Is It ESP?

Wouldn’t it be great to be able to predict the future?

Does foreseeing the future really take Electrophysiology Super Powers (ESP) or is it simply just being attentive and watching the subtle details?

You don’t have to be the Mentalist for powers of perception. We all have this characteristic, but we just don’t always use it to our advantage. The electrophysiology study starts long before the initial testing begins, often before the patient is even on the procedural table. To tap into your superpowers, begin by reviewing the patient’s history and any ECGs in their chart. This may give you hints on what type of tachycardia you may find…there is so much to explore here, I will save it for another post.

Today, the form of ESP that I am discussing is when a skilled EP tech can call out a concealed left-sided accessory pathway before any testing has begun. This is a sure-fire way to let the physician know that you not only understand electrophysiology, but you are paying attention and actively participating. This simple move will set you apart from others.

Think back to what we have discussed in Understanding EP: A Comprehensive Approach if you have already had the opportunity to read and study the material. This helpful information may be found in the AVRT section, but it actually starts back with our knowledge of retrograde pacing. When you are pacing the ventricle, what should you be thinking about or watching?

Simple… you are watching for VA block, right?

There is far more to it than whether the ventricular stimulus traveled to the atrium. First, when we are pacing the ventricle we need to observe if we are capturing the tissue. If local tissue is captured, we then look to whether it traveled retrogradely from the ventricle to the atrium. This will be seen with a V followed by an A on the electrogram.

Let’s take this one step further. How did it travel to the atrium? Was the conduction pattern concentric or eccentric? Remember, there is only one pathway from the ventricle to the atrium (and vice versa) in a normal heart – through the bundle of His. However, we are not always working on “normal” hearts. In a patient with an accessory pathway, there is an additional connection in which conduction may travel. If the activation pattern is concentric or midline it does not rule out an accessory pathway, but just that it is not observed at that time. This could be because of location, pacing rate, or various other factors. For those newer to EP, concentric or midline activation is the pattern in which the earliest atrial event is on the His channel followed by proximal to distal CS. If the activation is eccentric in which CS distal is early followed later by CS proximal and His, this is a tell-tale sign of a left-sided pathway.

The trick is when this eccentric activation is observed without pacing. If the CS is in position and there is a spontaneous PVC or ectopy from placing the RV catheter, this eccentric retrograde conduction may be observed. BAM! You just called a left-sided pathway before the study even began. Collect kudos from the team and respect from the physician while you begin pulling the left-sided equipment. Not only does your proactivity show your heedfulness, but it also helps cut down on procedural time.

Start showing off your ESP (Electrophysiology Super Power) today, it only takes attentiveness and your growing EP knowledge. What have you got to lose?

April Felton

This week’s EP question:

This accessory pathway location is associated with the highest risk of heart block during ablation.

1. Anteroseptal
2. Posteroseptal
3. Right Free Wall
4. Left Lateral