Why is the QRS complex seen on V6 positive?

Why is the QRS complex seen on V6 positive?

• A. The ventricles repolarize and become negatively charged
• B. Positive charge moves towards the V6 lead on the patient's chest
• C. The QRS complex is always positive in all leads
• D. Heart rate is always elevated during QRS presence

Answer: (B)

The positivity of the QRS complex in lead V6 is primarily due to the orientation of the heart's electrical activity in relation to that lead. Specifically, lead V6 is positioned on the left side of the chest and is directed towards the left ventricle, which is the most muscular part of the heart. During ventricular depolarization, the electrical impulse travels through the ventricles, causing them to contract. The direction of this electrical activity generally moves from the atria (where depolarization begins) towards the left ventricle.

When the wave of depolarization moves towards the V6 lead, it generates a positive deflection on the EKG tracing. In essence, the lead captures the electric current moving in a direction that is aligned with its placement, resulting in a positive QRS complex.

This principle of lead placement and the direction of electrical activity is crucial in understanding EKG interpretation, as it determines if the deflections will appear positive or negative based on where they are measured in relation to the heart’s electrical axis. Thus, the relationship between the lead position and the direction of the electrical impulse is the reason the QRS complex appears positive in lead V6.