The 12 Leads of Christmas: aVF

This article is the fifth in our latest series, The 12 Leads of Christmas, where each day we examine a new finding particular to an individual electrocardiographic lead. I dug myself quite a hole on this one as there’s really not much to say about aVF. It’s located midway between leads II and III so any features you see here can usually be seen in one or both of those other leads. There is one trick that we can discuss pertinent to aVF, however… In the second piece of this series examining lead II we discussed the lead II sign of right-arm/right-leg wire swap, why it displays the pattern that it does, and how the lower extremities are essentially equivalent from an electrocardiographic standpoint. I highly suggest reading that short article again before adding this trick to your practice. There’s two keys to why this works: The left leg and right leg are essentially electrically equivalent. The left leg electrode is the only lower extremity electrode that contributes directly to the electrocardiogram. Depending on the particular electrocardiograph machine the right leg electrode can be used to perform common-mode rejection and acts as a ground, but it is not essential and some machines don’t even require the right leg electrode to be attached. So what does that mean? You can swap the left and right leg wires with almost no effect on the resulting electrocardiogram! Well, there will be an effect—and this is why you would even bother doing such...
Source: EMS 12-Lead - Category: Cardiology Authors: Tags: 12-Leads of Christmas Original Articles Vince DiGiulio Source Type: research