How to learn to read EKGs

I’ve had several people ask me about learning to read EKGs.  In my opinion, there are two things that you must master to effectively interpret EKGs.

First, and most obviously, you must understand the conduction system of the heart, the electrical concepts behind obtaining an EKG, and the normal EKG waveform and intervals.  I think of this as the “mechanical” part of reading an EKG, where the knowledge is well defined and is simply a matter of learning.

Second, and not so obviously, you have to be able to analyze a real world EKG by extracting the important information and ignoring the distractions.  An EKG is like a painting by Salvador Dali, it probably contains more information than you need to know.

The Hallucinogenic Toreador (1968–1970) by Salvador Dalí

What is important information?  Things that you need to know for your specific requirements: rate, rhythm, ST segment changes, signs of electrolyte imbalances or drug overdoses.  Things that are not important depend on your situation at the time – if you are working in a busy ER, and a patient comes in with massive ST segment changes, you probably don’t need to worry about the low level noise seen on the EKG (was the patient shivering?, were the lead wires moving?, is there a loose connection on the grounding wire?), you just need to get the patient to the cath lab NOW.

The only good way to learn how to pull out the information you require from the background noise is by reviewing EKGs.  Lots and lots of EKGs.

For the first part of learning EKGs, the mechanical section, I recommend a book by Brenda Beasley, Understanding EKGs: A Practical Approach (3rd Edition).  If you read the reviews of Beasley’s book, one common complaint is that it is too simplistic, and that it doesn’t have enough review strips.  That isn’t actually a bad thing, because this book is one of the best at teaching you the mechanics of an EKG, and we can leave the information extraction experience to a different book.

For the second half of learning EKGs, we turn to a book by Jane Huff, ECG Workout: Exercises in Arrhythmia Interpretation (Huff, ECG Workout).  This is a book of over 600 EKG strips, with all the messiness of the real world.  Here you will find not just important rhythms, but also pens that smear ink, patients that are shivering, and all the other gems found during the practice of medicine.  Some of the reviews mention that the Huff workbook it too advanced, that it is too hard for beginners.  But that’s OK, because we already got the basics from Barbara Huff’s book.

When you are evaluating EKGs, you will need a good set of calipers that won’t slip when you are making measurements.  These Prestige calipers from Amazon will work well for getting started: Prestige EKG Caliper.

Interpreting EKGs can be fun, just like reading a book, where the lines on the page tell a story to those that can read the words.  Let me know of any interesting rhythms that you run across!