This document provides an overview of various electrocardiogram (ECG) findings that can indicate acute myocardial infarction (AMI) or critical stenosis requiring intervention. It discusses ECG patterns seen in posterior MIs, left main coronary artery occlusions, De Winter's T waves, Wellen's syndrome, and Sgarbossa's criteria. Assessment of left ventricular ejection fraction is also reviewed, including fractional shortening, Simpson's method, and E-point septal separation. Limitations of certain methods in specific conditions are noted.

1. Morning Educational Activity
Rashid A. M. Abuelhassan
R3, Emergency Medicine

3. De Winter’s T Waves
Suggestive of proximal LAD lesion
12-Lead ECG findings[5]
Precordial ST-segment depression at the J-point
Tall, peaked, symmetric T waves in the precordial leads
Lead aVR shows slight ST-segment elevation in most cases

5. Posterior MI
RCA (90%), LCA (10%)
12-Lead ECG findings[2]
ST-segment depression (horizontal >> downsloping/upsloping)
Prominent and broad R wave (>30ms)
Relative tall R waves in precordial leads (may find R = S amplitude in V1)[3]
R/S wave ratio >1.0 in lead V2
Prominent, upright T wave
Combination of horizontal ST-segment depression with upright T wave
Posterior ECG or 15-lead ECG may be helpful
V7: Left posterior axillary line along the 5th ICS
V8: Tip of the left scapula line along the 5th ICS
V9: Left paraspinal area line along the 5th ICS
Posterior ECG findings
≥1 mm ST-segment elevation

7. LMCA Occlusion
Seen with occlusion or near-occlusion of the left main artery[4]
Has been reported in occlusion of the proximal left anterior descending
artery and severe multivessel coronary artery disease
12-Lead ECG findings
ST elevation in aVR ≥ 1mm
ST elevation in aVR ≥ V1
ST depression typically seen in lateral

10. Wellens’ Syndrome
Represents critical stenosis of the LAD
Not necessarily STEMI equivalent but will require PCI in the next 24-48hr
12-Lead ECG findings[8]
Deeply-inverted or biphasic T waves in V2-3
Isoelectric or minimally-elevated ST segment (<1 mm)
Absent precordial Q waves with preserved R waves
Two T wave characteristics:
Type A: Biphasic pattern - 25% - Biphasic T-waves (initial + deflection and terminal - deflection)
Type B: Inversion pattern - 75% - Deeply inverted and symmetric T-waves

12. Sgarbossa's Criteria
Original Criteria[6]
≥3 points = 98% probability of STEMI
ST elevation ≥1 mm in a lead with upward (concordant) QRS complex - 5 points
ST depression ≥1 mm in lead V1, V2, or V3 - 3 points
ST elevation ≥5 mm in a lead with downward (discordant) QRS complex - 2 points
Smith's modification[7]
Changes the 3rd rule of original Sgarbossa's Criteria to be ST depression OR elevation
discordant w/ the QRS complex and w/ a magnitude of at least 25% of the QRS increases Sn
from 52% to 91% at the expense of reducing Sp from 98% to 90%

13. STEMI equivalents
• Posterior MI
• LMCA Occlusion
• De Winter’s T Waves
• Sgarbossa's Criteria
• Wellens’ Syndrome

14. Assessing the Ejection Fraction
• Fractional shortening (FS)
= (LVEDD-LVESD/LVEDD)100 (25%-45%)
• Simpson’s Method
(Method of Discs)
• E-point septal separation (EPSS)

15. • inaccurate in
• mitral stenosis
• Calcification
• significant aortic insufficiency
• dilation of the mitral annulus from
dilated cardiomyopathy

16. Steps
• parasternal long axis window

17. • If the MV is touching the septum
 55%.
• Not  distance from MV during
the E-point and the septum
• A distance <0.7cm is normal EF.
• A distance >1.0cm is consistent with
a reduced ejection fraction.
• LVEF = 75.5 − 2.5 × EPSS

19. Thank you