Introduction

Definition

• Acute Coronary Syndrome (ACS) is a clinical spectrum of Coronary Artery Disease (CAD) ranging from Unstable Angina (UA), non-ST segment Elevation Myocardial Infarction (NSTEMI) to STEMI depending upon the degree and acuteness of coronary occlusion.

  

• Myocardial infarct (MI) is myocardial injury due to ischemia.

• MI is defined pathologically as myocardial cell death due to prolonged ischaemia.

• Myocardial injury can be due to ischemia or non-ischemic causes (e.g myocarditis, renal failure).

Epidemiology

• Most deaths in STEMI occur within the first hour due to fatal arrhythmias.
• Most STEMI patients are young with a mean age of 58.6 years.
• Majority of men presented with STEMI (50.5%) whereas women presented with Non ST Elevation Acute Coronary syndrome (NSTE-ACS) (70.8%).
• The STEMI patients were generally more ill.
  • 67.4% were in the intermediate-high TIMI risk score.
  • 19.0% were in Killip class III/IV.
• 69.1% of patients received fibrinolytic therapy while 13.7% were treated with primary PCI. 14% of patients did not receive any form of reperfusion treatment due to late presentation, missed and delayed diagnosis.

Clinical Classification of MI

• Type 1: Spontaneous MI
• Type 2: MI secondary to an ischaemic imbalance
• Type 3: MI resulting in death when biomarker values are unavailable
• Type 4a: MI related to PCI
• Type 4b: MI related to stent thrombosis
• Type 5: MI related to coronary artery bypass surgery (CABG)

Diagnosis

Criteria

• 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:
  • Clinical history consistent with chest pain of ischaemic origin of > 30 minutes.
  • ECG changes of ischaemia/infarction and/or the development of pathological Q waves.
  • Imaging evidence of new loss of viable myocardium or new regional wall motion abnormality.
  • Identification of an intracoronary (IC) thrombus by angiography or autopsy.
• STEMI is diagnosed when there is:
  • ST elevation of > 1 mm in 2 contiguous leads or
  • a new onset LBBB in the resting ECG
  • in a patient with ischaemic type chest pains of > 30 minutes and
  • accompanied by a rise and fall in cardiac biomarkers.