st segment – the thing you can’t miss

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

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ST Segment – The Thing You Can’t Miss. Nick Sparacino Cardiology Study Group. 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. - PowerPoint PPT Presentation

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Page 1: ST Segment – The Thing You Can’t Miss

ST Segment – The Thing You Can’t Miss

Nick SparacinoCardiology Study Group

Page 2: ST Segment – The Thing You Can’t Miss

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

Page 3: ST Segment – The Thing You Can’t Miss

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

Page 4: ST Segment – The Thing You Can’t Miss

Mechanism of ischemic/injurious ST Changes

• 2 “phases” of electrical activity • Ischemic tissue depolarizes and repolarizes

less vigorously than healthy tissue

Page 5: ST Segment – The Thing You Can’t Miss

How does that make the squiggly line change?

Page 6: ST Segment – The Thing You Can’t Miss

Location, Location, Location

Page 7: ST Segment – The Thing You Can’t Miss

Where’s the lesion?

Page 8: ST Segment – The Thing You Can’t Miss

Where’s the lesion?

Page 9: ST Segment – The Thing You Can’t Miss

Where is the lesion? What is your mgmt?

Page 10: ST Segment – The Thing You Can’t Miss

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!

Page 11: ST Segment – The Thing You Can’t Miss

Early Repolarization

Page 12: ST Segment – The Thing You Can’t Miss

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

Page 13: ST Segment – The Thing You Can’t Miss

Digoxin

• Derangements in Na/Ca movement produces changes in action potential

• Causes characteristic “scooped” inverted ST-T• Looks like check-mark

Page 14: ST Segment – The Thing You Can’t Miss

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!

Page 15: ST Segment – The Thing You Can’t Miss

Pericarditis

• Diffuse ST elevation• Look at PR interval!

Page 16: ST Segment – The Thing You Can’t Miss

What do you do?

Page 17: ST Segment – The Thing You Can’t Miss

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

Page 18: ST Segment – The Thing You Can’t Miss

Neurologic insult

• Most often described with strokes• Trauma, tumor, metabolic derangements

Page 19: ST Segment – The Thing You Can’t Miss

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!

Page 20: ST Segment – The Thing You Can’t Miss

Over to you, Mo

• www.goodsamcsg.wikispaces.com• [email protected]• Powerpoints, articles, calculators, Oh My!• EKG reference cards