Acute Coronary Syndrome (ACS)

  Hi guys!

From previous post, the topic that we discuss is about chest discomfort. Based on the differentials acute coronary syndrome is one of it hence, what is ACS? 

In UA, myocardial injury is absent and cardiac biomarkers are normal.

In myocardial injury, cardiac biomarkers are raised.

It is important to distinguish between myocardial injury and myocardial infarction
(MI).

Myocardial Injury	Myocardial Infarction (MI)
Myocardial injury may be due to: • ischaemia and/or • non-ischaemic causes (eg myocarditis, renal failure)	MI is myocardial injury due to ischaemia. It is defined pathologically as myocardial cell death due to prolonged ischaemia.

MI is diagnosed when there is a rise and/or fall in cardiac troponins, with at least
one value above the 99th percentile of the URL, and accompanied with at least one
of the following:

     I.        Clinical history consistent with chest pain of ischaemic origin of > 30 minutes.
    II.        ECG changes of ischaemia/infarction and/or the development of pathological Q waves.
  III.        Imaging evidence of new loss of viable myocardium 

           or new regional wall motion abnormality.
  IV.        Identification of an intracoronary (IC) thrombus by angiography or autopsy.

MI may be STEMI or NSTE-ACS based on the ECG.

STEMI is diagnosed when there is:

• ST elevation of > 1 mm in 2 contiguous leads or

• a new onset LBBB in the resting ECG

more about LBBB - check out ->https://litfl.com/left-bundle-branch-block-lbbb-ecg-library/

• in a patient with ischaemic type chest pains of > 30 minutes and

• accompanied by a rise and fall in cardiac biomarkers.

In NSTE-ACS, ST elevation is absent on the resting ECG. In addition, patients having prolonged ischaemic type chest pain and having a non-interpretable resting ECG (eg paced rhythm, new RBBB etc) without ST elevation are having NSTE-ACS.

reference: CPG Management of Acute ST Elevation Myocardial Infarction (STEMI) (4^th ED) 2019; Malaysia

Pathogenesis: 

Acute coronary syndrome almost always occurs in patients who have atherosclerosis (already mention in previous post https://avisenaremarques.blogspot.com/2021/01/coronary-arterial-disease.html) .

credit 

https://www.thrombosisadviser.com/en/professionals/

reference: Haslett, C. (2018). Davidson’s Principles and Practise of Medicine. (23^rd Edition). London: Churchill Livingstone.

* vomiting is a symptom

Symptoms:

Signs:

Immediate investigation:

• ECG
• cardiac biomarkers
• - troponins
  
• - CK-MB

reference: CPG Management of Acute ST Elevation Myocardial Infarction (STEMI) (4^th ED) 2019; Malaysia

unable to imagine what is time to wire, this video can help you understand it clearly:

*might be a bit different to our country but most of it similar and the most important term here is 

TIME IS MUSCLE/MYOCARDIUM

credit: 

https://www.nhrmc.org/

credit: 

https://www.mercy.net/

For NSTE- ACS:

Pre-hospital Management

Based on the triage:
If the history is suggestive of ACS :

-Give soluble aspirin 300 mg crushed stat

- Give sublingual GTN

- Do 12 lead ECG and cardiac biomarkers

If the ECG and cardiac biomarkers are suggestive of ACS

- Give clopidogrel 300 mg stat if available.

- Send the patient to the nearest healthcare facility where definitive treatment can be given.

If the ECG and cardiac biomarkers are inconclusive for ACS

Low risk patients : they can be referred as outpatient for cardiac assessment. 

Intermediate / High Risk patients : should be admitted

REFERENCE: CPG MANAGEMENT OF UNSTABLE ANGINA/NON ST ELEVATION MYOCARDIAL INFARCTION (UA/NSTEMI) 2011; MALAYSIA