Pathology of the Cardiovascular System 1 Flashcards
Atherosclerosis
the process of narrowing within the arteries due to a buildup of fatty plaques over time
Atheroma
fatty plaque deposits consisting of an outer firm shell with a soft inner fatty core.
Ischaemic heart disease
When the coronary arteries become narrowed, blood flow and oxygen supply to the myocardium is reduced
Ischaemia
inadequate blood supply
Chest pain resulting from ischeamic heart disease
angina
Most common symptoms of stable angina
pain or a feeling of discomfort or tightness in the chest, which can often spread to the jaw, back, shoulders and arms
The pain is usually worse on exertion / stress (myocardial demand is higher in these conditions and the heart does not receive enough blood) and relieved after a few minutes on resting.
Shortness of breath is also a common symptom
Risk Factors for IHD:
- Diabetes
- Family history
- High cholesterol
- High blood pressure
- High blood triglycerides
- Obesity
- Physical inactivity
- Smoking
Ischemic heart disease can lead to:
Chronic Angina
myocardial Infarction
congestive heart failure
arrhythmia
Thrombosis
Arteries can become narrower at some locations due to build-up of cholesterol rich deposits
Blood flow can become compromised due to obstructions (plaque) in the lumen of blood vessel
Plaque build up leads to…
Reduced diameter = increased resistance = reduced blood flow in vessel = increases velocity = reduces pressure at the location of the plaque
Can lead to angina/heart attack if occurs in blood vessels leading to heart
Atherosclerosis
is the hardening and thickening of the walls of the arteries
Thrombus
a cellular mass formed within the blood vessel. Composed of platelets, red blood cells, neutrophils and lymphocytes, held together by fibrin derived from the coagulation pathway
Major precipitating event in arterial thrombosis…
Platelet activation at the sites of atherosclerotic plaques
Plaque rupture leads to…
acute thrombosis → acute artery occlusion → tissue death → organ failure → death
Atherosclerotic plaques form due to…
build-up of lipids
If an atherosclerotic plaque ruptures…
thrombus forms which blocks the circulation of blood
Atherosclerosis is a…
progressive disease
Thrombosis =
formation of a blood clot
Thrombosis can lead to…
sudden block of coronary blood supply = heart attack
Over several years a plaque can grow…
obstructs artery which may mean that exercise may result in chest pain = stable angina
The plaque can spontaneously rupture…
the blood system tries to cover up the rupture by sending platelets and coagulation factors → thrombus forms…
the thrombus can cause occlusion of the remaining lumen.
If this occlusion is partial = episode of chest pain (can lead to small heart attack).
Full block = full heart attack.
Myocardial ischaemia…
Lack of blood flow to the heart muscle
no supply of metabolites
loss of oxygen
ATP depletion
loss of calcium homeostasis
calcium concentration becomes high inside cardiac cells
muscle cell cross-bridges remain bound so relaxation cannot occur = they contract to a point where the membrane ruptures and cell death occurs
Overtime this leads to…Cell death
Eventually… Tissue death = area of “infarction”
This leads to… Heart failure
After ischeamia…
Cells can recover with reperfusion depending on how long ischemia took place for
Most common cause of myocardial ischeamia…
the block of the coronary artery (artery that supplied blood to the heart tissue).
Treatment of myocardial ischeamia…
remove the blockage using drugs or Balloon Angioplasty
when the ischemia ends there is reperfusion of tissue that was previously ischemic – however, reperfusion can actually cause further cell damage
At rest, patients with stable angina often have a ……….. ECG
normal
To see signs of myocardial ischeamia on an ECG….
use exercise testing
Treatment for Stable Angina:
A short acting nitrate (GTN spray)
Beta-blocker or calcium channel blocker
Aspirin
Statin
Ace Inhibitor (for those with diabetes)
Anti-hypertensive medication
Prinzmetal’s angina
a form of chest pain, pressure, or tightness caused by spasms in the arteries that supply blood to the heart
a form of unstable angina
Prinzmetal’s angina occurs…
at rest, in contrast to stable angina which usually occurs in a predictable pattern during exertion or exercise.
Symptoms usually occur in clusters, with periods of frequent episodes lasting for a few months followed by weeks or months with no chest pain episodes
The exact cause is unknown, but patients normally have atherosclerosis
The chest pain caused by Prinzmetal’s angina is caused by…
coronary artery spasm (involuntary constriction of the muscle in the artery) which markedly reduces the size of the vessel lumen and restricts blood supply to the myocardium
ECG of Prinzmetal’s angina shows…
ST elevation at the time of symptoms
Unstable angina, Non-STEMI and STEMI all result from…
complete or almost complete thrombotic occlusion of a coronary artery following rupture of an atherosclerotic plaque
NSTEMI and Unstable angina usually result from…
incomplete occlusion of a coronary artery
STEMI is associated with…
complete occlusionof a coronary artery
Unstable angina is …
Unstable angina is a type of chest pain that often doesn’t have a pattern and usually gets worse. Will likely lead to a heart attack.
It happens with only mild physical activity or may happen without warning when you’re at rest, relaxing or even asleep.
Most common cause of unstable angina…
Coronary artery disease due to atherosclerosis
Atherosclerosis is the buildup of fatty material, called plaque, along the walls of the arteries. This causes arteries to become narrowed and less flexible. The narrowing can reduce blood flow to the heart, causing chest pain.
Unstable angina treatments may include:
- Medicines to help blood clots dissolve and stop new blood clots from forming.
- Angioplasty with stent implantation.
- Heart bypass surgery.
Stable angina
- Occurs with physical activity or with anger, anxiety or stress.
- Lasts a short amount of time (usually only a few minutes).
- Occurs regularly or predictably — usually with the same amount of activity or emotional stress every time.
Acute coronary syndrome:
An umbrella term encompassing:
o STEMI
o NSTEMI
STEMI =
ST ELEVATION MYOCARDIAL INFARCTION
NSTEMI =
NON-ST ELEVATION MYOCARDIAL INFARCTION