I received an email today from a reader who ripped me a new one. Here’s the email with my replies interspersed.
To Whom This May Concern,
I stumbled upon this site while looking for additional information on poor r-wave progression. I happened to notice that in the wide-complex tachycardia section, there were some errors I would like to address.
So far so good! I generally appreciate it when someone points out my errors.
First and foremost, no one should treat unstable VT and unstable SVT the same, neither chemically, nor electrically. Unstable VT where losing a pulse is imminent, should be defibrillated where unstable SVT should always be synchronized cardioverted.
The 2005 AHA ECC guidelines classify tachycardias as either stable or unstable. Unstable tachycardias get cardioverted. It doesn’t matter if it’s a narrow complex tachycardia or a wide complex tachycardia. The caveat of course is that you should take steps to make sure it isn’t a compensatory tachycardia and attempt to identify reversible causes prior to cardioversion.
To my knowledge, there is nothing in the literature to substantiate unsynchronized cardioversion (defibrillation) for unstable regular wide complex tachycardias with a pulse.
In fact, having discussed this with various electrophysiologists, there’s no clinical reason why you shouldn’t synchronize the shock for a patient who is pulseless. Why not deliver the current at the optimal moment in the cardiac cycle? ICDs do it all the time, and they don’t check a pulse first.
I’ve researched this question extensively, and I’m left with the conclusion that VT without a pulse was thrown into the VF algorithm for simplicity, and because VT occasionally presents as ventricular flutter, during which time the computer may have difficulty differentiating between R-waves and T-waves. To prevent any delay (or mistakes by inexperienced rescuers) the pulseless VT algorithm calls for defibrillation.
If you have a better explanation, my ears are wide open.
Second, though amiodarone is a useful drug, many EMS departments do not wish to carry it because of its side effect profile, its questionable usefulness in upper chamber dysrhythmias, and its long half-life.
Sounds reasonable to me.
The literature supports lidocaine as being as effective as amiodarone for VT. Lidocaine is not as effective as calcium channel blockers in treating wide complex supraventricular irregular tachycardias however.
But is it dangerous? Is it contraindicated? Obviously not, or L-A-P-B (lidocaine, adenosine, procainamide, bretylium) would never have been the ACLS algorithm for wide complex tachycardias of unknown or uncertain origin.
Third, it is academically dishonest and even perhaps illegal to directly quote from an article without a proper citation.
Is there a particular quote you’re referring to?
It is equally dishonest and professionally unethical to make criticisms of published materials using nothing more than mere opinion.
That’s just crazy talk!
Medical professionals criticize published material all the time, whether it be on blogs, editorials, letters to the editor, podcasts, webcasts, or online discussion forums and listservs.
The entire concept of publishing a paper is to put it out there for your peers to criticize. It’s one of the hallmarks of science.
Furthermore, I found your opinions unfounded, misguided, inaccurate, unkind, irresponsible, and lacking an academic foundation.
It would be extremely helpful to me to know what opinions of mine you found to be so irresponsible.
I advise you to use caution, sound judgement, graciousness, sound ethics and humility when publicly critiquing published materials.
Is this some kind of threat? If you’re going to question my ethics, I think I’m entitled to some examples.
It is a shame, but I cannot in good conscious take the contents of this website seriously. It contains more personal opinion than established fact.
For example?
Furthermore, it appears that the author of the wide complex tachycardia section, who has a noticeably high opinion of himself, is more interested in attempting to sell people on his questionable knowledge than promote truths about electrocardiography.
By all means, enlighten me!
He publicly scathes an author of a wide-complex tachycardia article, but bases it on his own personal opinion, not academically sound research or practice.
Finally, a semi-specific criticism!
I assume you’re referring to my comments at the bottom of Differential diagnosis of wide complex tachycardias – Part I.
I will quote the relevant comments here:
[snip]
I recently discovered this article from the March 2006 issue of Emergency Medical Services. In it, the author states:
With the introduction of new pharmacological interventions that target specific areas of the cardiac conduction system, it has become increasingly important for EMS providers to make an accurate interpretation of an ECG. Though most paramedics have no difficulty distinguishing VT from narrow complex supraventricular tachycardia (SVT), some might fall victim to the “wide + fast = VT” trap when looking at SVT with aberrant conduction. Although VT and SVT with aberrant conduction look similar, they vary greatly in terms of origin, pathophysiology and treatment. Mislabeling dysrhythmias can have severe consequences. Improper identification of VT could place a patient in grave danger by delaying indicated pharmacological and electrical interventions.
Listen carefully.
“Wide and fast = VT” is not a trap! It’s a rule of thumb that exists to protect you and your patient!
The author continues:
A common aphorism among advanced practitioners is, “When in doubt whether a WCT is VT or SVT, treat patients as if they are experiencing VTs.” This stems from a statistic showing that approximately 80% of all WCTs are VT. Though this aphorism is generally a good rule of thumb, it is also important to acknowledge that one in five WCTs is not VT and therefore requires different treatment regimens. One must possess the proper diagnostic tools and knowledge to decide whether a WCT is VT or SVT with aberrant conduction. EMS providers should be able to differentiate VT and SVT with aberrant conduction with confidence and a high degree of certainty.
They do not require different treatment regimens!
Unstable SVT is treated the same as unstable VT! Anyone disagree?
It’s debatable whether or not a stable wide complex tachycardia should be treated in the field at all, but if you do reach for an antiarrhythmic, it better be one that works for SVT and VT (i.e., amiodarone or procainamide).
If you give a calcium channel blocker to a wide complex tachycardia without knowing with 100% certainty that it’s SVT with BBB (or aberrancy) you are a fool.
The article also contains outright errors. Here’s one of the most disturbing.
SVTs with aberrancy will produce either a right or left axis deviation. If the aberrancy is conducted in a RBBB pattern, right axis deviation will be present. If the aberrancy is conducted in a LBBB pattern, left axis deviation will be present. In almost all VT, the axis will be in the extreme right quadrant.
This is nonsense!
In the first place, RBBB and LBBB aberrancy can both show a normal axis. RBBB aberrancy in particular can show a normal axis, right axis deviation, or left axis deviation (bifascicular patterns).
Most cases of VT present with an other-than-extreme axis.
See what I mean about a little bit of knowledge being dangerous?
[snip]
So what it boils down to is I said, “This is nonsense!” and “See what I mean about a little bit of knowledge being dangerous?”
If you’re attacking me on style points, then point taken. I can be a bit brash sometimes. However, I stand by the principle behind my words. Using QRS morphology to differentiate between VT and SVT with aberrancy is a dangerous, error-prone skill.
Use it at your own peril.
Though I do not know the person’s background, it forces one to wonder whether this blogger is educated beyond what his own intelligence permits.
You are entitled to your opinion.
This has the potential to be a good website, but lacks credibility. I will avoid this site and advise others to do so until it can be based on a solid foundation of knowledge. Personal opinion does not cut it.
Thank you,
Matthew Paulus, BME, EMT-P, MS-S NP-S/Cardiopulmonary CNS-S
It’s a big Internet, Mr. Paulus. There are plenty of URLs to choose from. I’m sorry the Prehospital 12-lead ECG blog was not more to your satisfaction.
Have a wonderful day!
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