Monday, June 24, 2013

The FOAM Forecast - Better Than The Weather Guy/Gal

The Gist:  Old news in the Free Open Access Medical Education (FOAM) world often predates alterations in guidelines and bedside practice.  Thus, while we may regurgitate things solely for test taking purposes or to sate the local practice patterns, it may behoove us to acquaint ourselves with changing schools of thoughts prior to these changes trickling down in standard ways.  FOAM can serve as a means of preconditioning one's way of thinking and actions to mitigate the knowledge translation window.

The example: I recently completed my second iteration of ACLS testing with the 2010 guidelines and I encountered the following:
LBBB is a STEMI equivalent?  I was told this by an attending as a third year medical student but, through Twitter, I recalled recently noting that the 2013 AHA Guidelines state that new or presumed new LBBB, in isolation, is not an indication for a patient to proceed directly to PCI or thrombolysis (I.e. no other concerning features on ECG or sick patient status).   As I marked up my algorithm, wandering whether this distinction had clinically relevance, I recalled the following case from nearly a year prior...

The Case:  A 48 year old obese male presented to the Janus General ED with some new chest pain and mild dyspnea at 0300.  His vital signs were within normal limits and he appeared uncomfortable and anxious but in no distress.  A 12-lead ECG demonstrated a LBBB that failed to meet any of the Sgarbossa criteria.  My supervising physician instructed me to page the cardiology fellow to see the patient and push for PCI after my database search failed to produce an old ECG to look for a prior LBBB.  The cardiology fellow came in and, after seeing the ECG and the patient, stated he would take him to PCI later, perhaps the following day.  The patient had no bump in troponin and ultimately left the hospital without a diagnosis of an MI.
  • Interestingly just one week prior, I watched this brief tutorial from Dr. Amal Mattu on LBBB and MI, one of several times I'd heard this same trope on podcasts.  I followed the directives and waited until after shift to check into LBBB and MI a little further, knowing I shouldn't blindly accept something I watched on the internet.
How FOAM forecasted the guidelines and provided updated education: 
  • 2011an EMCrit episode featured a discussion with Dr. Stephen Smith regarding reading STEMI on  ECGs with an LBBB, introducing the ST/S ratio 
    • A ratio of the amplitude of the ST segment to the S wave >-0.25 is suggestive of ischemia/STEMI and increases the sensitivity of the Sgarbossa criteria (full text article), awaiting further validation 
  • July 2012: Dr. Mattu foretold the changing guidelines in 20 minute video on LBBB and MI.
  • December 2012:  EMS 12-lead Blog educates EMS providers on the removal of LBBB as a STEMI equivalent in the 2013 AHA guidelines
  • June 2013: Dr. Mattu's ECG tutorial of the week re-emphasized the ability to read MI on an ECG with a LBBB.   
These created a reading list on LBBB and MI - reinforcing life-long learning skills of reading:
  • Kontos et al
    • n=401 patients with LBBB undergoing AMI rule out
    • No difference in incidence of MIs between chronic and new LBBB
    • Concordant ST changes (n=14) were the most important predictor of AMI (OR 17, 95% CI 3.4-81, P < .001
    Chang et al
    • Observational cohort of ED patients with ACS symptoms
    • No difference in the rate of AMI between the 3 groups: 
      • new or presumed new LBBB - 7.3% (RR 1.1; 95% CI, 0.47-2.84)
      • old LBBB - 5.2% (RR, 0.84; 95% CI, 0.41-1.69)
      • no LBBB -6.1% 
    Jain et al
    • Retrospective single-center analysis. N =36 patients with new/presumed new LBBB and ACS symptoms (~1-2% of AMI population in this system), 12 diagnosed with AMI
    • 30/36 underwent emergent cath
    • Sgarbossa criteria performed poorly in terms of sensitivity (Score of at least 5, sensitivity ~14%)
    Neeland et al - Excellent review of LBBBs.
How may this translate into clinical impact?  
  • Cath lab activation.  Garvey et al demonstrated that among 14 cath centers, 72% of cancellations were due to ECG reinterpretations.
    • Prehospital setting: As noted in the EMS 12-lead Blog, prehospital ECGs and providers can directly activate the cath lab.  Thus, the use of the modified Sgarbossa criteria and knowledge that a new LBBB alone does not necessarily qualify a patient for cath lab activation. 
    • ED: Improve the ways in which one can read an MI on a LBBB on an ECG (modified Sgarbossa with ST/S ratio)
  • Potentially spare patient unnecessary emergent revascularization. 
  • Ease communication with consultants.  Many cardiologists (such as the one in the above case) have stopped taking patients to PCI based solely on a new LBBB.  
  • So, it's not really about the LBBB, rather the diffusion of knowledge.  Training courses such as ACLS are updated every five years. Thus, if a provider takes a course towards the end of that five years, it may be a few years before they provider is updated.  It often takes even longer to unlearn practices, especially in non-teaching centers. Sites such as TheSGEM and specifically target knowledge translation that may allow for more broad information sharing/collaboration and, perhaps, ultimately improved patient care.
Limitations - There's a fine balance in being an early adopter, a cautious practitioner, a diplomat, a pot stirrer, and a skilled test taker.  Preparing for shifts in thought/practice, "dogmalysis" (word credit to Dr. Cliff Reid) through digestible bits of FOAM, may at least induce greater discussion and consideration in order to achieve this balance.


  1. Looking back at our cases at EMS 12-Lead, it seems we've been pushing for using Sgarbossa and not using "new LBBB" since 2008!

    It is very interesting to see the time lag as standards get updated and guidelines get republished. Thankfully, my local area stays fairly current and is open to pushing ahead of the guidelines.

    (As an aside, I was spoiled during paramedic school as I had access to sites like EMS 12-Lead and Dr. Smith's ECG Blog. Med students and residents alike are lucky to have resources like yours to keep them up to date and ahead of the guidelines.)

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