Acute Coronary Syndrome without ST elevation

Acute Coronary Syndrome without ST elevation

1. NSTEMI

Other conditions that cause elevated troponin

• PE
• Myocarditis
• Pericarditis
• Arrhythmias
• Renal failure
• Partial occlusion of a major coronary vessel
• Usually dx on the basis of
  • A suggestive history
  • ↑troponin levels (see box for ddx)
  • ECG changes

ECG changes

• No ST elevation
• No Q waves
• ECG can be normal
• Other changes can be
  • ST depression
  • Hyperacute T wave (tall pointy T waves) – normally resolve by the time pt is seen in the hospital
  • T wave inversion – late sign. Indicates previous MI

Troponin testing

• Can be ‘traditional’ or ‘high sensitivity’ troponin test
• Traditional test
  • Positive or negative test
  • Serial tests performed over 6-8 hours
  • Any detected troponin results in a (+) test – therefore a dx of NSTEMI
• High sensitivity test
  • Based on the fact that 50% of the population has an undetectable level of troponin, 50% have a detectable level of troponin
  • APPROX normal range is <5ng/L – varies from hospital to hospital
  • This method does two troponin tests, 2 hours apart, within 3 hours of onset of chest pain
    • A (+) test is defined as an increase in troponin between the two tests

2. UNSTABLE ANGINA

• Only distinguishable from NSTEMI through troponin testing
• TIMI  Score is used to determine the likelihood of ischemic events or mortality in patients with unstable angina or non–ST-segment elevation myocardial infarction (NSTEMI) – >5 points denotes high risk.

3. TREATMENT – see topic 10-4