STEMI Equivalents

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STEMI Equivalents

Hyperacute T Waves

  • in ≥ 2 contiguous leads

  • broad and asymmetric

  • concerning when upright T-wave in V1 > V6

  • also need to rule out hyperK

Wellen's Waves

  • Commonly in V/2/V3

  • Type A: biphasic T waves

  • Type B: more common; deep, symmetric T waves inversions

ekg2.png

AVR

  • ST Elevation >1mm in AVR and/or V1 with diffuse depressions

  • LMCA occlusion, LAD occlusion, or triple vessel disease

    • Nonspecific, can also see this EKG with PE, aortic dissection, etc.

ekg4.png


De Winter’s T Waves

  • ST depression with peaked T Waves

    • > 1 mm of upsloping ST depression and tall symmetric T-waves commonly in the precordial leads

  • Proximal LAD occlusion

ekg6.png

Also consider:


Posterior MI

  • ST depressions in V1-V3

  • Get posterior EKG with leads V7V8V9

    • STE ≥ 0.5 mm (≥ 1 mm in men < 40 years) in V7, V8, or V9

  • Left circumflex or RCA occlusion

Right Ventricular MI

  • should consider in your inferior STEMI pts

  • ST elevation in V1 (+/- V2 ST elevation OR depression)

  • ST elevation in lead III > lead II

  • Get a right sided EKG with leads V3V4V5

    • Can have elevations in these

  • RCA occlusion

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Irregular Rhythms

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EKG #1

What’s the rhythm?

afib.png

EKG #2

Dude, what’s the rhythm?

MAT.png

EKG #3

Home skillet, what’s the rhythm?

MAT.png

BONUS QUESTION: What is a Lewis Lead?

EKG #1 - Atrial Fibrillation

·      Super irregular! This is probably the most common irregularly irregular rhythm we see

·      You may have confused this with atrial flutter because of the coarse fib waves in V1

o   First, you’re not alone: 1999 study showed high frequency of incorrect diagnosis, even by cardiologists: https://www.ncbi.nlm.nih.gov/pubmed/10549907

o   It may not matter, since aflutter and afib are treated same way in the ED

 

But since you’re all nerds like me, here’s how to differentiate…

1.     The waves in atrial flutter are much more uniform than the ones above.

2.     Flutter waves are classically sawtooth morphology

3.     Remember atrial flutter can be regular. It is only irregular when you have variable conduction.

I.e. when you have two flutter waves and a QRS, then three flutter waves and a QRS, then four, then two again…

Screen Shot 2019-09-13 at 5.25.55 PM.png

EKG #2 - Multifocal Atrial Tachycardia (MAT)

·      Multiple foci in the atria triggering the AV node. Look at all the different P wave shapes!

·      Three separate P wave morphologies = diagnostic of MAT

·      The slow version of MAT is a wandering pacemaker (MAT without the T)

·      Classically presents in a patient with COPD or CHF

·      Note that this EKG has R axis deviation, perhaps from cor pulmonale

EKG #3 - Premature Atrial Contractions, Normal Sinus Rhythm

·      So this is yet another irregularly irregular EKG, and at first glance you may call this atrial fibrillation.

·      However, note all the well defined p waves – this is sinus tach

·      So why is it irregular?

·      Before those irregularly occurring QRS complexes, there is a p wave, and it looks exactly the same as all the other p waves (in height, width, and axis)

·      The SA node is firing early, depolarizing the ventricles, and creating an irregular rhythm

What is a Lewis Lead?

Ohmygod, great question, so glad you asked!

From Wikipedia: “A Lewis Lead is a modified ECG lead used to detect atrial [activity] when [it] is suspected… but is not definitively demonstrated on the standard 12 lead ECG.”

So you think someone has atrial flutter (sustained HR of 145 perhaps?) but you can’t see any p waves or sawtooth activity. 

Maybe you’re trying to discern SVT from fast sinus tach?

How can you solve this conundrum?

Lewis Lead!

1. You can do this on the monitor, you don’t need a 12lead2. Arrange the leads as seen here. (The green one can go anywhere, it’s just an electrical ground)3. Check for atrial activity

1. You can do this on the monitor, you don’t need a 12lead

2. Arrange the leads as seen here. (The green one can go anywhere, it’s just an electrical ground)

3. Check for atrial activity

Before the Lewis Lead… (where the p waves at?)

After the Lewis Lead! (Retrograde p waves, mostly upright at the end of the QRS. No p waves prior to the QRS. This is SVT.)

Tachydysrhythmia Algorithm

Tachydysrhythmia Algorithm

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Ventriculoperitoneal  Shunt (Complications)

Background

  • Placed in the management of hydrocephalus

    • Hydrocephalus can be secondary to many disease processes, some included below:

      • Congenital

      • Spina bifida

      • Tumors

      • Post-meningitic

      • Dandy walker syndrome

      • Arachnoid cysts

      • Idiopathic Intracranial HTN

  • Location of the shunt is based on the location of blockage causing the hydrocephalus

    • Ventricular catheter can be placed in any brain ventricle (lateral, third, fourth)

      1. Valve portion then connects to distal end of the catheter/tubing, which can terminate in tissue that has epithelial cells capable of absorbing incoming CSF

        1. Most commonly in the abdominal peritoneal space, but can also be placed in the heart (right atrium, VA shunt), pleural cavity, etc. (see below images)

  • Most common neurosurgical procedure to cause complications

  • shunt failure occurs in 14% of children in the first month, 50% in first year

Symptoms of Complications

  • Adults: nausea/vomiting, lethargy, AMS, ataxia, CN palsies, paralysis of upward gaze (“sunset eyes”), seizures

  • Children: nausea/vomiting, irritability, lethargy, change in behavior, seizures, bradycardia, apnea, bulging fontanelle, prominent scalp veins,

 

Under-shunting

  • Obstruction of shunt flow

  • Develop high ICP and then aforementioned symptoms

  • Can be caused by extra-luminal obstruction or intraluminal obstruction

  • Extra-luminal obstruction

    • disconnection, kinking or fracture of the shunt system

  • Intra-luminal obstruction

    • Blockage caused by blood or CNS/inflammatory cells secondary to infection or tumor

 

Over-shunting

  • Over-drainage of CSF

  • Develop intracranial hypotension aka low ICP

    • Siphoning effect of CSF fluid upon standing

    • Develop headache that’s relieved in recumbent position

  • Can lead to slit ventricles

    • Complete collapse of the ventricles

    • Most patients are asymptomatic

    • Few will develop Slit Ventricle Syndrome

      1. Pathophys not fully understood

  • Can cause subdural hematoma

    • Over-shuntingàbrain collapseà tearing of bridging veins

 

CSF Shunt Infection

  • Usually within 6 months of placement

  • Can have fever, but not mandatory

  • External Infection = subcutaneous tract around the shunt

    • Swelling, erythema, tenderness along area of shunt tubing

  • Internal Infection = shunt and CSF contained within the shunt

    • Symptoms above

  • Staph epidermidis (50%) > Staph aureus (20%) > gram-negative rods (15%) > Propionibacterium acnes

  • Require shunt tap, usually by neurosurgery . not LP!

  • AB = cephalasporin + vanc

 

Work up

  • Labs are not very helpful

    • Can get cbc, sed rate, blood cultures

  • CSF

    • Protein can be high

    • Glucose can be low

    • Cultures negative 40% of time

  • Shunt series

    • XRs along course of VP shunt

    • Useful to visualize fractures/disconnection/migration of tubing (see below images)

    • Compare to old series

vp5.png

    • Just because shunt series may show a disconnection doesn’t mean theres actually a malfunction.

      1. Shunt may still be draining csf through another tract

  • CT head (non-con)

    • Should be paired with shunt series to further asses for malfunction

      1. Should not obtain shunt series/CT alone, should always be paired with each other

  • MRI

    • Interestingly, shunt hardware difficult to evaluate on mri

  • VP shunt tap

    • Indications in chart below

    • Almost always done by neurosurgery

  • Medications

    • Symptomatic therapy (Zofran, pain control etc)

    • if suspect infxn, AB as stated above

    • Consult with neurosurgery about starting steroids/acetazolamide to reduce ICP

  • Dispo

    • If presentation/imaging concerning then admit for further neurosurgery follow up

https://wikem.org/wiki/Ventriculoperitoneal_shunt_problems

http://www.emdocs.net/complications-csf-shunts-ed-presentations-evaluation-management/

https://www.ncbi.nlm.nih.gov/books/NBK459351/


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