Another popular monitoring is called ____ ___ ____. It is a bipolar lead that can be useful in differentiating rhythms with broad QRS complexes.

• A. Modified Chest Left
• B. Lead II
• C. Standard Limb Leads
• D. Precordial Leads

Answer: (A)

A lead that helps differentiate broad QRS tachycardias works best when it provides a clear view of ventricular activation. The Modified Chest Left lead is a bipolar chest lead, using two electrodes on the left chest to create a specific viewing angle of the heart’s electrical activity. Because it sits over the left chest, it captures ventricular depolarization more directly, making differences in QRS morphology between ventricular tachycardia and a supraventricular tachycardia with aberrancy easier to see. This orientation can make wide QRS complexes appear distinctly different from those seen in other rhythm types, which is why this bipolar chest lead is particularly useful in differentiation.

Standard limb leads (like Lead II) are valuable for rhythm monitoring but aren’t chest-based bipolar leads, and precordial leads are unipolar configurations. That combination makes the modified chest left lead the best choice for this specific purpose.