Understanding the precordial leads and how they align with the heart is critical to understanding the EKG. First let's remember how the heart is located in the chest. Note that it sits flat above the diaphragm on the left side of the chest, and is pointed slightly to the left. This is important in understanding how the precordial leads correlate to the actual heart anatomy. We see below the precordial leads in their relationship to the heart and chest anatomy.V1-V2 are over the right ventricle, while V4-V6 primarily are over the left ventricle. V3 is a transitional lead, and is approximately over the intraventricular septum, so it covers some of both ventricles. Remember that the bulk of the left ventricle is posterior, so feel free to create a V7 and V8 to get more information of the left ventricle.
Click here to view the Precordial Leads in 3D
