STEMI-66

Published: May 23rd, 2016

Category: STEMI

Pre-hospital ECG

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Emergency Department ECG

ECG2

  • Concern due to symptoms and inferior ST elevation, but patient has pacer making diagnosis difficult
  • Bedside echo by Cardiology showed wall motion abnormality, sent to cath lab

Cardiac Cath Report

1. LMCA: Short, ostial 30% stenosis, gives rise to the LAD and LCX.

2. LAD: Large, transapical, mid-to-distal diffuse 70% with findings of a large ostial D1 hazy 98% stenosis.

3. LCX: Large, co-dominant, widely patent, large OMB1 is patent, left PDA is patent.

4. RCA: Normal caliber, co-dominant (small PDA). Proximal RCA with focal 85% stenosis, mid vessel 30%, distally patent into small right co-PDA.

Successful stent placement to LAD D1, returned to cath later in hospital stay for stent placement to RCA

 

Teaching

  • In patients with left bundle branch block (LBBB) or ventricular paced rhythm, infarct diagnosis based on the ECG is difficult.
  • The baseline ST segments and T waves tend to be shifted in a discordant direction (“appropriate discordance”), which can mask or mimic acute myocardial infarction.
  • However, serial ECGs may show dynamic ST segment changes during ischemia.
  • A new LBBB is always pathological and can be a sign of myocardial infarction.
  • Sgarbossa Criteria
    • Can help determine if pt with baseline LBBB is having an MI
    • Concordant ST elevation > 1mm in leads with a positive QRS complex (score 5)
    • Concordant ST depression > 1 mm in V1-V3 (score 3)
    • Excessively discordant ST elevation > 5 mm in leads with a negative QRS complex (score 2). This criterion is sensitive, but not specific for ischemia in LBBB. It is however associated with a worse prognosis, when present in LBBB during ischemia.
    • A total score of  ≥ 3 has a specificity of 90% for diagnosing myocardial infarction.
    • During right ventricular pacing the ECG also shows left bundle branch block and the above rules also apply for the diagnosis of myocardial infarction during pacing, however they are less specific.

Sgarbossa