STEMI-27

Published: November 29th, 2015

Category: STEMI

Pre-hospital ECG:

IMG_3545

Emergency Department ECG:

A1

Ride-side ECG:

A2

Cardiac Cath Report:

LM– Large, no angiographic stenosis
LAD– Large, transapical, has luminal irregularities proximal and mid vessel, no angiographic stenosis
LCx– Normal caliber, no angiographic stenosis proximal vessel, distal vessel has 60% stenosis
RCA- 100% proximal occlusion (culprit vessel)

Teaching:

  • Right side MI
    • Complicates 40% of inferior MIs
    • Right ventricle is preload dependent which may lead to hypotension if Nitroglycerin is administered.  Treat with IV fluids and rapid transport.
  • Right side ECG
    • A complete set of right-sided leads is obtained by placing leads V1-6 in a mirror-image position on the right side of the chest (see diagram, below).
    • It may be simpler to leave V1 and V2 in their usual positions and just transfer leads V3-6 to the right side of the chest (i.e. V3R to V6R).
    • The most useful lead is V4R, which is obtained by placing the V4 electrode in the 5th right intercostal space in the midclavicular line. ST elevation in V4R has a sensitivity of 88%, specificity of 78% and diagnostic accuracy of 83% in the diagnosis of RV MI
  • Inferior MI
    • 40-50% of all myocardial infarctions.
    • more favorable prognosis than anterior myocardial infarction
    • Up to 40% of patients with an inferior STEMI will have a concomitant right ventricular infarction. These patients may develop severe hypotension in response to nitrates and generally have a worse prognosis.
      • Confirmed with Right sided ECG, Elevation in V4R
    • Up to 20% of patients with inferior STEMI will develop significant bradycardia due to second- or third-degree AV block. These patients have an increased in-hospital mortality (>20%).
  • ECG findings
    • ST elevation in leads II, III and aVF
    • Reciprocal ST depression in aVL (± lead I)
    • RCA (80%): Elevation in III > II, Reciprocal depression in I
    • LCx (20%): Elevation in III = II, No reciprocal depression in I

Right Side ECG:

right-ventricular-leads.gif

ECG-Anatomy-LITFL