1. Myocardial Infarction and the ECG
MEHDI BAKHSHI
MSN
PhD
ICNS

2. Paul D. Sherry, M.D. Parkside Cardiology
Financial Disclosure
9/2/2010
neither I, nor any member of my immediate family, within the last 12 months, have had a financial relationship with any proprietary entity producing health care goods or services.

3. Myocardial Infarction and the ECG
Very brief ECG basics
Definition of ST elevation
Definition of a significant Q wave
Localizing the area involved in the MI
Some ECG cases
Pseudo infarcts

4. Definition of Acute M.I.
2007 Joint Task Force of the European Society of Cardiology, ACC, AHA
A clinical event consequent to the death of cardiac myocytes that is caused by ischemia

5. An acute MI can occur with a normal ECG
The most important tool early on in diagnosing an MI is still the history.
Diagnosis of an acute or old anterior MI with a LBBB can be difficult if not impossible
Remember the value of serial ECGs in acute coronary syndromes

6. The Three Bipolar Limb Leads

7. Precordial Leads and the location of V4R

10. Current of Injury Patterns

11. What is significant ST elevation?
Elevation of the origin of the ST segment at its junction (J point) with the QRS complex of ≥ 1 mm in two or more limb leads or precordial leads V4 to V6
Or ≥ 2 mm in two or more precordial leads V1 to V3

12. Current of Injury during balloon inflation in the left anterior coronary artery
Wagner, Galen: Marriott’s Practical Electrocardiography, 10th edition, page 176

13. What is the difference between a physiologic Q wave and one that indicates an infarction?

14. ECG time intervals

15. Physiologic Q waves are less than or equal to .02 sec
Except for lead III, AVR and V1, Q waves greater than or equal to 0.4 seconds are abnormal.

16. Myth Q waves always mean transmural infarct
Non Q wave infarcts always are subendocardial
Q waves tell you there has been an infarct
Q waves don’t tell you about pathology

17. Septal Q waves in the inferior and anterolateral leads
II, III, avf, V3-V6

18. Reciprocal Changes
The ECG recorded from one side of the electric field of the heart will be seen in an upside-down mirror image on the other

19. Reciprocal Changes

20. Localizing Infarcts on the 12 Lead ECG
Lateral - Cx
Ant – sep - LAD
Anterior - LAD
Lateral - Cx
Inferior - RCA
Lateral - Cx
Ant – sep - LAD
Anterior - LAD
Lateral - Cx
Inferior - RCA
Inferior - RCA