Is it a blocked coronary?10 do-not-miss EKG patterns

Louis Mullie, PGY-4GIM / ICU program

Université de Montréal

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Disclosures• Chief technical officer, Pathway Medical Inc.

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Credits for EKGs• Dr. Smith’s ECG blog

http://hqmeded-ecg.blogspot.com/

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Objectives1. Recognize uncommon patterns of ischemia on EKG

2. Differentiate acute occlusion MI from non-occlusive ischemia

3. Recognize situations where ischemia can be missed on EKG

4. Recognize non-coronary mimics of ischemia on EKG

5. Understand and apply the principle of ST-axis, ST/T ratio, and Dr. Smith’s formula for ST elevation MI

Reminder: STEMI criteria• New J point elevation ≥ 0.1 mV in 2 contiguous leads• Except in V2-V3, where at least ≥ 0.15 mV is required*

• Measure from upper edge of PR segment (not T-P segment)

* 0.15 mV in females, 0.2 mV in men > 40 years, 0.25 mV in men < 40 years

Eur Heart J.2018Jan7;39(2):119-177.

Case #162M known for HTN, HFpEF. Presents with 5 days of gradual SOB and leg edema.

Answer: LVH with repolarization abnormalities

ST/S =3mm/50mm=6%

LVHST/S = 0.06

STEMIST/S = 0.14

Key points• Repolarization abnormalities due to LVH are a common cause

of “false-positive” cath lab activation for presumed STEMI

• Anterior ST elevation with convexity in leads V1-V3 in the presence of severe LVH does not necessarily mean STEMI

• In such cases, ST elevation / S wave depth ratio < 0.10 has high sensitivity to exclude STEMI as the cause of ST elevation

AmJCardiol.2012Oct 1;110(7):977-83.

Case #244F with no medical history. Presents with dyspnea and left shoulder pain.

Answer: pulmonary embolism

T wave inversionsinInferior leads(II,III)

T wave inversionsinRprecordial leads(V1-V4)

Key points• Differential diagnosis of de novo precordial T wave inversions

includes right heart strain in addition to coronary ischemia

• In the setting of atypical chest pain and dyspnea, PE is the more likely cause of new precordial T wave inversions

• Simultaneous inversion of T waves in precordial leads and lead III has >95% positive predictive value for predicting PE

AmJCardiol.2007Mar15;99(6):817-21.

Case #378M known for HTN, CVA, CKD (baseline Cr ~200). Presents with confusion, agitation.

Answer: De Winter’s T waves - anterior myocardial ischemia

Tall,symmetricTwaves

Answer: De Winter’s T waves - anterior myocardial ischemia

1mmupslopingSTdepressionattheJpoint

Bluntedpeak

Fatbase

Pointypeak

Narrowbase

De Winter’s Early repolHyperkalemia

SlowupstrokeFastdownstroke

JpointnotchingSTdepression

Key points• Differential diagnosis of ↑ T wave amplitude includes coronary

ischemia, benign early repolarization, and hyperkalemia

• De Winter’s T waves are broad-based, with a blunted peak, and often show associated upsloping ST depression

• The De Winter’s pattern has a >95% positive predictive value in predicting significant stenosis of a major epicardial vessel

Eur JEmerg Med.2017Aug;24(4):236-242.

Case #428M smoker. Presents with vague chest discomfort.

Answer: benign early repolarization

“Fishhook”patternatJpoint

ConcaveSTEV4

Key points• In patients with concave ST elevation without accompanying

ischemic changes, consider “benign” early repolarization

• LAD occlusion (vs. BER)• ST elevation is higher• QTc is higher• R wave is smaller

• BER in inferior leads associated with sudden death (RR 1.28)

JElectrocardiol.2017Sep - Oct;50(5):561-569.

Use Dr. Smiths rule to differentiate the two

mdcalc.com/subtle-anterior-stemi-calculator-4-variable

>90% sensitivity and specificity

NEngl JMed.2009Dec 24;361(26):2529-37.

Answer: benign early repolarization

Case #557M with Afib on OAC. Presents with 5 days of crescendo angina. Hb 48.

Answer: diffuse subendocardial ischemia

Key points• ST elevation in aVR has been considered a “STEMI equivalent,”

but this is controversial due to low specificity for ACS (~30%).

• ST elevation in aVR is more commonly due to reciprocal changes from diffuse subendocardial ischemia.

• A significant proportion of these patients have significant left main disease or multivessel disease and are at high risk

JIntern Med.2012Apr-Jun;50(2):159-64.

Case #644M known for DM2, obesity. Presents with 15 min crushing chest pain, now resolved.

Answer: Wellen’s pattern – transient LAD occlusion

BiphasicTwavesinV2-V4

Key points• Wellen’s syndrome is a pattern of deeply inverted T waves in

V2-V3 and is highly specific for a critical LAD stenosis

• Inverted T waves represent reperfusion of a transiently occluded LAD; patients may be pain free and cardiac enzymes may be normal at the time of presentation

• Normalization of T waves indicate re-occlusion of the LAD

JEmergTraumaShock.2009Sep;2(3):206-8.

Wellen’s pattern A25%

Wellen’s pattern B75%

BiphasicTwaves DeeplyinvertedTwaves

Case #754M with no PMHx. Presents with 3 hour history of crushing chest pain.

Answer: left circumflex artery occlusion

DeceptivelyreassuringEKG!

Key points• Left circumflex artery occlusions are an underdiagnosed clinical

entity and may be very subtle or invisible on EKG, leading to delayed PCI and increased morbidity

• Keep in mind the indications for PCI in “NSTE-ACS”• chest pain despite maximum medical therapy• severe LV dysfunction or heart failure• new MR or ventricular septal defect• new sustained ventricular arrhythmias

JAmColl Cardiol.2014Dec 23;64(24).

Case #832M with recent cocaine use. Presents with typical chest pain.

Case #832M with chronic cocaine use. Presents with typical chest pain.

FindtheendoftheQRSsegment

Answer: high lateral STEMI

1mmSTelevation

1mmSTelevation

Key points• Isolated lateral STEMI is caused by occlusion of branch

arteries supplying the lateral wall (D1, OM, ramus intermedius).

• High lateral STEMI shows isolated STE in leads I and aVL.

• ST elevation is not typically masked by RBBB - tracing the end of the QRS can assist in evaluating STE accurately

NAmJMedSci.2016Feb;8(2):121–122.

Case #962M known for HFrEF, severe AS, LBBB. Presents with worsening epigastric pain.

Answer: anterior STEMI

1mmSTdepression

Step 1: find concordant leads (ST deviation and QRS in same direction).

Step 2: in concordant leads, is there STE ≥ 1 mm OR STD ≥ 1 mm in V1-V3?

1mmSTdepression

Step 3: in the other (discordant) leads, is there an ST/S ratio > 0.25?https://rebelem.com/modified-sgarbossa-criteria-part-deux/

Key points• Diagnosis of STEMI in the face of LBBB is challenging - most

de novo LBBBs do not represent acute coronary occlusion

• Modified Sgarbossa criteria are more sensitive than the original criteria (80% vs. 56%) and should be used in their place

• In concordant leads: ≥ 1 mm of STE OR ≥ 1 mm STD in V1-V3• In discordant leads: excessive discordance (ST/S ratio ≥ 0.25)

AmHeart J.2015Dec;170(6):1255-64.

Case #1058M known for HTN, DLP, DM2. Awoke from sleep with L arm pain and diaphoresis.

Answer: posterior STEMI

STdepression

3mminV25mminV34mminV4

Answer: posterior MI

STelevation

0.5mminV8-V9

V7

V8

V9

What is the ST axis?

STdepression

3mminV25mminV34mminV4

Indian Heart J.2016Sep;68(Suppl 2):S15–S17.

ST axis is 180o from direction of ST depression.

STdepression

3mminV25mminV34mminV4

ST axis is posterior.

Indian Heart J.2016Sep;68(Suppl 2):S15–S17.

Key points• Isolated posterior STEMI may be seen in 3% of myocardial

infarctions, usually due to occlusion of the left circumflex artery.• Inferior ST elevation will be present only if the LCx is dominant.

• When seeing ST depression, ask “what is the ST axis?”

• If the ST axis is posterior, obtain posterior leads (V7-V8-9); 0.5 mm ST elevation in 2 of these leads is diagnostic of STEMI

PermJ.2015Fall;19(4):e143–e144.

Summary (1)• Are there hyperacute T waves?

• Is there visible ST elevation?• If RBBB à find the end of the QRS segment• If LBBB à apply modified Sgarbossa criteria

• Is there “invisible” ST elevation?• If anterior STD à posterior leads to r/o posterior STEMI• If refractory CP, CHF, etc. à cath to r/o LCx STEMI

Summary (2)• Are there T wave inversions?• Consider Wellen’s syndrome

• Is it a non-coronary mimic?• Anterior STEMI vs. BER à Smith’s formula• Anterior STEMI vs. LVH à consider ST/S ratio• Wellen’s vs. PE à look at inferior leads

• Serial ECGs, troponins, echocardiogram!

Thank you!