Another ‘Routine’ ECG

You’ve just started your shift in your regional ED when one of the staff members asks you to review a routine ECG of a 19yo female with cellulitis of the right leg.

What do you think of this ECG?

You kindly ask the staff member to perform another, with the amplitude doubled…

Cardiac pre-excitation

“Bulldust!” I hear you say; “There’s no delta wave!”

Well, not all that is pre-excitation is Wolff-Parkinson-White (WPW). WPW is the classic example of pre-excitation that is taught in medical school, pops up from time to time in practice and frequently trotted out (zebra trotting of course) as a random answer to a straightforward question during rounds.

Cardiac pre excitation describes the premature activation of the ventricles; the classic form being WPW, characterised by a short PR interval and a slurring of the QRS (the delta wave). This premature activation in WPW is caused by a band of myocytes bridging the atrioventricular junction (the bundle of Kent). This band inserts into the ventricular myocardium which conducts slower than the bundle of His and Purkinje fibres, hence the characteristic delta wave.

Looking at this ECG, you can see that there is a short PR interval (<0.12s) but no delta wave.

There are other pre-excitation syndromes that have been described, including the Lown-Ganong-Levine (LGL) syndrome, Enhanced Atroventricular Nodal Conduction (EAVNC) and Mahaim Fibre Tachycardia. Unlike WPW, the postulated pathways for these pre-excitation syndromes terminate into or near the conducting system, hence no delta waves. To make things even more complicated, pre-excitation syndromes can have a completely normal looking ECG too..

“Chris, I’m silently aspirating with boredom here, just tell me, what does this mean for the patient?”

Well, like WPW, these patients can suffer from a number of supraventricular tachycardias, such as atrioventricular nodal reentry (AVNRT) and orthodromic atrioventricular rentry (AVRT). They can also experience a rapid ventricular response from AF or atrial flutter.

Bottom Line

Remember that not all pre-excitation is WPW, don’t just look for the delta wave, remember the PR interval – in the first timer SVT you might see something that will prompt an early referral to a cardiac electrophysiologist.

P.S. I don’t know yet which pre-excitation syndrome this is, when I hear back from the electrophysiologist I will update the post.

P.P.S. I will get some better images of the ECGs soon! I seem to have issues with the degradation of image quality from my camera to my mac.

References

  • Podrid, PJ. Lown-Ganong-Levine syndrome and enhanced atrioventricular nodal conduction. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2013.
  • Podrid, PJ. Mahaim fiber tachycardias. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2013.

#CLaPSem01

CLaPS (Crowd Learning and Problem Solving) is an idea I had on the flight back from SMACC 2013. The idea is to use the power of Twitter and Storify via pre-determined hashtags to capture and publish discussion around a particular clinical problem.

The clinical cases will have multiple issues and will often have more than one approach (as is often the case in medicine). Those contributing to the discussion are encouraged to provide links to evidence as needed. The discussion will be captured on storify after 1 week and published on the website.

If anyone has any suggestions for a CLaPS case feel free to contact me.

 

Now onto the first CLaPS problem – #CLaPSem01 (emergency medicine case 01)

 

Don’t Tell Me What To Do!

It’s another busy day in your metropolitan emergency department and you are a registrar (US = resident) seeing Kim, 16 year old female, weighing 65kg (140 lbs) with a paracetamol overdose.

Kim tells you she was feeling down as her friends had gone to a party without her. She had swallowed approximately 17grams of paracetamol (acetaminophen) 7 hours ago. Her mother had come home to find the empty packets strewn around the house and despite Kim’s protests, was brought to ED.

Her past history includes asthma, for which she has had 5 previous ICU admissions with intubation, the last one being 4 months ago with a ventilator wean period of 3  weeks. She is compliant with her use of preventers and relievers.

You quickly place an IV and start a NAC infusion. Shortly after it begins she becomes acutely short of breath and becomes quite anxious. You stop the infusion and give her salbutamol and her symptoms slowly resolve.

When you go to restart the infusion, she refuses. You explain the kind of reaction NAC can cause and that it is not a true allergy and offer to start therapy to help prevent it happening again but she continues to refuse. You explain the reasons for the NAC infusion and the consequences of untreated liver disease and she refuses.

Her mother talks with Kim and asks you to start the NAC infusion despite Kim’s protests.

 

A number of issues in this case, please contribute to the discussion by posting your comments on twitter under the hashtag #CLaPSem01 If you don’t include the hashtag, your comments won’t be captured. If you need more than 140 characters (and you might do for this one!) feel free to comment below!

Don’t know how to use twitter? Try Dr. Tessa Davis’ excellent tutorials at http://lifeinthefastlane.com/reviews/techtuts/

Thank you for supporting this new concept

Teacher, leave the kids alone!

Today the inestimable Chris Nickson (@precordialthump) posted an article on LITFL on the concept of a curriculum for #FOAMed. This generated some interesting introspection on my part and a fascinating discussion on twitter. It’s prompted me to publish my own views on the concept of #FOAMed and how it can relate to one’s own learning needs, from a training perspective.

Firstly, a bit of educational theory (just a little, I promise no Miller’s Pyramids!).

David Kaufman wrote an excellent article in the BMJ in 2003 called Applying Educational Theory in Practice . In it he outlined 5 assumptions about adult learning (aka Andragogy).

 

  • Adults are independent and self directing
  • They have accumulated a great deal of experience, which is a rich resource for learning
  • They value learning that integrates with the demands of their everyday life
  • They are more interested in immediate, problem centred approaches than in subject centred ones
  • They are more motivated to learn by internal drives than by external ones

 

Looking at these principles, it’s easy to see why #FOAMed has become so popular in such a short amount of time. There are no demands on you from #FOAMed to learn particular things, instead you choose what to study based on your own needs. You can choose when to study it, based on your own time demands and you can choose how to study it, through the use of different media (podcasts, blogcasts, videos, pictures, case discussions).

I don’t believe #FOAMed needs to implement standards/rules/QA as a requirement for publishing under the #FOAMed ‘brand’. Instead the #FOAMed community should be allowed to self-police content. The ‘O’ in #FOAMed stands for Open; this means all content published must be open to critical appraisal and discussion in a non-threatening environment. Introduction of rules or QA may actually threaten this concept!

If we want #FOAMed to remain the fantastic andragogic learning tool it is now, we must promote this open environment and we absolutely must encourage all members to critically appraise all content. We must remind users to think about the information we read/listen/watch and ensure it applies appropriately to our own clinical practice/skill level as well as our particular patient population.

 

The Shoulder Whisperer

I’ve tried the Cunningham technique for anterior shoulder relocations several times, without success. Each time I failed I went back to the video and tried to identify where I went wrong.

Recently I was successful and what a feeling! The staff were impressed, the patient was pleasantly shocked and they were discharged from the department within an hour of arrival.

So I thought I’d share with you my tips for successfully performing the Cunningham techique to reduce anterior shoulder dislocations.

  1. Comfort is Key – If they are in a lot of pain, it won’t work as they will continue to tense their muscles. Analgesia and/or light sedation can help
  2. Posture is a Priority – Make sure the patient sits up straight, squaring their shoulders, pushing their chest out, reducing scapula anteversion. You will need to constantly remind them of this
  3. Weird is Wonderful – Tell them at the start, if the shoulder feels ‘weird’ or they feel movement, ignore it, don’t fight it and let it happen
  4. Shun the Shoulder – If you want this to work, they need to trust you and relax, when you touch near the shoulder, you will hurt them and they will tense
  5. Routine is Right – Get a routine, for me, this involves a repeating cycle of posture reminders and idle chit chat – all while steadily massaging the mid bicep. Tell some jokes, talk about sport, whatever you can say to take their mind off their shoulder
  6. Two for Traps – If you have a second helper (I had a very helpful nurse) get them to lightly massage the trapezius at the same time, staying away from the shoulder

I hope that helps. If you have any other tips to share, please feel free to comment below.