Acute Coronary Syndrome Flashcards
Define acute coronary syndrome
a spectrum of conditions that involve myocardial ischaemia, includes various types of angina and myocardial infarction with ST-segment changes
How can myocardial infarctions be categorised?
Non-ST elevation myocardial infarction (NSTEMI) and ST elevation myocardial infarction (STEMI)
What is an NSTEMI?
Non-ST elevation myocardial infarction - occurs when thrombus partially or transiently obstructs a coronary artery causing ischaemia and necrosis
What is a STEMI?
ST elevation myocardial infarction - occurs when a thrombus causes complete obstruction of a coronary artery resulting in ischaemia and necrosis
What is angina?
a disease marked by chest pain caused by insufficient oxygenation of the heart. There are three forms of angina: stable, unstable, and prinzmetal/variant
describe stable angina
Occurs as a result of plaque build-up and inappropriate vasocontriction. Also known as exertion angina as blood flow is often adequate at rest but insufficient with exertion, causing pain.
describe unstable angina
occurs when atherosclerotic plaque and an associated thrombus partially obstructs blood flow. Unstable angina differs from stable angina as there is a greater degree of vascular obstruction at rest, compromising blood flow and causing pain without exertion.
Describe prinzmetal/variant angina
occurs as a result of unexplained vasospasm and not atherosclerotic plaque build-up. Prinzmetal angina is not generally triggered by exercise unlike other forms and can occur at any time.
What is a myocardial infarction?
a partial or complete obstruction of a coronary blood vessel resulting in significantly reduced blood flow leading to ischaemia and cell death.
what are the two common reperfusion interventions used in the treatment of an MI?
thrombolysis and percutaneous coronary intervention (PCI)/ fibrinolysis
what is thrombolysis?
the dissolution of a blood clot by infusing throbolytic enzymes (such as plasminogen activator) into the blood
what is percutaneous coronary intervention (PCI)/ fibrinolysis?
the enzymatic breakdown of the fibrin in blood clots
what is the best way to avoid or limit reperfusion injury?
attempt reperfusion as soon as possible
what is the difference between thrombolysis and fibrinolysis?
thrombolysis refers to the breakdown of a thrombus through the action of various agents whereas fibrinolysis refers specifically to the breakdown of fibrin in blood clots
What are the common complications associated with coronary disease?
increased risk of heart failure, dysarrhythmias, MI, chest pain, sudden death
List the clinical manifestations of ACS
- increased HR
- increased RR
- diaphoresis
- nausea
- vomiting
- chest pain (typically described as crushing, central, radiating to arm or jaw)
- syncope
- fatigue
- epigastric pain
- back pain (commonly between scapula)
what is a silent MI?
Essentially a painless MI, common in elderly people who have neuropathic diseases or diabetes who may not feel the expected chest pain
How is ACS diagnosed?
a presumptuous diagnosis can be made based on information such as symptoms, family history, patient history, ECG changes, and observations. A definitive diagnosis requires imaging (such as an angiogram) to confirm the presence of plaques. MI’s are generally diagnosed using cardiac markers (like troponin) that are released as a result of cell death.
what is the pre-hospital management for ACS?
- rapid transport (time is tissue)
- administration of GTN
administration of aspirin - pain management (typically fentanyl or morphine)
- managing dysarrhythmias where possible
- risk elimination once primary needs are managed
is oxygen therapy recommended to treat ACS pre-hospitally?
Oxygen therapy is only recommended when patients are hypoxic (O2 saturation under about 93)
How can arrhythmia be managed pre-hospitally?
narrow complex tachycardias - standard or modified Valsalva - administration of adenosine - synchronised cardio version - electrocardioversion broad complex tachycardia - Amiodarone infusion - synchronised cardioversion bradycardia - atropine administration - adrenaline infusion - transthoracic pacing
what is the dosage of GTN used in ACS treatment?
300 micrograms every 5 minutes as needed, considering BP and having taken no PDE-5 inhibitors within 48hours (SAAS guidelines)
what are some risk factors for the development of ACS or other coronary diseases?
hypertension, smoking, high fat diet, high glucose levels, family history, being male, advancing age, hyperlipidaemia, cardiac history
what are the benefits of using fentanyl or morphine in the treatment of ACS?
- pain management
- reduction of anxiety
- decrease in sympathetic nervous system outflow
- reduced oxygen consumption
- can dilate coronary vasculature
