Management of Acute Coronary Syndrome Flashcards
What is Angina?
A clinical syndrome caused by insufficient oxygen delivery to the heart muscle, leading to ischemia. It results from an imbalance between increased demand and decreased supply, often due to atherosclerotic plaques in coronary arteries.
What is ischemia?
Restriction of blood flow
What does decreased supply cause?
Coronary plaque perfusion
Decrease perfusion pressure
Decrease arterial oxygen content
What is the most common symptom of an angina?
Constricting discomfort in the front chest; radiating to neck, jaw and left arm.
What does an increase demand cause?
Increase heart rate
Increase pre-load
Increase after-load
Increase contractility
What are the aims of treating angina?
Relieve symptoms,
Prevent or slow disease progression,
Prevent further cardiac events, and improve survival and quality of life.
What are the characteristics of stable angina?
Precipitated by exertion or extreme temperatures, relieved by rest or nitrates, with a set pattern of triggers. It involves long-term management to prevent attacks and reduce the risk of coronary artery disease.
What defines unstable angina?
An acute coronary syndrome characterized by sudden worsening of symptoms, no/minor ECG changes or troponin rise, and less responsiveness to treatment. It can progress to myocardial infarction (MI).
What are Acute Coronary Syndromes (ACS)?
A spectrum of conditions including unstable angina, Non-ST Segment Elevation Myocardial Infarction (NSTEMI), and ST-Segment Elevation Myocardial Infarction (STEMI).
What is the role of troponin in diagnosing myocardial infarction?
Troponin levels rise 4-8 hours after MI onset, peak at 18-24 hours, and remain elevated for up to 10 days, allowing late diagnosis and detecting re-infarctions.
Why do troponin levels rise?
Infarction to the myocardiocytes. Necrosis causes troponin to be released into the bloodstream.
What characterizes a STEMI?
A plaque rupture leading to thrombosis, causing irreversible necrosis of heart muscle due to a long interruption in blood supply.
What changes do you see on an ECG for a STEMI?
ST segment elevation.
What distinguishes a Non-STEMI?
Myocardial necrosis with risk of progression to a STEMI, but with blood flow still present. Treatment focuses on relieving ischemia and preventing further MI or death.
Partial occlusion.
What changes do you see on an ECG for NSTEMI?
ST segment drop.
What is subendocardial ischemia?
Myocardial damage which is often confined to the deep (subendocardial) layer of left ventricular muscle - only subendocardial is affected.
What happens to the wall when a coronary artery is occluded?
Entire wall thickness from endocardium to epicardium is affected.
What are the key medications used in cardiovascular disease?
Antiplatelets, anticoagulants, fibrinolytics, beta-blockers, ACE inhibitors, calcium channel blockers, statins, and others like nicorandil and ivabradine.
How do nitrates work in angina treatment?
They vasodilate arteries and veins, improving coronary blood flow, reducing myocardial workload, and decreasing oxygen demand.
What are the uses of nitrates?
They are used for prophylaxis of angina and acute heart failure.
What are the side effects of nitrates?
Headache,
Flushing,
Hypotension,
Syncope,
Facial flushing,
Postural hypotension
Who are contra-indicated from nitrates?
Acute circulatory failure,
Shock,
Head trauma,
Severe hypotension,
Aortic stenosis
Why is GTN used and how is it administrated?
Short acting
2 x sublingual and every 5 minutes
What is the action of beta-blockers?
They block beta-1 adrenoreceptors, reducing heart rate, force of contraction, and cardiac workload, which lowers myocardial oxygen demand.
What is the use of beta-blockers?
Hypertension,
Angina,
MI
Arrhythmias,
Heart failure
What are the side effects of beta-blockers?
Bradycardia,
Hypotension,
Cold extremities,
Lethargy,
Fatigue,
Impotence,
Precipitate heart failure if poor left ventricular function
What is the role of calcium channel blockers in cardiovascular treatment?
They block calcium access to cells, causing vasodilation and reducing the rate and force of heart contractions. They are used to prevent angina, hypertension, and arrhythmias.
Peripheral vasodilation
Coronary vasodilation
Reduced rate & force of contraction
Who are contra-indicated from beta-blockers?
Asthma
Peripheral vascular disease
Cardiac conduction problems
What do dihydropyridines affect?
Peripheral and coronary vasodilation and act on vascular smooth muscle
What are the two types of calcium channel blockers?
Dihydropyridines & Non-hydropyridines
What do non-dihydropyridines affect?
Affect cardiac conduction, slow the heart rate and act on myocardial tissue.
What are the uses of calcium channel blockers?
Prophylaxis of angina
Prophylaxis of hypertension
Arrhythmias
Used when beta blockers not appropriate
What are the side effects to calcium channel blockers?
Swollen ankles
Headache
Constipation
Flushing
Bradycardia
Oedema
Who are contra-indicated from beta blockers?
Severe hypotension
Heart failure
Sick sinus syndrome
How does aspirin act as an antiplatelet?
Aspirin irreversibly inhibits cyclo-oxygenase, preventing thromboxane production and platelet aggregation for 7-10 days.
What are the uses for aspirin?
Revascularisation to restore sufficient blood flow to affected vessel (reperfusion)
Inhibit clot formation - stop the plaque from getting bigger
Support plaque stabilisation
Secondary prevention of CV disease, TIA, stroke
What are the side effects of aspirin?
Bronchospasms,
GI bleeds,
GI irritation,
Tinnitus
What are the doses of aspirin?
Loading dose 300mg
Low dose 75mg