You observe a wide QRS complex in lead II. Which lead should you check to evaluate the location of the bundle branch block?
A)Lead I
B)Lead V1
C)Lead III
D)Lead V4

Question

Quizplus · Accepted Answer

Lead V1 is the best lead to evaluate the location of a bundle branch block because it shows the initial deflection of the QRS complex. In a right bundle branch block (RBBB), there is a wide QRS complex and a small initial R wave in lead V1, while in a left bundle branch block (LBBB), there is a wide QRS complex and a broad or notched initial R wave in lead V1.

You Observe a Wide QRS Complex in Lead II