Cardiac Pathology Flashcards
Difference between Angina and a Myocardial Infarction?
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
Describe the inflammation & repair that occurs following an MI.
Acute inflammation, healing through organization
Briefly describe what complications can occur following an MI.
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
Causes of Left Heart Failure
systemic hypertension from atherosclerosis, renal disease, a large aortic aneurysm), aortic mitral valve diseases, Ischaemic heart disease.
Causes of Right heart Failure
Left-sided heart failure & pulmonary disorders like emboli and COPDs like emphysema.
Backward effects of Left sided Heart Failure & Symptoms
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.
Backward effects of right sided Heart failure & symptoms
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
Forward effects of heart failure
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.
What is Endocarditis
inflammation of inner layer of the heart including the valves
Common Causes of Endocarditis
an infection spread through your bloodstream and attaches to damaged areas in your heart.
Possible Consequences of Endocarditis
heart valve damage and heart failure, stroke, clot, kidney damage.
What is Pericarditis?
Inflammation of the pericardium, the sack surrounding the heart.
Causes of Pericarditis?
Infection, autoimmune disease, secondary cancer, uraemia or spread of the inflammatory response caused by a myocardial infarction.
Consequences of Pericarditis?
Pain, constrictive pericarditis, and cardiac tamponade, which reduces diastole, stroke volume and cardiac output potentially leading to failure.
What impact does aging have on the cardiovascular system?
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
What is Atherosclerosis and what vascular pathology does it cause?
A chronic inflammatory process within the wall of an artery. It predisposes towards the formation of an aneurysm, thrombus/embolus
Main risks for the development of atherosclerosis?
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.
How does atherosclerosis contribute to systemic hypertension?
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
How does systemic hypertension lead to atherosclerosis?
Systemic hypertension encourages turbulent blood flow, which in turn increases the chance of endothelial in jury.
How can large aneurysms place greater stress on the heart?
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
What does the kidney do in response to hypotension?
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
What does the kidney do in response to hypertension?
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
Can you think of a reason why evolution favored such a sensitive response to hypo-tension rather than hypertension?
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.
In a person with ischaemic heart disease, which vessels are affected by atherosclerosis?
Coronary Arteries
