Myocardial infarction Flashcards
What is myocardial infarction?
a.k.a. heart attack.
It occurs when there is myocardial necrosis following atherosclerotic plaque rupture, which occludes one or more of the coronary arteries.
Part of the acute coronary syndromes (ST elevation MI, non-ST elevation MI, and unstable angina).
What is the cause of myocardial infarction?
Atherosclerosis.
What are the symptoms of myocardial infarction?
Nausea, sweating, palpitations.
Crushing chest pain for more than 20 minutes.
Can be silent in diabetes.
What are the signs of myocardial infarction?
RIP:
Raised jugular venous pressure (JVP).
Increased pulse, blood pressure changes.
Pallor, anxiety.
What are the different types of infarct?
Transmural and subendocardial.
What is a transmural infarct?
Affects all of the myocardial wall.
ST elevation and Q waves.
What is a subendocardial infarct?
Necrosis of <50% of the myocardial wall.
ST depression.
What investigations are performed for suspected myocardial infarction?
ECG, may show: ST elevation, ST depression, inverted T waves, new left bundle branch block (LBBB), pathological Q waves.
CXR, may show: cardiomegaly, pulmonary oedema, widening of the mediastinum.
Bloods: look for cardiac biomarkers troponin I and troponin T.
Angiography with the view to perform percutaneous coronary intervention (PCI).
What is the conservative treatment for myocardial infarction?
Lifestyle measures such as smoking cessation and increased exercise.
What is the medical treatment for myocardial infarction?
Morphine, oxygen (if hypoxic), nitrates (glyceryl trinitrate GTN), anticoagulants (e.g. aspirin and an antiemetic), beta-blockers if no contraindication.
On discharge all patients should be prescribed aspirin, an ACE inhibitor, a beta-blocker (or calcium channel blocker if contraindicated), and a statin.
What is the surgical treatment for myocardial infarction?
Reperfusion with PCI if STEMI.
PCI may also be used in NSTEMI but if NSTEMI patients are not having immediate PCI, fondaparinux (factor Xa inhibitor) or a low molecular weight heparin may be given subcutaneously.
What are the complications of myocardial infarction?
Cardiogenic shock Cardiac arrhythmia Pericarditis Emboli Aneurysm formation Rupture of ventricle Dressler's syndrome Rupture of free wall Papillary muscle rupture
