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Do you have some "Tricks of the Trade" to share with other ECG instructors?

Fri, 10/26/2012 - 22:30 -- Dawn

Our expert today is Darlene Hutton, RN, BScN, MSN

She has worked in CCU, ICU, PACU, and Emergency as a bedside nurse, educator, and manager. She is currently working as a Clinical Research Manager at Rouge Valley Metabolic Research Associates in Toronto. Darlene also is an Educational Consultant providing workshops, seminars, and conferences on such topics as ECG Interpretation, Dysrhythmia Interpretation, Acute Coronary Syndromes and Cardiology Drugs. She is also an ACLS Course Director and runs courses throughout the province. Her company, QRS Educational Services, founded 18 years ago, provides education to nurses and other health care professionals throughout Canada. She is also the Department Head for Emergency Preparedness in the O.R. in the American College of Plastic Surgical Nursing journal. 

Darlene@qrseducation.com 

(905) 706-3301 

www.qrs-education.com 

www.facebook.com/qrs.educationservices

 

Answer:

I sure do have lots of tricks to help me retain what I learn and I pass these tricks to those that I spend time teaching. The reason I have developed these tricks is because I have found that I best learn from visual demonstration and KISS principles, not only that; but, if we make things too complicated from the get-go, people won't want to learn the concepts.

 

Trick #1: Using the RIRI approach to ECG assessment. The acronym RIRI reminds us to check Rate, Intervals, Rhythm, and Ischemia/Infarction. We need a fast, reliable method to systematically look at and ECG. I can't tell you how many times people rush to checking out the ST segment elevation which is plainly there and overlook the fact that the patient is in a bundle branch block or in a 3rd degree AV block. I have established this method for assessment over 15 years ago, teach is regularly, and use it myself. If you want to add a diminsion to the assessment, you can always throw in axis determination right when doing the Intervals; specifically the QRS interval.

 

 

Trick #2: Bundle branch blocks: Goodness, how this has gotten complicated. It really isn't. If there's a P wave in front of a wide QRS complex, that's a bundle branch block. Otherwise, if there is no P wave with a wide QRS complex, it would be a ventricular rhythm. Here comes the fun part, when you've established there is a bundle branch block, take a look at V1 on the 12 Lead ECG. If V1 is "upright", you have a "right" bundle branch block. If V1 is "down low", you have a "left" bundle branch block. There are many other quick, neat ways that also work, but it is difficult to explain without physically showing you. The most important part of determining a bundle branch block is knowing that a "left" will often mask an acute coronary syndrome; specifically an MI. Right bundle branch blocks don't tend to mask MIs nearly as much. So, forget the misconception about "bunny rabbit ears", or the confusion of "slurred S waves in the lateral leads". Keep it simple and you'll remember forever. Upright = right, Down Low = Left.

 

 

Trick #3: Axis is another area that has been so complicated and unnecessarily so. The first thing I share with my students is what axis is and the various non-critical causes of an abnormal axis: pregnancy, obesity, hypertrophy, pulmonary stenosis, neonates, pulmonary hypertension, previous MIs, and others. These are all conditions that do not occur overnight and do not cause concern for an abnormal axis. The second part that I share when teaching axis, is the "how". You need a simple, uncomplicated method to teach and remember axis. I was first taught, and still remember the 7 steps along with plotting, to determine the exact degree of axis. It dawned on me quite a few years after, that the cardiologists I worked with simply reported "axis normal, right, left, extreme". Why were we, perhaps still are, taught a method that few people retain? So, here's the simple, way I teach it for better retention: 

 

 

 

Normal:

 

Extreme:

 

Left:

 

Right:

 
               

Lead I

 

 

 

 
               

Lead II

 

 

 

 
               

 

When looking at axis, look at Leads I and II

 

Normal="2 thumbs up", both I and II's QRS are upright

 

Extreme="2 thumbs down", both I and IIs' QRS are negative

 

Left = "knees apart", that's a lewd way to sit

 

Right= "knees together", that's the "right" was to sit.

 

For those who want to understand axis, they need to understand when an abnormal axis is a concern. In my opinion, the cardiac patient who has just had an anterior MI with a right bundle branch block is the patient you need to be supervigilant on looking at their axis. Why? Well, if their axis suddenly changes in this situation, it's likely because that patient has just blocked off the last remaining electrical circuit in their ventricles and may very likely develop syncope and significant bradyarrhythmias.

If you're going to teach axis, you need to understand it well yourself and you need to understand hemi-blocks and bifascicular blocks, and teach these concepts in a non-complicated manner.

 

Hope these tricks help.

 

 

 

 

 

 

Comments

Submitted by VinceD on

I think Taigman first coined the "turn-signal" mnemonic to determine which BBB you're looking at based on V1. When you're turning right in your car, you flip your turn signal up, so an upright QRS is right-BBB. Going left, and you flip the lever down, so a downward QRS is left-BBB.

I never came across it when I was starting out, but I have to imagine it's an immensly useful memory aid for beginners.

 

ekgpress's picture
Submitted by ekgpress on

There is a lot of wisdom in Darlene's "tricks of the trade" comments. What will be helpful as a memory aid I believe will be modified depending on the level of the learner. When first starting out - ECG Interpretation can be overwhelming. Use of "Tricks" #1, 2, & 3 above per Darlene's excellent post can be quickly learned and serve to advance the beginner in rapid fashion.

Even after looking at a few million ECGs over recent decades - I still like and use "tricks" - both to teach others, as well as to help myself remember. I'll offer below a look at Darlene's Basic Tricks modified for the more advanced user.

#1) Rate-Rhythm-Intervals-Axis-Hypertrophy-Infarct (= QRST Changes). At the next level- the interpreter should add to RIRI estimation of - axis - chamber enlargement - and not only ST-T wave changes - but presence of Q waves and R wave progression.

  • Axis (See below) becomes important when assessing for the hemiblocks and for RVH.
  • Recognition of atrial and ventricular enlargement may explain axis deviation and ST-T abnormalities that are not due to ischemia/infarction.
  • Detection of the Tall R Wave in lead V1 is a subtle but important finding that is easily missed unless specifically looked for - so using "Q-R-S-T Changes" as the memory aid when assessing for ischemia avoids that pitfall.

#2) In addition to RBBB and LBBB - there is IVCD (= IntraVentricular Conduction Delay) - which simply stated is a QRS widening conduction defect not fulfilling criteria for either RBBB or LBBB. Use of 3 key leads (= leads I,V1,V6) allows quick and easy determination of whether sinus rhythm with QRS widening (that is not due to WPW) is due to: i) LBBB; ii) RBBB; or iii) neither = IVCD.

  • In addition to being up in V1, RBBB should manifest wide terminal S waves in leads I and V6.
  • In addition to being down in V1 - LBBB should manifest an upright R wave in leads I and V6.
  • If the conduction defect does fit those criteria in each of the 3 key leads - then you have IVCD.

#3) Darlene is RIGHT ON that axis has become so complicated, and unnecessarily so. You can easily estimate the number of degrees in the axis by looking at lead I (which is at 0 degrees) and lead aVF (which is at +90 degrees). If both are about equally positive - then you are close to +45 degrees. If aVF is a lot more positive than lead I - then you are probably between +60-to-70-to-80 degrees or so. There is NO need to be exact - If you are anywhere within 30 degrees, you are fine.

  • IF leads I and F are both positive = Normal axis
  • IF lead I is positive; F is negative = LAD (left axis deviation)
  • IF lead I is negative; F is positive = RAD (right axis deviation)
  • IF leads I and F are both negative = indeterminate axis (= extreme axis deviation)

At the next level you'll want to know:
i) Is there LAHB (left anterior hemiblock) ? - most easily defined by an LAD in which lead II is more negative than positive.
ii) Is there RVH? - strongly suggested by RAD, esp. if patient has a history of pulmonary disease and RAE (right atrial enlargement) on ECG.
iii) Is the axis indeterminate? - commonly seen in patients with COPD.

To the above suggestions could be added another (and then one more after that) "layer" of tricks for more advanced providers. We are all learning (and we all use "tricks" ). Darlene's tricks offer "biggest bang for buck" to move the beginner onward in their interpretation. Many more helpful hints for interpretation regularly appear on the ECG Guru. Feel free to ADD to what Darlene and I have suggested.

Ken Grauer, MD  www.kg-ekgpress.com   ekgpress@mac.com