Sometimes recognizing sinus tachycardia can give us fits.

What? Sinus tachycardia? One of the most basic rhythms?

The discussion that follows will highlight some of the difficulties sinus tach can present at high rates. The pitfalls of using the generalized term "SVT" will also be discussed. This discussion is not meant to imply that this issue is easy to navigate. It can get very difficult, and very dicey. The consequences of misinterpreting the rhythm and missing sinus tach can have very deleterious effects for our patients.

We are all good at recognizing sinus tachycardia at rates between 100-150, but when rates exceed 150 it seems to become problematic.

Is it difficult to recognize this?

No.

How about this one?

More difficult.

When sinus tachycardia occurs at high rates, our ability to correctly differentiate it from other types of SVT apparently decreases. P waves start to blend into the T waves. Instead of talking about discreet stand alone P waves, we talk about "notches" and "bumps". It is all too easy to look at a rate >150 and simply call it "SVT".

We know what sinus tach is: a sinus rhythm at rates faster than 100 (in adults), which is a normal physiological response to compensate for the increased needs of the body. I won’t spend time listing all of the possible causes, ranging from running around the block to septic shock.

AVNRT, a type of SVT that is responsive to Adenosine, is a re-entrant tachycardia that relies on a circuit through the AV node to sustain it. Block down the AV node, and the dysrhythmia terminates. Quite a bit different from sinus tach. Different mechanisms, different treatments.

Several case studies involving the above strips and ones like it have appeared on our FB page, and the FB pages of other EMS educational sites. What we have seen is that an alarming number of folks incorrectly identify sinus tachycardia as one of the other SVTs and want to treat with Adenosine or cardioversion.

Consider this rhythm strip that appeared on our page and another educational paramedic page:

The patient was a sick adult male, hypotensive. P waves are subtle, but they are there. Due to the rate, however,  a majority of providers (hundreds!) identified this as "SVT" and wanted to immediately cardiovert. 

Here is the followup ECG taken a couple of hours later. The patient was severely dehydrated and had received a few liters of fluid:

Now that the rate has slowed, sinus tach is clearly visible.

While we are discussing this, we should be clear about our terminology. Sinus tach is one of the Supraventricular Tachycardias. "SVT" is an umbrella term that represents a group of tachydysrythmias that originate above the ventricles. They will generally be narrow tachycardias, unless aberrant conduction is present. Some of the other types of SVT are AVNRT, AVRT, A-Flutter, A-Fib, junctional tachycardias and atrial tachycardia. Not only is sinus tach one of the SVTs, it is by far the most common SVT!

One of the issues that’s come to light is the fact that “SVT” is seemingly often taught as a “dysrhythmia” itself rather than what it really is: a group of dysrhythmias. I really don’t like the term “SVT” because it implies a diagnosis, when in fact it should motivate a provider to form a list of differentials and consider the H’s and T’s.

"Could this be sinus tach? A-Flutter? AVNRT?"

Treating "SVT" as a stand alone dysrhythmia leads folks to believe there is one “treatment” for SVT, when in fact the treatment is determined by which type of SVT the patient has.

What are we even taught about SVT?

Generally speaking these days, when students are taught SVT they are taught that a narrow tachycardia faster than 150 or 160 is "SVT". Simple as that.

How do we differentiate sinus tach from SVT?

That’s easy: rate!

If the rate is over 150 (some use 160), then it is “SVT and not sinus tach” and should be given adenosine or cardioversion! Quickly!

If you were taught that, raise your hand. Wow… that’s a lot of hands!

While we are on the subject, where did the rate limit of 150 or 160 come from?

I have NO IDEA. There does not seem to be any research I can find that even suggests that these numbers can be used to differentiate ST from other SVTs.

In fact, I could not find any research that demonstrates that absolute rate plays any part in differentiating ST from other SVTs.

All I could find is references to the guideline used to determine the theoretical maximum sinus tachycardia in healthy people: “220 – age”.

This “formula” is a guideline at best. It intends to illustrate that very young people can have ST at very high rates, and that as we age, it should be more difficult to achieve higher rates of sinus tach.  However, we deal with really sick patients, and theoretical guidelines are not good enough to help us with this issue.

What I know is what you all know. That medics are taught that at rates above 150, you can no longer see P waves, so you have to assume it is “SVT”.

“154= SVT”

“146= ST”

Easy as pie! Whether or not P waves are visible does not seem to factor into the equation.

Perhaps you don’t want to accept that these teachings do not seem to be based on anything concrete, but these are the facts. Sinus tach commonly exceeds rates of 150, and P waves are often discernable. More on this in a bit.

In any event, It is in this region of rates, between 150 and 200, where sinus tach is often mistakenly called “SVT”, and the risk of inappropriate treatment rises. Don’t believe it?

Before you can say “SINUS TACH”, I could show hundreds upon hundreds of comments left by medics stating that a rhythm “could not be sinus tach because the rate is over 150”.  And these comments were made by the medics who are motivated enough to visit educational sites and participate. 

The result of this is that too many medics are not correctly trained to deal with this issue. Sinus tach is unrecognized. The P waves are ignored, and the rhythm is labeled “SVT”, and the patient is in danger of suffering in more than one way:

For staters, they may receive an inappropriate treatment. A sick patient in sinus tach does not need to go through trials of adenosine, or even worse, cardioversion.  In addition to the discomfort, those treatments won’t work. Sinus tach is not a reentrant rhythm that relies on the AV node for its perpetuation, so adenosine or cardioversion won’t resolve the arrhythmia.

One of the most overlooked consequences of mistreating this rhythm is the fact that these patients are not getting the treatment they really need. These patients need lots of fluids. If medics are giving drugs and electricity, they certainly are not administering large boluses of NS.

It is easy to imagine how difficult the choice may seem. The sick patient in sinus tach will look shocky. He may have palpitations or chest pain, and may be altered. In other words, it will be very tempting to attribute the patient presentation to rate problem, even though the rate is compensating for their underlying medical issue.

Without a sound understanding of what sinus tachycardia really is, and what rate ranges are reasonable, it becomes much more difficult to make the right choice.

Probably right about now, some of you will want to blame ACLS for all of this. Consider the 2010 “Adult Tachycardia (with pulse)” algorithm ^[1]:

Box 1 states: “Heart rate typically greater than or equal to 150 if tachyarrhythmia”. 

What does that mean? What it seems to mean to a great many people is that a rate greater than 150 is "SVT".

If the patient appears unstable, we are performing synchronized cardioversion by box 4. There is no mention of sinus tach anywhere on this algorithm.

I’ll admit, I think that algorithm could be better. I think there should be a box that gets you out of that algorithm if sinus tach is recognized, similar to what appears on the ACLS Pediatric Tachycardia algorithm ^[2]:

Here, if the tachycardia is narrow, you are directed to one of two boxes which require you to assess for the presence of sinus tachycardia. I believe that a box like this in the adult algorithm would help clear up a lot of confusion.

In defense of the AHA, however, the simplified algorithm is based on the assumption that students have read the ACLS Provider Manual, on which the algorithm is based.

The following appears in the “Foundational Facts: Understanding Sinus Tachycardia” box on page 125:

           “Sinus tachycardia is caused by external influences on the heart, such as fever, anemia, hypotension, blood loss, or exercise. These are systemic conditions, not cardiac conditions. Sinus tachycardia is a regular rhythm, although the rate may be slowed by vagal maneuvers. Cardioversion is contraindicated.” ^[3]

Clearly, on page 125 of the ACLS Provider Manual, sinus tachycardia has been excluded from the adult tachycardia algorithm. It is a shame that fact is not reflected on the algorithm itself, because evidently a very large number of ACLS students do not read the manual and may incorrectly assume that rate is the determining factor.

I know some of you are thinking, “is this much to do about nothing? Is sinus tachycardia at rates above 150 as rare as an isolated posterior STEMI?"

We put this issue to the test. We brought in two well known electrophysiologists, Dr.’s John Mandrola and Mark Perrin, to shed light on this issue and share their perspectives with us. Readers of our blog will recognize them as past contributors and experts in their field.

I asked Dr. Mandrola about the utility of the “220-age” formula, and here is what he had to say:

           “The old formula 220- age equals the max heart rate represents only an estimate. It can vary by up to 10-15%. That's a lot. Normally a 30 year-old would have a max of 190. But with the variation, ST could be as high as 200. I see tons of patients for 'tachycardia', that's supposedly abnormal. Often its just ST. The short answer is that human heart rates vary quite a bit–at the high and low end.”

I then asked him what we really want to know: how common is ST at rates above 150:

          “The sinus node is highly innervated with both sympathetic and para-sympathetic neurons. Adrenaline can easily push the sinus rate above 150. Stress, anxiety, fever, dehydration, drugs, heat, and many other things can do this.  

            If a patient has upright p-waves and the diagnosis is ST and is unstable, it's not because of a primary electrical disturbance. ST is a sign not a primary arrhythmia. Patients with ST should be resuscitated, but not with shocks, with fluids, oxygen and rest perhaps and comfort perhaps.”

I asked Dr. Perrin for his thoughts about using a rate of 150 as a cut-off between sinus tach and other types of SVT and he had this to say:

            “Thinking that ST has an upper limit of 150-160 is kind of crazy. The septic, those in congestive cardiac failure, people with pulmonary emboli, hemorrhaging patients, etc, etc… all of these could hit heart rates of 190-200 or higher.

                 It is an easy diagnosis to make as well – because the P will always be present. Perhaps if the rate is > 200 it may disappear into the T wave a little. The only real differential is atrial tachycardia/flutter, and this is pretty unlikely to destabilize a patient.”

We discussed the issue medics are having in the field with inappropriate treatments of sinus tachycardia. I asked if he had any first hand experiences with it:

           "In fact, I have found, anecdotally, that paramedics are quick to shock patients. I have misgivings about this, especially for narrow-complex rhythms. We live in a city. ERs are close by. Why shock so quickly? There's some data that shocks harm the heart.”

My sincere thanks to Dr.’s Mandrola and Perrin for their contributions. As always, peer sourcing is great way to gain additional insight and expertise.

Hopefully this discussion has been educational for those who thought that 150 was any kind of limit for sinus tachycardia. The fact of the matter is that sinus tach at rates between 150- 200 not only exists, but is not uncommon. We need to be better at assessing for sinus tachycardia, because it is the most common SVT. We need to make sure we are doing right by our patients, giving them what they need and keeping them our of harm's way.

We also need to be better educators and providers.

Some will say, "we are teaching to the Registry", or "we are teaching to ACLS".  

They will say, "in the real world, they will know what to do".

From what I have seen, it doesn't work like that. Providers fall back on what they were taught, which often happens to be incorrect.

It begs the question, why are we teaching something we know is not correct? That can't be good for anyone.

For those who didn't know this information before, you know it now. Let's see if we can change the way we educate and provide care in this area.

It seems to be a deeply rooted problem, ingrained in decades of education. Time for a change. I don’t know if the issue has been raised before, but we are raising it now. 

As always, I look forward to your comments!

_

Footnotes:

^[1],[3]-  Advanced Cardiovascular Life Support Provider Manual

                  2011, American Heart Association

^{[2]             Pediatric Advanced Life Support Provider Manual}

                  ^{2011, American Heart Association}

EMS 12-Lead podcast – Episode #11 – Are we harming patients with oxygen?

In this episode of the EMS 12-Lead podcast we're joined by Kelly Arashin, ACNP, CCNS and Mike McEvoy, PhD, RN, CCRN, REMT-P at EMS Today 2013 in Washington D.C. We discuss the benefits and dangers of oxygen administration. 

Kelly is a dual boarded advanced practice nurse and Chair of the Hypothermia Steering Committee at Hilton Head Hospital in Hilton Head Island, SC.

Mike describes himself as a nurse, paramedic, firefighter, and medical college professor. He is also Chair of the Resuscitation Committee for University Teaching Hospital in Albany, NY.

Mike is the author of the article Can Oxygen Hurt? and taught an educational session at Physio-Control University entitled To Give Oxygen or Not: That is the Question. 

*** Update ***

Thanks to Brooks Walsh, M.D. for bringing this article to our attention:

Association between arterial hyperoxia following resuscitation from cardiac arrest and in-hospital mortality

Tom Bouthillet, Kelly Arashin, Mike McEvoy at EMS Today 2013

Special thanks to Physio-Control, JEMS, PennWell, and the ProMed Network

You can also watch the video version.

See also:

Follow Kelly Arashin on Twitter at @BarefootNurse24

Visit Kelly's blog

Follow Mike McEvoy on Twitter at @McEvoyMike

Visit Mike's website

Subscribe to the EMS 12-Lead podcast on iTunes

Ivan Rokos, M.D. has referred to primary PCI for acute STEMI as “the most complex, multi-disciplinary, and time-sensitive therapeutic intervention in the world of medicine.”

The emphasis on door-to-balloon times, and more recently, first medical contact or EMS-to-balloon times has transformed how acutely ill patients suffering heart attacks receive timely reperfusion in many communities, because as we’re so often told, “time is muscle.”

While some believe that the emphasis on door-to-balloon times has unintended consequences, in our opinion the real-life stories of the men and women who build these systems of care illustrate the very best of what modern medicine has to offer.

A single 9-1-1 call (9-9-9 in the UK) triggers an awe-inspiring series of highly coordinated events that clearly demonstrate that despite all of our arguments about health care and how it should be paid for, when a fellow human being is in danger, we will work together to save that person’s life.

We will exercise exceptional caring and competence, and then return that patient to their family. We give them another chance.

That’s powerful.

Many of us in EMS (and other areas of medicine) love survivor stories because it makes us feel good to know we’ve helped another human being. That’s why we got into medicine in the first place. But then something happened. We became jaded. We became cynical. We saw the worst in people.

The Code STEMI Web Series is a salute to the individual EMTs, paramedics, nurses, and physicians who had the courage and the insight to change the status quo and build something very meaningful that directly influences whether our friends, neighbors, or even our family members live or die.

Change can be difficult. It can be painful. It takes us out of our comfort zone and sometimes it rearranges the pecking order. Yet, we must change, whether it’s allowing EMTs to acquire and transmit a 12-lead ECG, activating the cardiac cath lab at 3:00 a.m. Sunday morning, or learning how to reduce “door-in to door-out” (DIDO) times at Critical Access Hospitals so that heart attack patients have the best possible chance of survival.

As Michael Hibbard, M.D. reminds us, it’s not the strong who survive. It’s those who are most able to adapt to change.

Our most recent episode of the Code STEMI web series looks at the London Ambulance Service. It is the busiest, and arguably one of the best EMS systems in the world. We interview front line EMTs, paramedics, nurses, and physicians as well as survivors. We hope you enjoy watching it as much as we enjoyed filming it so you can share our enthusiasm for witnessing a job well done.

Follow the #CodeSTEMI hashtag on Twitter!

Seaon 2 of the Code STEMI Web Series is set to launch on March 7, 2013 at EMS Today in Washington, D.C.! This season starts out with our most exciting location ever — London, England as we feature the London Ambulance Service (LAS).

You can follow the series at First Responders Network or at CodeSTEMI.tv.

Special thanks to Physio-Control for sponsoring this web series!

Speaking of which, you can download the schedule for Physio-Control University at EMS Today by clicking here (PDF).

I'll be teaching an educational session called Hilton Head Island – Strengthening a Community's Chain-of-Survival. I'll explain how we achieved on of the highest cardiac arrest save rates in the nation (Utstein survival of 66% for 2012).

Hope to see you there! 

When we left off, our patient was in the back of the truck with a burning sensation radiating to his back. We had run a 12-Lead ECG and our partner was wondering which facility you wanted him to drive to.

To answer that question, we should look at the 12-lead!

This 12-Lead shows a normal sinus rhythm at 70 bpm without ectopy or bundle branch block. A case could be made for incomplete right bundle branch block given a QRSd of ~110ms. Strikingly we have ST-depression in I, aVL, and V1-V5 with ST-elevation in lead III. Anytime you see flat or downsloping ST-depression in aVL you should look for elevation in the inferior leads (typically III). When present, it is almost certainly an inferior wall MI.

Many readers commented that the ST-depression in V1-V5 could be either a sign of a posterior wall MI or a "anterior ischemia". It is important to remember that ST-depression from ischemia does not localize! This concept is so important, I'm going to list it again:

ST-depression from ischemia does not localize.

Traditional evaluation of ST-depression has taught that focal ischemia may cause localized ST-depression, however, this is not the case. Subendocardial ischemia causes diffuse ST-depression and will not be found in a localized pattern. Any time you have localized ST-depression you must consider it to be a reciprocal change first!

In our case, we have ST-elevation in lead III which clinches the diagnosis of an inferior wall myocardial infarction with possible posterior extension. A subsequent ECG revealed evolving ST-elevation in the inferior leads:

Remember, all patients who receive one 12-Lead should at least receive a second 12-Lead! If you were not comfortable activating a STEMI from the first clean tracing, serial 12-Leads provide improved diagnostic sensitivity. A single 12-Lead may only identify ~80% of STEMI patients.

The paramedics in this case recognized this fact, activated a STEMI alert, and transported the patient to their nearest PCI center. The in-hospital ECG showed continued evolution of the IWMI with the most impressive elevation and depression of the patient's clinical course:

They achieved an impressive 83 minute first medical contact to balloon time with one stent placed in the RCA.

We hope you've enjoyed this case as much as we did, but more importantly this case presents some great teaching points:

• Sometimes STEMI patients will have atypical symptoms.
• A single ECG is not enough to detect all STEMI patients, serial 12-Lead ECG's should be acquired on all patients who receive one.
• ST-depression from ischemia does not localize, localized ST-depression should be considered a reciprocal change until proven otherwise.

It is a blustery Christmas morning when you and your partner are dispatched for a 47 year old male with chest pain. Firefighters are already on scene obtaining a history and vitals when you arrive.

You check in with the officer in charge, a paramedic, and he reports that the patient has been having a "burning sensation" in the middle of his chest, going to his back. As it is Christmas morning and the patient's family is opening presents, the officer also relays the patient, "is likely going to refuse." He also relays that they witheld ASA due to the patient's "indigestion."

One of the firefighters gives your partner the patient's vitals:

• HR: 70 bpm, regular at the radials
• BP: 144/96
• RR: 18, unlabored, in no apparent distress
• SpO2: 95%
• ECG: "normal sinus, nothing out of the ordinary" (no 12-Lead was captured)

You perform a quick patient assessment prior to making any decisions:

• Onset: 21:00 the prior evening
• Provocation/Palliation: pain went away over night with sleep, came back after breakfast; nothing makes it better now
• Quality: "burning"
• Radiation: "straight thru to my back"
• Severity: 7 of 10
• Timing: constant burning

A focused history reveals no prior cardiac problems and that the patient takes no medications and has no allergies.

Given the patient's symptoms and possibility of a true cardiac problem you advise the patient that a trip to the hospital is worth it just to make sure he's not experiencing something serious.

After he sits down on your stretcher your partner begins placing electrodes for a 12-Lead as you gather four baby aspirin for the patient to chew.

You notice the artifact and hit print again, however, you decide you can run another one in the truck. After loading the patient your partner hands you the second 12-Lead, which is a bit cleaner than the first.

Not completely satisfied, you run a 3rd 12-Lead in the back of the truck.

Your partner asks which facility you'd like to go to.

• What do these 12-Lead's show?
• What are your next steps?
• Is indigestion a contraindication to aspirin administration?
• Are you glad this case does not involve a narrow complex tachycardia?

I'm starting with left anterior fascicular block… well, just because!

I hope you find these to be useful!

See also: Left anterior fascicular block

It is a sunny January afternoon at the ER when you are called to see a 57 year old male complaining of feeling "really sick".

You find your patient lying in the bed in room 3. He looks pale and short of breath. You introduce yourself and ask him why he has come in today.

He says:

"About two weeks ago, I started feeling short of breath, with a cough. I got much more tired than usual. I went to see my doctor, who said I had an upper respiratory infection and prescribed me some antibiotics. I rested at home for a few days, and started to feel a little better. Then, I began to go downhill again. Felt so awful today, barely have enough energy to walk, so I had my wife drive me to the ER."

He tells you that he has a history of hypertension and is a pack a day smoker, although he is trying to quit., Prior to getting sick, he has felt pretty well. In fact, he tells you that he started a work out regiment to lose some of the excess weight he is carrying.

Your patient tells you he hasn't been eating or drinking well lately, and he is hypotensive at 86/58.

As you are running through your list of differentials, the tech hands you this 12 lead ECG:

You take a look at the ECG, and a couple of thoughts come to mind. You have an idea of what might have happened.

You tell Mr. Wilson that you want to run a few tests…

So, what do you think is wrong with Mr. Wilson?

If you would like to refresh your memory on Part I visit here.                                         

Dr. Walsh and I spoke about why he thought hyperkalemia presented such a challenge for EMS providers:

"The recognition and treatment of hyperkalemia is one of those areas in medicine where, despite strong and clinically relevant results in the literature, the "usual practice" keeps kicking along. This is like a lot of areas in medicine, true."

With that said, let us continue with Myths and Facts about Hyperkalemia Part II:

Myth: The ECG shows a predictable sequence of changes as the potassium level increases

Experiments done on (presumably) healthy animals demonstrated a progression in ECG derangements as potassium levels were experimentally raised. A number of textbooks and review articles repeat this result, even though numerous human clinical studies have failed to replicate a linear relationship between the potassium level and specific ECG findings.

We start 2013 with a continuation of our discussion about the field treatment of hyperkalemia. 

It might be helpful to review the first part of the discussion," HyperK and Shades of Grey" here. 

We are fortunate to have as a guest contributor Dr. Brooks Walsh of the Mill Hill Ave Command blog. An advocate of prehospital medicine, Dr. Walsh offers shares "Myths and Facts" of hyperkalemia with us. My sincerest thanks him for his valued contributions! 

I asked Dr. Walsh why he thought hyperkalemia presented such a challenge for EMS providers. Here is what he had to say:

"The recognition and treatment of hyperkalemia is one of those areas in medicine where, despite strong & clinically relevant results in the literature, the "usual practice" keeps kicking along. This is like a lot of areas in medicine, true.

But rather than curse the darkness, I wanted to go over some newer perspectives on hyperkalemia. Now, I don't want to simply reiterate all the great material that Dr. Weingart talked about on EMCRIT, so you really ought to download his great podcasts on the treatment of hyperkalemia and on why Kayexalate is likely ineffective, if not outright dangerous. The podcasts are real short, so just play them right now.

With that said, I'd like to review a few topics in hyperkalemia that deserve more attention:

Myth: Dialysis patients tolerate hyperkalemia better than other people.

Medicine is funny. I mean, there are "facts" that "everyone knows," but that are surprisingly hard to prove in studies. This is sort of one of those kind of facts, with very little evidence, and plenty of "real world" experience. Should we continue to believe it?

Maybe. It kind of depends on what we mean by "tolerate." If we mean "don't show ECG signs of hyperkalemia," then maybe dialysis patients do "tolerate" hyperkalemia better than other people. 

It's kind of hard to answer this definitively, though, since ECG signs of hyperkalemia, especially in the moderate range (e.g. < 6.5), are often absent on the ECG on all patients. We just don't see that many patients, dialysis or no, with severe hyperkalemia. Even in a study that looked only at dialysis patients, the vast majority had a K < 5.2, and ECG changes were accordingly infrequent.

But it may also be that dialysis patients, in fact, do show fewer signs of hyperkalemia on the ECG than do other people. A study done back in 1967 looked at dogs that received IV potassium slowly or quickly (but ending up at the same blood level). The faster infusions caused more ECG and hemodynamic effects. It is possible that ESRD patients, with a presumably slow increase in potassium levels, show fewer ECG changes than, say, a patient with acute rhabdomyolysis.

But the ability to avoid ECG changes isn't the "tolerance" we care about in hyperkalemia - we really care about the potential for patients to go into cardiac arrest. Hyperkalemia, regardless of ECG signs, puts the patient at risk for fatal arrhythmias. If you have either lab results or ECG evidence of hyperkalemia, that patient needs to be treated immediately – on that, most experts agree. I couldn't find any mention in the literature that suggests otherwise. For example:

                   "We emphasize that despite the absence of ECG changes of hyperkalaemia in ESRD, hyperkalaemia is still a     potentially life-threatening condition." –Aslam 2002

Or

"Some experts advocate calcium administration in patients whose serum potassium is >6.0–6.5 mm, even in the absence of EKG changes." –Putcha 2007 

 

Myth: If the ECG doesn't show QRS widening, then the patient is at low risk.

Some clinicians are under the impression that you can wait to treat the hyperkalemia until the QRS is "incredibly widened," showing huge sine-waves.  An ECG that shows "just T-waves" is presumably at lower risk, in this view.

Except that's not how it works, according to the experts. As these nephrologists explain:

                 "Five medical textbooks (two nephrology, two internal medicine, and one emergency medicine) advocate calcium gluconate in all hyperkalemic patients with EKG changes. "

Or this critical-care nephrologist:

                "It is apparent that neither the EKG nor the [potassium level] alone is an adequate index of the urgency of hyperkalemia,… hyperkalemia should be treated emergently for 1) K > 6.5 mmol/L or 2) EKG manifestations of hyperkalemia regardless of the [level]." –Weisberg 2008 "Management of severe hyperkalemia"

We asked Dr. Smith about his experiences with this topic, whether he has seen patients arrest without going through the ECG transition to widened, sine wave ECGs. His response as well was that "I have seen v-fib with peaked T waves only" on the ECG.

Stay tuned for "Myths and Facts Part II"!