascites & distended jugular vein
Note: There will be congestion & necrosis in organs with a large venous outflow including the liver & kidneys

Question 36

which organs are at risk of damage in a patient with right sided-heart failure?

Answer 36

Organs with a large outflow into the inferior vena cava typically the liver & kidneys

Question 37

which organs are at risk of damage in a patient with left-sided heart failure?

Answer 37

Lungs, from the chronic congestion and haemorrhaging; right side of the heart due to pulmonary hypertension