Stemi equivalents

STEMI Equivalents
• Are those patients who do not present
with this classical ECG changes but have
acutely occluded coronary artery.
• They are often associated with poorer
outcome and worse prognosis.
• Benefit from timely intervention

STEMI Equivalents
The common STEMI equivalents are:
• 1- de Winter ST/T complex
• 2- Wellens syndromes
• 3- ST elevation in lead AVR
• 4- LBBB with Sgarbossa criteria
• 5- Isolated posterior MI
• 6-T Waves upright in V1

• About 10-15% of admitted unstable
angina patients
• MI occurs in about 75% within one week
• The NNT for urgent catheterization to
prevent an MI is only 2.
• Usually require invasive therapy, do
poorly with medical management.
+Wellens’ Syndrome

Diagnostic criteria-
1. Progressive symmetrical deep T wave
inversion or biphasic T waves in leads V2-
and V3
2. Little or no cardiac marker elevation
3. Discrete or no ST segment elevation
4. No loss of precordial R waves.
5. Pattern abnormal during chest-pain free
periods
Wellens’ Syndrome

Wellens’ SyndromeWellens’ Syndrome

ECG during and after chest pain
Type 2

Wellens’ Syndrome
Differential diagnosis
• Pulmonary embolism
• RBBB and RVH
• LVH
• HOCM
• Raised intracranial pressure
• Normal pediatric ECG
• Persistent juvenile T wave pattern
• Brugada syndrome
• Hypokalemia

De winter syndrome
• Is an anterior STEMI equivalent that
presents without obvious ST segment
elevation.
• Is a relatively uncommon ACS (about 2% of
acute LAD occlusions), but is very important
to recognize.
• This syndrome is under recognized by
clinicians, with consequent increased
morbidity and mortality.
De winter syndrome

De winter syndrome
Diagnostic criteria are:
● Upsloping ST segment depression ( > 1 mm) at
the J-point seen in V2-4
●Hyperacute T waves. The ascending limb of the T
wave commencing below the isoelectric baseline.
De winter Syndrome

De winter syndrome
• de Winter's waves are probably due to
severe subendocardial ischemia, with
some epicardial ischemia (enough to
result in hyperacute T-waves, but not
enough for ST elevation.

De winter syndromeDe winter syndrome

De winter syndrome
• In contrast to Wellen's syndrome patients
present with chest pain, making the
presentation even more acute.
• They should have urgent angiography,
(even more so than in the case of
Wellen’s syndrome, who may have
angiography within a day or so).
De winter syndrome

De winter syndrome
• If doubt exists about the nature of the
chest pain, an echocardiogram can
confirm anterior LV dyskinesia
De winter syndrome

aVR ST segment elevation and
widespread ST segment depression
• ST elevation in lead aVR, with or without
minor ST elevation in V1, with inferolateral ST
depression is an independent marker of acute
left main stem occlusion.
• The in-hospital mortality rates are very high
(83 to 94%) regardless of the method of
management

• Sometimes difficult to identify these patients,
because the predominant clinical symptom
may be catastrophic but not predominantly
chest pain
• They often present with:
pulmonary oedema, shock, arrhythmia or
respiratory failure requiring ventilatory support.

Diagnostic criteria:
•ST elevation in aVR ≥ 1mm
•ST elevation in aVR ≥ V1
•Widespread horizontal ST depression, most
prominent in leads I, II and V4-6

Pathophysiology:
• One theory suggests that there is basal
septal ischemia/infarction due to major
septal branch occlusion leading to aninjury
current directed towards the
right shoulder.
• Diffuse subendocardial ischemia producing
reciprocal changes in aVR

ST elevation in aVR is not entirely specific to
LMCA occlusion. It may also be seen with:
•Proximal (LAD) occlusion
•Severe multi-vessel disease
•Diffuse subendocardial ischaemia – e.g. due to
O2 supply/demand mismatch,

In the context of widespread ST depression +
symptoms of myocardial ischaemia:
•STE in aVR ≥ 1mm indicates proximal LAD / LMCA
occlusion or severe 3VD
•STE in aVR ≥ V1 differentiates LMCA from proximal
LAD occlusion
•STE in aVR ≥ 1mm predicts the need for CABG
•Absence of ST elevation in aVR almost entirely
excludes a significant LMCA lesion

Emergent PCI may decrease mortality to 40%

Implications for therapy in acute coronary
syndromes
• Patients with < 1mm STE in aVR may safely
receive clopidogrel/prasugrel as they are
unlikely to proceed to urgent CABG.
• Patients with ≥ 1 mm STE in aVR may
potentially require early CABG

Although only a minority of patients with AMI
have LBBB their mortality is often significantly
higher than that of other patients with AMI.
Acute chest pain with LBBB can manifest in any
of the following 3 ways:
I. Commonest - LBBB but no pre-existing ECG.
II. LBBB and previousECGs do not show LBBB.
III. LBBB and is known to have LBBB on old ECGs.
NEW LEFT BUNDLE BRANCH BLOCK

• New or presumably new LBBB has been
considered a STEMI equivalent until AHA
guidelines 2013
• New LBBB should not be considered
diagnostic of acute MI in isolation

You should consider emergent PCI for LBBB in 3
situations:
1) Unstable patient (hypotension, pulmonary
edema, electrical instability)
2) The Sgarbossa criteria satisfied ( score ≥ 3
points)
3) Smith Modified Sgarbossa Criteria Satisfied

5points 3points2points

Increased sensitivity from 20% to 90% and
decreased specificity from 98 to 90%

Isolated Posterior MI
• Acute LCX occlusion often presents with
isolated ST-depression ≥0.05 mV in leads
V1-V3 which corresponds to acute MI of the
infero-basal portion of the heart.
• Posterior chest wall leads [V7 –V9] is
recommended to detect ST elevation
consistent with infero-basal myocardial
infarction.

• 4-7% of STEMIs present as Isolated PMI.
• Inspite of the relatively small myocardial mass
necrosis the clinical consequences of PMIs are
often serious and disproportionate.
• In one study by Matetzky et al MR was
present in 69% of patients with isolated PMI
which was moderate or severe in one third of
them.
• This ECG finding should be treated as a STEMI.
Isolated Posterior MI

ACUTE CORONARY SYNDROME - T
WAVES UPRIGHT IN V1
• An upright T wave in V1 is considered an
abnormal finding.
Characteristics of upright T wave in V1,
which are especially significant include:
● Very Tall T waves in V1: defined as a
TV1>TV6".
● New upright T wave

The causes of an upright T wave in V1 include:
1. Occasional normal finding in the elderly.
2. Incorrect lead placement.
3. LBBB
4. LVH
5. High LV voltage in young people
6. A critical proximal stenosis within :
● LAD ●LMCA ● LCX ● RCA
WAVES UPRIGHT IN V1

The following is a series or 15 -20 minutely
ECGs of a 61 year old woman who
presented with ongoing chest pain:
WAVES UPRIGHT IN V1

WAVES UPRIGHT IN V1

• Subsequent ECGs showed definite ST
segment elevation and critical LAD stenosis
was detected and stented.
Management
• They should be treated as having a critical
proximal coronary artery stenosis till proven
otherwise.
WAVES UPRIGHT IN V1

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