looking for some cardiac experts

[Guest219794]

Hey cardiac experts. I have been finding that many nurses who use telemetry don't really understand it. This becomes most obvious when I see people placing the preordial electrode in various random spots on the chest. I have been finding myself in a mentoring position lately, and expect this this to increase in the future.

I wrote a draft of an explanation of a couple of issues that I think are frequently misunderstood. If you have the time and the interest, please read it- and pick it apart. I am very thick skinned, and won't be offended. I am particularly concerned about technical errors, but appreciate any feedback.

A lead is the direction that from which we look at the electrical activity in the heart. The electrical activity is usually, but not always, a reflection of what is going on mechanically. By looking at the electrical activity from different angles (or leads), we can surmise what is happening mechanically in different areas of the heart. For example, we might be able to surmise that a particular artery is blocked, which would cause an area of the heart to become necrotic, and stop functioning.

The lead we are most accustomed to looking at is lead II. Electricity in the heart flows predominantly from upper right to lower left. Lead II looks from lower left to upper right, directly at the oncoming electricity, so most of the waveforms are positive, meaning they deflect upward from baseline.

Other than being a commonly used view, there is nothing magical about lead II. It is one of three leads that look at the inferior portion of the heart. Because we are very accustomed to looking at lead II, it is easy for us to notice certain changes from the norm quickly. Other significant occurrences will not show in lead II at all.

To understand telemetry monitoring, you need a basic understanding of the 12 lead EKG. Many units use a five electrode monitoring system. It is commonly called a five lead system. This misnomer contributes to the misunderstanding of cardiac monitoring by telemetry. A five electrode system in any given configuration can look at 7 different leads. In a standard configuration, most 5 electrode system look at leads, II, III, and avf, (inferior heart) I and avl (lateral heart), avr, (nothing- a truly worthless lead) and your choice of V leads.

The most commonly used V leads are V1, V2 (septum), V3, V4, (anterior) V5, V6 (lateral). These are 6 of the leads used in a standard 12 lead EKG. There are other valuable but less common V leads that are sometimes used to monitor the right and posterior portions of the heart. Unfortunately, if you were to monitor V4r, or V9, many nurses would look at you as if you were nuts. Probably write you up. For now, let's just stick to using the more common V leads, 1-6.

As the nurse you decide which V lead to monitor. Your electrode placement will determine which lead you monitor. The positions are the same as on a 12 lead EKG. For example V1: right 4th intercostal space, V2: left 4th intercostal space etc.Despite the fact that you may have seen the brown electrode put in the middle of the chest many times, there is no V1.5.

The next time you see the brown electrode in the middle of a patient's chest, ask whoever put it there which lead they are planning to monitor. You may be told "the V lead" (no such thing) or "it's a ground" (no, it's not).

Your monitoring system probably has a choice of displaying any one or two leads. If it displays two leads, the defaults are probably lead II, and a V lead. Remember, you decide which V lead the system monitors. You can also decide which two leads the system displays.

Deciding which leads to monitor and display depends on pt's condition. There are many factors beyond this discussion. For example, you might have a pt showing some signs of septal ischemia, so you might monitor V1 or V2. You might have a patient with a right bundle branch block, so you would consider a lead that would show a developing left bundle branch block. If two of the three electric pathways are blocked, a pacemaker might be needed.

As the nurse, you also need to know how to choose and switch which leads you monitor. There are some rhythms that look like V-tach in one lead, but are clearly not when examined in another lead

[athena55, BSN, RN]

Hello hherrn;

I am by no means a "cardiac expert" but I have worked telemetry before, in the VA system [and I presently work in a combined ICU] There the telly leads that they (the VA) use are: I, II, III, aVL, aVR, AVF, V, MCL. They use a five lead system.

As you know, telemetry treats "noisy" or corrupt signals by squaring off the wave and dropping it to the bottom, in order to distinguish that situation from the patient's physiological state, which will prevent false alarms from sounding off all the time!

I think it would be a good idea to incorporate Einthoven's triangle when talking about the bipolar limb leads (I, II, III) and the unipolar limb leads (aVR, aVL, aVF). A picture of the horizontal plane (the precordial or chest leads, as mentioned above) and perhaps a quick bit on waveform morphology.....electrical energy going toward a positive electrode will be positive or upright.....might be a wee bit of help...

Does your hospital use the three lead system or five?

I must say though, that if a health care facility uses a three lead system then the leads would be placed as: 1st choice: MCL1, 2nd choice: MCL6, 3rd choice: lead II.

SO when using the modified chest lead (MCL) the positive lead would go on the 4th ICS MCL, the same place as V1 would be on a standard 12 lead EKG, just like you said.

I think it is a matter of teaching, like you stated, which leads you are monitoring and why. But, for example, AACN ECCO phase 1 teaches that when using the MCL the positive lead goes in the position of the corresponding V-lead....So perhaps that's why some people tell you they are monitoring the V-lead?

It is good that you touch on which EKG lead indicates which coronary artery and myocardial area that is involved but I also think it is a good idea that you speak more about the reciprocal changes that one would see in V1-4 and common EKG findings per different syndromes such as: Angina, Unstable Angina, Non-Q wave MI, Q wave MI......things that one will see in the ACS patient on a telemetry unit or CCU. (for example: how does one differentiate LBBB from AMI?)

GOOD JOB!

athena

[richard1980]

Next time that happens just say, "you really don't know how to do your job, huh?" Just kidding...refer them to Dale Dubins Rapid Interpretation of EKG's. Explains it from a physiologic standpoint and makes "memorizing" rhythms and lead obsolete. If they can't get it after that, maybe they just aren't cut out to work with cardiac patients.

[joeyzstj, LPN]

Its funny you bring this up. I just attended a lecture where many examples of this were given. They showed how people place the V lead in say........the V3 spot and still use V1 monitoring on the monitor, or how people place limb leads on the belly of a 400 pound patient instead of the hims and expect it to read the same when the belly moves around. He also showed examples of EKG techs not placing the leads in the correct position and people almost buying a trip to cath lab. Its insane.