Acute Coronary Syndrome (ACS)

How many hours after an acute myocardial infarction does serum troponin level start to rise?

Typically 3-6 hours after the onset of myocardial damage

How many hours after an acute myocardial infarction does serum troponin level peak?

12-24 hours after myocardial damage

How many hours after an acute myocardial infarction does serum troponin level start to normalise?

7-14 days after myocardial damage

What region of the heart is affected in a posterior myocardial infarction?

Posterior wall of the left ventricle

Which artery is most commonly involved in a posterior myocardial infarction?

Posterior descending artery (PDA), usually a branch of the right coronary artery (RCA)

Why is posterior myocardial infarction challenging to diagnose on a standard 12-lead ECG?

Posterior wall is not directly visualized by standard leads - typical ST elevation may not be seen

What ECG changes suggest a posterior myocardial infarction?

ST depression and tall, broad R waves in leads V1–V3

What ECG leads can be added to confirm a posterior myocardial infarction?

Posterior leads V7, V8, and V9 placed over the scapular region

What changes are seen in posterior leads V7–V9 in a posterior myocardial infarction?

ST elevation

List the 3 conditions which the term acute coronary syndrome (ACS) encompasses

1) Unstable angina

2) Non-ST elevation myocardial infarction (NSTEMI)

3) ST elevation myocardial infarction (STEMI)

What are the 2 commonest risk factors for cardiovascular mortality?

1) Hypertension

2) Smoking

Provided there are no contraindications what the first-line emergency medication is given in ACS?

Aspirin 300 mg orally

What is the treatment of choice in patients with ACS who have ST elevation or left bundle branch block (LBBB) on their ECG?

Reperfusion therapy: primary percutaneous coronary intervention (PCI) or thrombolysis

In ST-elevation myocardial infarction (STEMI) what is the localisation of the infarct with changes in leads V1-V4/V5?

Anterior

In ST-elevation myocardial infarction (STEMI) what is the localisation of the infarct with changes in leads V1-V3?

Anteroseptal

In ST-elevation myocardial infarction (STEMI) what is the localisation of the infarct with changes in leads V1-V6, I and aVL?

Anterolateral

In ST-elevation myocardial infarction (STEMI) what is the localisation of the infarct with changes in leads V5-V6, I and aVL?

Lateral

In ST-elevation myocardial infarction (STEMI) what is the localisation of the infarct with changes in leads II, III, aVF and V5-V6 (and sometimes I and aVL)?

Inferolateral

In ST-elevation myocardial infarction (STEMI) what is the localisation of the infarct with changes in leads II, III and aVF?

Inferior

In ST-elevation myocardial infarction (STEMI) what is the localisation of the infarct with changes in leads II, III, aVF and V1-V3?

Inferoseptal

In a posterior myocardial infarction what abnormality is typically seen in leads V1-V2 on the ECG?

Tall R-waves

GTN use in angina relieves symptoms after approximately what period of time?

Few minutes

Which cardiac enzyme is the first to rise in an acute myocardial infarction?

Troponin

Following acute myocardial infarction during what time-period is ventricular fibrillation most likely occur?

80% of cases occur within 12 hours