How To Interpret Inpatient Cardiac Telemetry

Continuous cardiac telemetry monitoring, or ‘tele’ colloquially, is how we remotely monitor patients’ heart rhythms while in the hospital. When it is used appropriately it is a valuable diagnostic tool that assists in diagnosing and managing specific abnormal heart rhythms. I use it everyday for post-myocardial infarction patients (those who just suffered a heart attack) to monitor for ventricular ectopic beats caused by ischemic myocardium (dead heart tissue). Unfortunately tele review is one of those lessons thrown into the hidden curriculum of medical training where people are often taught it on the fly without much guidance. Electrocardiogram, or ECG, interpretation is outside the scope of this post. Instead I will focus on a few helpful tips to help improve your ability to understand and utilize tele in a more meaningful and intentionally manner for any nurse, physician assistant, nurse practitioner, intern, resident, or incoming cardiology fellow. Lastly, don’t forget to subscribe so you don’t miss future posts!

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1. Not everyone needs tele

Rule number one in medicine is ‘primum non nocere’ or ‘first do no harm’. Exposing patients to unnecessary monitoring can lead to further unnecessary testing and in turn possible harm. Not only is ordering unnecessary tele potentially harmful to patients but it is also costly. The average hospital bed is more expensive if telemetry is added on. It also can harm healthcare professionals through alarm fatigue. Think about how frequently those things beep along with every other alarm in the hospital. Not to mention how annoying actually wearing a tele monitor can be for patients (1). Inappropriate tele use is such a widespread issue in the United States that it is one of the cornerstones of the Choosing Wisely campaign from the Society of Hospital Medicine (2). Tele should be treated like any other imaging study and only be ordered for specific patients when indicated.

2. Evidence behind tele

No large randomized control trials have established standards of care for cardiac telemetry. However as the old adage goes you don’t need an RCT to prove that a parachute is useful when jumping out of an airplane. There are guidelines established by the AHA/ACC but they are just that- guidelines. In the end, you have to use your clinical judgement when ordering or discontinuing tele. Some of the obvious clinical scenarios when telemetry is useful include

Syncope of unexplained origin (meaning if the patient has obvious vasovagal syncope then you don’t need tele!)
Uncontrolled or unstable arrhythmias (AF RVR, VT)
Following a STEMI
ICU monitoring

3. Common reasons for inappropriate tele use

In residency I attempted to combat inappropriate tele use through a quality improvement project. While partially successful I found that there were a few common diagnoses that accounted for a majority of inappropriate tele use. In the New England Journal of Medicine (NEJM) Journal Watch, Dr. Winawer summarized my thoughts quite well in his post detailing top 10 reasons he has anecdotally seen over his career for inappropriate tele monitoring (5). Remember that these are anecdotes for tele use on the general medicine wards and exclude critical care units. Here are 5 of the most common reasons I see patients inappropriately placed on tele.

1. Abnormal electrolyte derangements. You should not be using tele as a surrogate marker for electrolyte abnormalities. You should be managing the patient with frequent BMP’s. If they have ECG manifestations then they should not be on the general medicine floor and should be in a higher level of care. This include patients with End-Stage Renal Disease (ESRD) with chronically abnormal potassium levels without ECG changes.
2. Low-risk chest pain. If you rule out ACS with negative serial troponin you can DC tele.
3. Non-cardiac syncope. If a patient has a syncopal episode due to hypoglycemia or a seizure then tele has zero utility.
4. Sinus tachycardia. Sometimes patients are admitted for non-cardiac issues and are found to have appropriate sinus tachycardia. This could be due to a fever, pain, anemia, or dehydration. Tele is sometimes used as a surrogate for ‘closer patient monitoring’. If a patient needs to be monitored more closely then they should be upgraded to a higher level of care. Tele is not an adequate replacement.
5. History of atrial fibrillation. If a patient has a history of AF but is rate controlled they do not require tele monitoring. This often happens with patients admitted for something non-cardiac like cellulitis and placed on tele despite being hemodynamically stable.

4. Evaluate the need for tele daily

It is far harder to stop a medication than it is to start one. Same thing is true for tele. So each day that you check your patient’s tele remember to ask yourself if it is even necessary in the first place. This is a responsibility of everyone who interacts with the patient from bedside nurses to the advanced practitioner PA or NP, to both the primary physician and consulting physicians. Everyone has the ability to contribute to more meaningful tele use in the hospital- even our patients!

5. How to look at tele systematically

Okay, okay, okay. I get it. Only order tele when it’s indicated and discontinue it when appropriate to do so. So let’s say we have a patient on tele. Where do we start?

Look at the live feed. See what rhythm your patient is in right now.
Look at events. The computer typically will flag preset rhythms based on an algorithm. It has a high sensitivity so it often flags things that aren’t real arrhythmias. So you have to open each one to evaluate them. When in doubt print out the telemetry strip to have with you to review with your attending physician
Look at the timing of the events. Did your patient have a run of atrial fibrillation last night? Look at the timing of the arrhythmia and ask your patient if they felt it. Similarly if your patient complains of chest pain or palpitations see if there are any events on tele that correlate with that timing.

6. Confirm with an ECG

Tele is great but sometimes it isn’t all that accurate. Always get a confirmatory ECG to compare the rhythm in question.

7. Print out the tele strip in question

I once had a patient who had an abnormal arrhythmia in the ICU. Unfortunately by the time we were able to see the patient they got transferred out of the unit to the floor. When this happened their telemetry data didn’t get transferred with them. So whenever you see something abnormal make sure you print it out and get it uploaded into the patient chart so we can see it in the future. This is also why I like to get an ECG to confirm abnormal rhythms so I make sure it gets uploaded to the EMR.

8. Call for help if you need it

This should go without saying but if you are concerned about a rhythm that doesn’t look right then call for help. If you are an intern and aren’t sure what to make of the tele strip then print them out, discuss with your senior, and on rounds. If you area a nurse then print out the strips and speak to the primary team.

9. But first evaluate the patient clinically

I understand that not everyone is a cardiologist but we are all medical professionals. It is not good enough to simply pass the buck and say ‘I called cardiology about it’. For instance, I’ve gotten calls to say “the patient’s heart rate is 40. What do you want to do?’. Well, it depends! Is the patient fast asleep, hemodynamically stable, and has had normal heart rate trends in sinus rhythm all day? Because a heart rate of 40 could simply be vagal tone brought on by sleep. Or is this a patient who just had a right coronary artery myocardial infarction and is now in complete heart block, feeling dizzy, and becoming hypotensive? My point is that one piece of isolated information is more valuable when put in the context of a clinical situation.

Now let’s go over some real life examples

This is the real meat and potatoes of this blog post. The following case presentations are not based on a single patient and are instead a culmination of many common threads I’ve experienced first hand. So let’s pretend you are a first year cardiology fellow and you are called to evaluate the following patients.

Case Number 1: it’s 3am and you are called because a patient is reported to be in ventricular tachycardia (VT) and the primary team wants to confirm if they should use 100J or 200J for the synchronized cardioversion. They send you a picture of the tele strip, below, while you’re walking to evaluate the patient. What do you tell them to do?

You can tell them to let you and the patient go back to sleep! Here’s why: on the telemetry strip you can see 3 rhythms strips. I labeled them 1, 2, and 3 in red, below. Strip number 1 on the top looks scary. It could be VT! But at first glance it doesn’t look quite right.

Now let’s just jump down to lead number 3 on the bottom. If you saw this lead all on it’s own you would never think “this is VT”. You can see clear cut narrow QRS-complexes. Now go back and look again at the blue circles.

Notice how the narrow QRS-complexes in the bottom lead are also present in the middle lead. Those are pretty easy to march out. The tough part is noticing that they are also present in the top lead. This brings us to our first major learning point. You cannot have an abnormal rhythm in one lead and a normal rhythm in another. If you have VT it should be present in every lead.

So what’s the above diagnosis? It’s tough to make out the underlying rhythm. It could be atrial flutter or just sinus rhythm with prominent T-waves. In the end however it is definitely not VT. The top lead is likely just interference!

Let’s drive this point home and look at another tele strip. Now that you are an expert at figuring out if it’s VT or just interference take a look at this one below.

This is another example where it can easily be mistaken for VT. But look smack dab in the middle at lead III. You can clearly see a regular rhythm with narrow QRS-complexes. You can also see narrow spikes in other leads that correlate with the timing of those sinus beats. The other leads simply have interference.

Now let’s take a look at another tele strip. What’s the rhythm?

In the above tele strip you can clearly see that there are 5 narrow QRS-complexes followed by 7 wide QRS-complexes. This is finally an example of non-sustained ventricular tachycardia (NSVT). In this tele strip the wide QRS-complexes are found in all 3 leads.

Ventricular tachycardia is a wide QRS-complex originating from the ventricle. It is considered non-sustained ventricular tachycardia (NSVT) when it lasts for ≥3 beats but for ≤30 seconds. The 30 second timing is kind of an arbitrary man made classification. But generally if the VT lasts longer than 30 seconds it is classified as sustained-VT. Sustained VT can be deadly because it can deteriorate into ventricular fibrillation (VF) which can be fatal.

To finish out this lesson lets take a look at a 12 lead ECG, below. This is an example of sustained VT.

Diagnosing and differentiating VT from atrial fibrillation with aberrancy is outside the scope of this post but I really like this Life In The Fast Lane blog post on this topic if you’re looking for more information.

Case number 2: you are consulted for ‘runs of sinus tachycardia’. What do you do?

Well first off (*using sassy cardiology fellow attitude*) tell them to try and figure out what the actual rhythm is first and then have them call you back . Okay okay, just kidding..kind of. Let’s dive into why you can’t have a ‘run of sinus tachycardia’.

First off, what should every primary team have done first before calling cardiology about actual sinus tach? The basic work up includes addressing underlying reasons for a patient to be tachycardic. This includes:

Dehydration
Acute anemia
Pain
Fever
Hyper/hypothyroidism
Holding a patient’s beta blocker

Fever tangent: What is Liebermeister’s rule?
Liebermeister’s rule is the appropriate increase in heart rate in response to a fever. In general for every degree abvoe 100F the heart rate should increase by about 10. So a fever of 101 can cause a heart rate of 110. A fever of 102 can cause a heart rate of 120, etc.
Conversely, what is the unusual diagnostic association of fever with bradycardia and what can it indicate? It is known as Faget sign. Faget sign can be seen with intracellular bacterial infections like legionella or mycoplasma pneumoniae as well as many other infections including yellow fever, typhoid fever, tularemia, brucellosis, and Colorado tick fever.

Now let’s say you did all of the above and still can’t figure out wyh on tele you are seeing runs of a fast heart rate. Sometimes looking at the graphic trend can help differentiate different rhythms.

First just think about what your normal heart rate does while in sinus rhythm. Throughout the day if you get up and move around your heart rate increases gradually to accommodate for increased cardiac output requirements. Think about when you walk up a flight of stairs or two. Your heart rate increases slowly. It doesn’t suddenly jump from 60 beats per minute to 150. It slowly climbs up to 65, then 70, then 75, then 80 and so on. Then in recovery after you finish climbing the stairs your heart rate similarly will slowly trend down and decrease slowly from 150 to 145 to 140 and so on. Below is an example of a patient who is in normal sinus rhythm without any arrhythmias.

The above graphic trend is for a 24-hour period. So the small spikes that you see are actually happening over a longer period of time. If we were to zoom in you would see a gradual upslope and then gradual down slope.

Now don’t get fooled. This can also happen in atrial fibrillation. Patient’s can be rate controlled pretty well and have gradual increases in their graphic trends. So just because the graphic trend is gradual it does not mean that it is sinus rhythm. Don’t forget the rules of telemetry. Get an ECG or check the rhythm yourself to figure out what you are dealing with.

Now our patient in question was having ‘runs’ of tachycardia, as seen below.

Above is the graphic trend over an 8 hour period. These bursts of fast heart rhythms are starting SUDDENLY and stopping SUDDENLY. This should not happen in sinus rhythm and indicates that you are likely dealing with some type of abnormal heart rhythm. Arrhythmias that can commonly do this include atrial flutter, atrial fibrillation, and atrial tachycardia.

The learning point here is that the graphic trend can be used to help guide your diagnosis. You cannot solely rely on the graphic trend to make a final diagnosis. You still have to go inside the event strip and FD, or full disclosure, strip in order to figure out what rhythm you are dealing with. When in doubt, print it out! And then call your friendly neighborhood cardiology fellow for some help to figure it out together.

Overnight I got called again abotu this patient’s heart rhythm. The primary team thought it was an SVT so they used adenosine to break the rhythm. Below is what they saw (sorry for blurry image).

In the above image the patient was going in a fast rhythm and adenosine was administered. Adenosine slows AV-nodal conduction. So all that it does it stops the atria from communicating with the ventricle. It does not necessarily stop whatever rhythm is happening inside the atria. In the above strip you can see that after the 5th narrow QRS-complex there is long pause until the next QRS-complex comes in. During that extended time period you can still see about 8 P-waves. This is highly suggestive of atrial tachycardia and is the first thing that comes to my mind when a patient is having ‘runs of sinus tachycardia’.

Atrial tachycardia can look like sinus rhythm, suddenly start, and suddenly stop. Again the full treatment of atrial tachycardia is outside the scope of this blog post but if you want to read more about it I like this LITFL blog post on atrial tachycardia.

Lastly, let’s take a look at another graphic trend, below.

Notice how this rhythm also suddenly goes fast and then suddenly goes slower. This is indicative of an underlying arrhythmia. I would be impressed if someone called me with a consult with this information at hand for assistance in rhythm identification. This is some ‘upper level senior resident who is interested in cardiology’ level of knowledge!

Again, graphic trends can be a valuable tool to help guide your ECG diagnosis but always get a 12 lead to confirm! And if rhythms and ECG’s are still tough for you then don’t worry because I still get them wrong at times. Medicine requires lifelong learning so use every one of your patient’s ECG’s as practice!

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