Acute Coronary Syndrome Flashcards
What is ACS?
Acute Coronary Syndrome
What are the symptoms of ACS?
Chest pain.
SOB.
How does stable angina differ from unstable angina?
In stable angina, the chest pain should go away with rest.
In unstable angina, the chest pain will not go away without rest and continues for over 20minutes.
True or False: Angina is associated with elevated Troponin levels.
False - Troponin is an indication of cardiac tissue death which doesn’t occur in Angina.
True or False: Angina can not be seen on a 12-Lead ECG
True - There are no significant ECG changes seen in Angina.
What is a Myocardial Infaction (MI)?
An MI is irreversible isceamia of the cardiac tissue caused by lack of oxygen.
Describe how atherosclerosis can manifest into an MI if left untreated.
1) The coronary arteries are susceptible to the build up of Atheroma (fatty plaques).
2) In the early stages of atheroma build up the plaque begins to occlude the coronary artery (Stable Angina).
3) As the plaque hardens, it becomes harder for the artery to compesate when needed (Unstable angina).
4) If the hardened plaque breaks off, platelets surrounding the inside of vessel begin to create a thrombus (clot). If blood can flow around this thrombus then it would present as an NSTEMI - perfusion is inadequate but not completely blocked.
5) Further build of the thrombus leads to a completely occluded artery which is called a STEMI.
Which of the following conditions are associated with elevated Troponin?
Stable Angina
Unstable Angina
Non-ST Elevated MI
ST Elevated MI
NSTEMI + STEMI
Troponin is a protein that indicates cardiac tissue death, so it is only present when there is a lack of oxygen to the cardiac tissue causing ischaemia.
What is the difference between a NSTEMI and a STEMI?
An NSTEMI is a partially occluded coronary artery, there is still ischaemia but not bad enough to cause ST elevation on the ECG.
A STEMI is a full occlusion of the coronary artery, this results in significant ischaemia and ST elevation on the ECG.
What is the difference between a thrombus and an embolus?
A thrombus is a static clot.
If a part of that clot breaks off into the circulatory system it is called an embolus.
How is cardiac output calculated?
CO = SV x HR
Cardiac output = Stroke Volume x Heart Rate.
What is meant by stroke volume?
Stroke volume is the amount of blood ejected from the left ventricle into the aorta with each contraction of the heart.
Describe the physiology behind chest pain in ACS.
Increased oxygen demand caused by the plaque/thrombus forces the heart muscle to shift to anearobic respiration.
Byproducts of anaerobic respiration are lactate and hyrdogen.
The build up lactate triggers to nociceptors which send a signal of pain to the brain.
Describe the three components that make up or affect stroke volume.
Preload - How much blood fills the left ventricle.
Afterload - The pressure within the aorta that the left ventricle has to push against to eject the blood.
Contractility - The strength of the left ventricle squeezing.
With regards to contractility, what is Frank-Starlings law?
The force of contraction is proportional to the initial muscle fibre length.
i.e. the weaker the muscle the weaker the contractility.
Betty suffered some central stabbing chest pain that came on during her weekly jazzercise class at 9am.
She felt sick at the time and went home to rest, thinking to mention it at her GP nurse appointment later that afternoon.
At the appointment she still has the chest pain, complaining that her left arm is also quite painful, but not as bad as her chest which has become an aching pain.
Complete a full assessment of Betty’s pain using SOCRATES.
SOCRATES
Site: Central chest pain
Onset: Initially during exercise, but on-going at rest.
Characteristics: Stabbing and aching.
Radiation: Left Arm.
Associated Symptoms: Nausea
Timing: Several hours
Exacerbating or relieving factors: Nil
Severity: Moderate to high pain.
Billy has attended his GP for a health check-up after suffering some bouts of chest pain while working on his farm.
He explains that the pain normally subsides after a few minutes rest.
His observations are unremarkable apart from a slightly elevated BP (140/85).
He takes no regular medications.
He is a non-smoker.
He drinks 2-3 cans of lager each evening.
His bloods taken at his initial appointment last week show a Troponin level of 3.
His 12-Lead ECG shows no significant changes.
Based on the information above, which condition do you suspect Billy might have and why?
Billy likely has stable angina due to the chest pain symptoms going away after resting.
The insignificant ECG and low Troponin levels rule out any myocardial infarction.
A patient in the Emergency Department is identified as having ST elevation on their 12-lead ECG.
Should the patient be given supplemental oxygen?
No - current evidence shows that giving oxygen is contra-indicated during MI.
Identify 3 elements of a nursing assessment that should be completed on a patient with chest pain.
Baseline observations (NEWS2)
12-Lead ECG
Pain assessment (SOCRATES)
Bloods - Troponin
Past Medical History (PMH)
Patient Risk Factors
Assess family history
Multiple or “serial” troponins must be taken in the assessment of a patient with chest pain. Why?
A patient might have on-going cardiac issues or previous MI. Taking a second Troponin a few hours after the first one allows us to see if and how fast the troponin is increasing.
A GRACE Score divides patient into high risk (>3%) and low risk (<3%) of what?
Low or high risk of 6 month mortality and risk of further cardiovascular event.
