1. ST Segment – The Thing You Can’t Miss
Nick Sparacino
Cardiology Study Group

2. ST Segment J-Point to beginning of T wave
Isoelectric in limb leads in 75% of “normal” EKG
Up to 90% of all EKG’s have some ST elevation precordially
>1mm elevation abnormal
Any depression abnormal

3. Baseline? I don’t need no stinking baseline!
Three potentially isoelectric portions
PR, ST, TP
PR can be unreliable, particularly if pericarditis is on differential
Generally use TP
None can be completely relied on with standard EKG

4. Mechanism of ischemic/injurious ST Changes
2 “phases” of electrical activity
Ischemic tissue depolarizes and repolarizes less vigorously than healthy tissue

5. How does that make the squiggly line change?

6. Location, Location, Location

7. Where’s the lesion?

8. Where’s the lesion?

9. Where is the lesion? What is your mgmt?

10. Early Repolarization Traditionally considered benign
1-5% of general population
More common with young males, African Americans
Large T waves, concave ST contour, no other evidence of LVH or other causes
Mimics hyperkalemia
2008 NEJM found 2.1 HR for SCD!

11. Early Repolarization

12. LVH Covered in last installment
High points: Estes-Romhilt is best criteria
Look for big QRS, negative P in V1, clinical history of htn, stim abuse

13. Digoxin
Derangements in Na/Ca movement produces changes in action potential
Causes characteristic “scooped” inverted ST-T
Looks like check-mark

14. Wellen’s Sign
1996 Wellen described a series of acute proximal LAD lesions with no ST elevation or troponin rise
Biphasic anterior T waves the only unifying feature
A case was missed by one of us at the VA recently – can’t lean on trops!

15. Pericarditis
Diffuse ST elevation
Look at PR interval!

16. What do you do?

17. Brugada
Most well known of a series of inherited ion channel pathologies
Produce a characteristic pattern of precordial ST elevation
3 described types, type 1 is the classic
Very high J point, smoothly descends to an inverted T
High risk of sudden cardiac death
Most common in southeast Asian males – up to .5-1% in a Japanese study

18. Neurologic insult Most often described with strokes
Trauma, tumor, metabolic derangements

19. When in doubt Call for help!
Fellow residents, senior residents, chiefs, fellows, IM attendings, cards attendings
“Better to wake someone up than put someone to sleep”
Practice!

20. Over to you, Mo www.goodsamcsg.wikispaces.com Cardiostudy@gmail.com
Powerpoints, articles, calculators, Oh My!
EKG reference cards