Smiths Modification and Pacemakers – is that a STEMI?

Ghu-roos. Prehospital diagnosticians. Call yourselves what you will.

We are here today to look through the pacemaker.
Like Alice through the looking glass; through to find any ischemia that potentially lurks within that paced rhythm. Don’t let that grey hair tell you about the futility of interpreting paced rhythms….just like they said with LBBB…..mmmm
So what can we do…

Example. 85 yr old caucasian male pt who initiates 911 after being unable to mitigate his chest pain with rest &/or nitrates as per usual. Today pt. pre administers nitrates prior to his daily walk as he knows he “will get chest pain to walk the small rise out of his home to gain the flats“. Pt. has an extensive cardiac history with quintuple bypass surgery a decade previous and just last year further stenting although he is not sure which artery. He presents to you with 6 on 10 central chest pain that will not resolve and feels like both pressure and burning. No radiation. No mitigation and very familiar in its presentation to his regular and frequent cardiac chest pain. No other associated symptomology. HR60 RR14 BP129/71 SPO297RA ETCO238mmHg BGL5.8 The pt. is taking all their medications as scheduled and no recent changes to Rx other than the addition of Plavix post angiography/stenting.

Your partner hands you the initial 12 lead that reveals the following…Applying Smith Modified Sgarbossa criteria provides you with the following;

  • V2 = T4.36/ST10 = 0.43
  • V3 = T6.54/ST12 =  0.54
  • V4 = T3.58/ST9 = 0.39










According to Smith Modified Criteria any T/ST variance >0.25 = both sensitive and specific for acute MI/STEMI.



Conundrum…you are closest to a non PCI capable Level 1 receiving facility and have access to a PCI facility although via diversion criteria is for STEMI only. Your organization does not support Paramedic’s interpreting their own 12 lead ECG and ECG must say STEMI  as interpreted by the LP15 algorithm for inclusion, transmission and thus diversion….what to do….

As you have a relationship with the ERP at your closest facility you reach out to them by phone and you are lucky enough to be able to have a clinical conversation with the receiving ERP. They agree with your treatment plan and ask you to divert to the PCI capable facility. You also consult with your online medical physician (EPOS) available to you who also agrees. You now transport your pt. to a cath/PCI capable facility and is accepted by cardiology upon arrival.

Learning points:

1. Use the modified Sgarbossa criteria in paced rhythms.  The specificity is good. The sensitivity is unknown but probably similar to sensitivity in LBBB, which I believe to be as good as ST elevation in normal conduction, probably about 70-75% sensitive for coronary occlusion (though the sensitivity was much higher in our case control studies, which probably do not accurately reflect clinical practice).

2. One difference between LBBB and Paced rhythm is that, in paced rhythm, the QRS in V5 and V6 is almost always negative (but positive in LBBB).  Therefore, any STEMI that manifests in V5 and V6 in LBBB will usually manifest by concordant ST elevation in these leads, whereas in paced rhythm, it must be excessively discordant ST elevation.

AVL ….predictor of the future

Can you look ahead. Can you see the future. Can you harness the Force appropriately. No. Neither can I; even despite being an Aquarius.

So what can I do to help me. Crystal ball you say?


AVL…..the crystal ball of EKG.

Mattu would refer to it as the Dangerfield lead…cant get no respect. Dr Henry J. Marriott identified this correlation 40 years ago but has seemingly escaped being included in our collectively perpetuating repertoire as pre hospital magicians.

More importantly than seeing into the future, is what you can see in the future. Prediction of evolving MI you say…whoa. Tell me more

Just say you went in an tied off the right coronary artery, for fun (type III fun), what would change first…thats right…AVL;
T wave inversion would occur.

Deviance from an almost-to flat T wave into a easily discernible flipped/inverted belly like T wave in AVL. You might even see some ST depression.
But what about LBBB… means nothing. Strain pattern? =both changes in AVL and Lead I. Horizontal heart…dont matter

OK, enough from us. Whet your appetite? Hope so.   Ill let Master Mattu take it from here.

In summary, experiencing chest pain….atypical findings, no baseline ECG to compare…no significant ischemic changes on 12 lead investigation….look to AVL…look to the future…advocate for those people you serve, repeat the ECG, consider the appropriate cath capable facility and at the very least have the discussion with your ERP.

Thanks for reading. Go well. AVL.

720…can you stick it?


Here at rightseatmedicine we are excited for the Toronto Paramedic Services and the Sunnybrook Centre for Prehospital Medicine who recently published a case report (Prehospital Emergency Care) exemplifying Double Sequential External Defibrillation (DSED) as a viable option for the prehospital conversion of refractory VF.


See the video illustrating the simulated application of such an intervention.

Exciting enough, DSED is also being supported here at Coastal Health and I have the opportunity to observe the resuscitation team here at LGH on the North Shore apply DSED to a patient under their care.

720. Can you stick it? Would it stick in your Service. Lets see how it shapes up here.




KINGVISION (videolaryngoscope) – tips & tricks

A newish tool for us here in the prehospital world, video laryngoscopy (VL), brought to us here in BC via the King Vision (KV) device.kv

But why use VL? As many of the old guard often remind me… ‘just learn to #$%^ intubate (DL) and you won’t need that fancy new thang” …Sigh… after seeing many patents brought emergently into the ED without airways protected due to repeatedly failed DL attempts, yet the VL remains in its packaging…..well…… we can’t emphasize enough the value-added-ness of this new tool to your airway intervention repertoire.

old-cartoon-medicWe hope to introduce some of the benefits of this new tool, some challenges we have encountered with prehospital intubations (n=18 …1 today) here at RSM using the King Vision… & just maybe… there’s something in here for the old skool-ers.

As with all new tools comes new decision making models and metrics for analysis, king-vision-flathowever we will speak to the technical applicational challenges we have encountered. One key early challenge we faced with the KV was the resistance to lay the device flat onto the chest when placing the blade into the mouth. It was counterintuitive to lose your view of the screen at such an early phase of the airway manoeuvre (where traditionally one would be highly anticipating any view during DL). However, once you expected it (loss of camera view), one could redirect their attention to blade placement in the mouth, displacement of the tongue and then refocus ones attention back to the screen. Once the airway structures come into view remember you are flying a plane (back stick = up view), too commonly practitioners want to lift the handle as one would during traditional DL (leading to occlusion / worse optics). Subtle backwards tilt of the handle will change view as does left and right angle of the wrist. Subtle.

kingvisionbladesSecondly was the choice of channeled/non channeled blades. Initially ETT #7 and larger were difficult (almost impossible) to free (dry plastic on dry plastic = stuck) from the channeled blade had you not pre lubed the exterior of the ETT, so we switched to non channeled blades. However we found it difficult to direct a bougie through the cords without the aid of directional feed/bend from the channeled blade. We abandoned this approach.

Another challenge was that we experienced significant hang up of the ETT bevel on the arytenoids. Solved only by full twisting the tube 180 degrees after being freed from the channelled blade. This rotation allows the bevel to roll anteriorly and pass through the undamaged cords into the trachea. All other methods seemed to inflict some level of trauma to the arytenoid structure. More on this shortly.

Our solution that has brought is the most success (n=12 1st pass success), lightly lubed & pre tied ETT with bougie not loaded into a channeled blade.

Procedure. Introduce KingVision to airway and obtain best view. Feed bougie along channel. Pass bougie through cords. Slip bougie out of channel, leave KingVision in situ for best view. ‘Railroad’ tube of choice (<#8) into view along bougie. Roll rotate ETT 180 degrees to allow bevel to free from posterior airway structures into trachea without force nor damage to arytenoids. Secure ETT as per recommended approaches.
This combination allowed us the most successful parameters. Stacking all the odds in our favour, bougie to pass through cords, then a visualized roll advancement of the ETT into place using ETT markers for airway depth.

So what about soiled or fluid airway you say….well….we found that there is a coating on the screen of the blades that clears somewhat independently once it has been dunked in airway secretions/vomitus…and that with a little assistance from the yankauer tip suction whilst still in the airway, the screen regained its clarity. The inherent heat from the bulb quickly clears residual fogging. And recent adaptations of suction hose into channelled blade during advancement has brought excellent success to the heavily soiled airway…(more to follow)…

Another exceptional piece with using the King Vision is from the educational perspective. Now the new user can be coached through the visualization and airway capturing process in the pre hospital environment. Others practitioners can simultaneouly follow along with the airway manoeuvre from a distance and augment their own understanding of the process and procedure. As demonstrated here with the King Vision & Bougie pass to capture an airway in the spontaneously respirating pt.

King Vision Bougie pass from tyson lehmann on Vimeo.

Another great external review of the KingVision from the folks at EMCRIT can be found here.

Accidental Hypothermia – new and exciting from Dr Doug Brown

Dr Doug Brown has recently published in the NEJM and addresses the prehospital management of Accidental Hypothermia and how it relates to those who also practice in the backcountry.

Dr Doug Brown’s website linking to his research and paper published in the NEJM.

Thanks Dr Brown, we appreciate your work and the support of those practicing outside.

Takotsubo… is not a Japanese Motorcycle

Broken Heart Syndrome, stress induced cardiomyopathy, left ventricular wall ballooning, that resembles a traditional Japanese ceramic octopus trap…TakJapanese_Superhero_on_Motorcycle_Posters_at_AllPosters_comotsubo; all of these yes. Japanese motorcycle…unfortunately not.

Often spoken about it like the mythical unicorn, rarely do we have the opportunity to discover one in our daily clinical investigation. This month at Right Seat Medicine, the Erin Baker brings to us a presentation of Takotsubo (Stress) Cardiomyopathy.

Broken Heart Syndrome, otherwise known as apical ballooning syndrome, which is characterized by transient systolic dysfunction of midtakotsubo_-_Google_Search segment or apex of the left ventricle, can mimic an acute myocardial infarction, without the presence of obstructive coronary artery disease.

The pathogenesis is not well understood, but is often triggered by medical illness or emotional stress.

 So what does it look like when you actually find one of these patients. Invariably most are post menopausal females who have suffered some variance of emotional distress and present with atypical or vague histories of malaise or discomfort. Not typically the population we would always perform a 12 lead echocardiogram upon, but todays case will again highlight the (differential and) diagnostic value of the 12 lead ECG.

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Jiro Dreams of Sushi…an ember for the prehospital Shokunin

Jiro dreams of sushi, and in doing so finds us the essence of what it is… to be our best.

This month at rightseatmedicine we take a journey with Jiro Ono, and perhaps,  a glimpse of what it is like to be a master. Like Yoda, but real. And how we can be better at what we do and most importantly, how we view ourselves amidst our craft.

The concept of repetition, forward vision, the pursuit of mastery; all based on a foundation of humility, hard work, self reflection and a relentless dedication to task, as Jiro suggests, a ‘yearning to achieve more’.

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Exercise Associated Hyponatremia – stop the NS

Unable to put a finger on, or differentiate your young healthy patients first time seizure activity? The absence of trauma, infection, stroke, any pertinent historical findings,thCAIST0VW heat/altitude illness or other pharmacological based explanation leading you toward a primary diagnosis of neoplasm or some other insidious intracranial nasty?

As the summer and warmer months are upon us, the consideration of Exercise Associated Hyponatremia (EAH) is warranted in these individuals.

Wilderness Medical Society Practice Guidelines for the Ttreatment of Exercise Associated Hyponatremia are representative of “…the great strides that are taking place in an effort to prevent what is now recognized as a leading cause of preventable mobidity and mortality in endurance activities throughout the world“.

How does this affect me as a pre hospital practioner you ask? We here at rightseatmedicine have encountered a small cohort of patients in the Lower Mainland region of BC presenting with exercise associated hyponatremia.

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Spinal Immobilization & ice cream – why cant we stop ourselves

A bowl of ice-cream…spinal immobilizing our patients…why can we not stop ourselves; and often our partners, from indulging.images

In light of the recent avalanche of discussion surrounding spinal immobilization in the prehospital environment, presented within this post you will find;

  • the original JEMS article that piqued our interest here at rightseatmedicine,
  • the new and exciting publication by the Wilderness Medical Society for Spine Immobilization in Austere Environments,
  • a video-link courtesy of Gallatin County who have recently adopted an adjusted spine immobilization protocol, and
  • numerous other immobilizing menu items that are delicious food for thought.

Please enjoy.

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