Flashcards in Myocardial Infarction Deck (26):
What is a myocardial infarction?
A heart attack
When a blockage stops blood flow through the coronary arteries of the heart, meaning that the heart muscles are starved of oxygen and eventually die.
What two types of MI can be distinguished on an ECG?
Draw the ECG of each type.
ST elevation (the ST segment is raised)
Non-ST elevation (the ST segment is normal
What are the symptoms of an MI?
Cardiac chest pain:
- gradual onset
- severe (usually)
- occurs at rest
- radiates to left arm, jaw, neck
Nausea & vomiting
What are the signs of an MI?
Impending sense of doom
Signs of heart failure
Where to 1/3 of all MIs occur?
In bed at night
What are the causes of MI?
Rupture of an atherosclerotic plaque that leads to formation of thrombus
Dissection of coronary artery
Thoracic aortic dissection
What could cause dissection of coronary arteries?
A disorder of connective tissue, such as Marfan's syndrome
What are the risk factors for MI?
Family history of CHD
L ventricular systolic dysfunction
What lifestyle factors increase MI risk?
Type A personality: more highly strung people
What is the pre-hospital management of a patient with a suspected MI?
Call an ambulance
Paramedics do an ECG: if it shows ST elevation they contact the PCI unit in advance so they can prepare for the patient
Give 300mg aspirin
Give pain relief: morphine
What does STEMI stand for?
ST elevation MI
What does NSTEMI stand for?
Non-ST elevation MI
Which is worse? A STEMI or a NSTEMI?
What is the acute management of a confirmed STEMI?
Attach ECG to monitor heart
Oxygen therapy if hypoxic
Continue pain relief: narcotics & nitrates
Restore coronary perfusion:
PCI or fibrinolysis
What is troponin?
A complex of three regulatory proteins:
- Troponin C
- Troponin I
- Troponin T
What does troponin do?
Integral to muscle contraction in skeletal & cardiac muscle
What do raised troponin levels mean?
Cardiac muscle cell death
Troponin is released into the blood upon cardiac injury
What is PCI?
Percutaneous coronary intervention
Fitting of a stent in the blocked coronary artery to restore blood flow through it
Ideally, in what time period should someone with an MI have PCI?
Within 120 mins of first medical contact
What is fibrinolysis?
Breaking down the clot
Drugs that break down the clot
Ideally, in what time period should someone with an MI receive fibrinolytic drugs?
Within 30 mins of admission
What is the management of a confirmed NSTEMI?
Admit to CCU
ECG while in pain
Give oxygen if hypoxic
Analgesia: narcotics or nitrates
Oral beta blocker: eg. metoprolol
Anticoagulant: aspirin or clopidogrel
Monitor for any changes, such as ST elevation or raised troponin. If these occur consider reperfusion therapy
Do raised troponin levels definitely confirm an MI?
Troponin can be raised for other reasons.
So take a history as well to confiorm MI
What reasons can troponin be raised?
Gram -ve sepsis
What tests should be done in a suspected MI?
FBC, U&E, glucose, lipids
Troponin levels are raised if there is myocardial necrosis
CXR: look for cardiomegaly