Acute Coronary Syndromes Flashcards
What are the two processes involved in acute coronary syndromes.
Ischaemia - narrowing of the coronary arteries which leads to a reduction in blood supply (nutrients and oxygen)
Infarction - complete obstruction of the coronary arteries leads to tissue necrosis.
What segment of an ECG is abnormal in a heart attack?
S - T segment
What is a common cause of acute coronary syndromes?
Atherosclerosis
List examples of diseases associated with ischaemia of the coronary arteries.
Angina pectoralis
Peripheral vascular disease (angina of the limbs) comes alongside coronary artery disease.
List examples of diseases associated with infarction of the coronary arteries.
Myocardial infarction
What is angina?
Reversible ischaemia (reduction in blood supply) to the heart muscle.
What causes angina?
Narrowing of the coronary arteries - atherosclerosis.
What are the symptoms of angina?
Crushing chest pain
Pain radiates down arm, up neck and into jaw.
Tightness
What are the types of angina?
Classical - pain on exertion
Unstable - pain occurs at rest
What are the aims of angina/acute coronary syndrome treatment?
To reduce oxygen demands
i.e. reducing preload and afterload via blood pressure.
To increase oxygen delivery
i.e. via angioplasty or coronary artery bypass (CABG)
What are the non-drug therapies for angina/acute coronary syndrome?
Educating the patient so that they live within limits
Modifying lifestyle factors;
Stop smoking
Healthy diet
Exercise programmes to encourage blood flow to the tissues.
What are the drug therapies for angina/acute coronary syndrome?
Nitrates: Dilate veins, and resistance arteries (coronary arteries)
Glyceryltrinitrate - short acting
isosorbide mononitrate - long acting
Aspirin - anti platelet: reduced risk of complete obstruction and infarction.
ACE inhibitors - reduce hypertension by reducing vasoconstriction.
Beta blockers - reduce force of contraction and excitability of cardiac muscle. Prevent arrhythmias.
Ca channel blockers - relax smooth muscle and cause vasodilation to reduce hypertension.
Diuretics - reduce hypertension by reducing salt and water, plasma volume and ultimately the cardiac workload.
What are the surgical therapies for angina/acute coronary syndrome?
Angioplasty and stenting - dilate the obstructed/narrowed vessels.
CABG - Bypass the obstruction/narrowing
When is angioplasty/stenting especially useful?
In treating a STEMI (S - T elevation myocardial infarction: where major artery supplying the heart muscle is blocked)
In what type of patient is a CABG especially useful for?
Elderly patient - the bypass is only beneficial for 10 years.
This could be contra-indicated by a frail elderly individual as the surgery is risky and requires the heart to be stopped and restarted.
What are the diagnostic tools used in acute coronary syndromes?
Troponin biomarkers - released into the blood when the heart muscle is damaged.
ECG:
STEMI
NSTEMI
S-T segment is elevated in an individual having a myocardial infarction which means there is complete obstruction of a coronary artery.
What is peripheral vascular disease?
Angina (reversible ischaemia) of the peripheral tissues - usually lower limbs
What is peripheral vascular disease commonly associated with?
Coronary artery disease.
What vessels are commonly affected in peripheral vascular disease?
Femoral and popliteal (back of the knee)
What is the pain associated with peripheral vascular disease called?
Claudication
How do you manage peripheral vascular disease?
Managed the same as angina.
Non- drug therapy: Modifying lifestyle factors; Stop smoking Healthy diet Exercise programmes to encourage blood flow to the tissues.
Drug therapy:
Nitrates: Dilate veins, and resistance arteries (coronary arteries)
Glyceryltrinitrate - short acting
isosorbide mononitrate - long acting
Aspirin - anti platelet: reduced risk of complete obstruction and infarction.
ACE inhibitors - reduce hypertension by reducing vasoconstriction.
Beta blockers - reduce force of contraction and excitability of cardiac muscle. Prevent arrhythmias.
Ca channel blockers - relax smooth muscle and cause vasodilation to reduce hypertension.
Diuretics - reduce hypertension by reducing salt and water, plasma volume and ultimately the cardiac workload.
Surgical:
Angioplasty and stenting - dilate the obstructed/narrowed vessels.
What is there a high risk of in patients with peripheral vascular disease?
Myocardial infarction
Poor wound healing = Tissue necrosis and gangrene = amputation
Describe the process of ischaemia becoming infarction.
Atherosclerosis (cholesterol deposits in the vessel walls) becomes an atheroma when the immune system attacks the cholesterol in the walls and the damaged endothelial cells are repaired with fatty scar tissue.
The damaged cells become permeable and release thrombogenic factors which encourages platelet aggregation on the surface of the atheroma.
This aggregation grows rapidly to create a complete obstruction.
This blockage can break off and cause embolism.
What are the 5 types of myocardial infarctions?
Spontaneous MI - plaque rupture
MI secondary to ischaemia
Sudden death
MI from percutaneous coronary intervention (angioplasty with stent)
MI from CABG
What are the signs and symptoms of a myocardial infarction (acute coronary syndrome)?
Chest pain - radiates
sweating
palor
nausea
Can also be silent - patient is unaware.
Why are autonomic symptoms i.e. nausea present in an MI?
The pain goes through the basal ganglion in the thalamus.
What are the complications of a myocardial infarction?
Death
Functional limitation from death of cardiac muscle = heart failure.
Arrhythmias
Ventricular hypofucntion
Valve disease from papillary muscle rupture
What are the investigations for a myocardial infarction?
ECG:
S - T elevation
T wave abnormalities
Q wave detects previous MI’s
Will dip lower then normal base line.
Cardiac enzymes present in blood:
Troponin
Creatinine kinase.
What are the treatment options for a myocardial infarction?
Angioplasty and stent.
Thrombolysis (dissolving the clot) using streptokinase and TPA.
CABG
What is the time window for an angioplasty/stent after a patient has had an MI?
3 hours
What is the time window for thrombolysis after a patient has had an MI?
6 hours
What is the most effective treatment option after an MI?
Angioplasty/stent
What are the contraindications to using thrombolysis to treat an MI?
Recent surgery Recency significant injury Severe hypertension Diabetic eye disease liver disease pregnancy
What drugs are used to prevent further episodes of acute coronary syndrome?
Aspirin - anti platelet: reduced risk of complete obstruction and infarction.
ACE inhibitors - reduce hypertension by reducing vasoconstriction.
Beta blockers - reduce force of contraction and excitability of cardiac muscle. Prevent arrhythmias.
What is another name for an infarction in the brain?
A stroke
What usually causes a stroke?
An obstruction caused by embolism (clot from an atheroma at a different site)
Why is a stroke rarely caused by vessel thrombosis?
Brain has good collateral blood supply
What is the common outcome of a stroke?
Loss of function
Dependant on which area is affected by the obstruction.
What is a transient ischaemic attack?
a ‘mini stroke’ - temporary disturbance to the brains blood supply that fully resolves itself within 24 hours.
What is the difference between a heart attack and a cardiac arrest?
Heart attack - ‘circulatory’ problem
Blood flow to the cardiac muscle is obstructed.
Cardiac arrest - ‘electrical’ problem
Heart beat malfunctions stops beating/beats chaotically.
