A PVC apex-to-base yields what in the inferior leads?

• A. Positive in inferior leads
• B. Negative in inferior leads
• C. No change in inferior leads
• D. Biphasic in inferior leads

Answer: (B)

When thinking about ECG deflections, focus on the direction the ventricular activation wavefront travels and how that direction projects onto each lead’s view.

A PVC that starts at the apex and propagates toward the base sends depolarization upward. The inferior leads (which face the heart from below) will see a wave moving away from them, resulting in a negative QRS deflection in those leads. That’s why the inferior leads become negative with this apex-to-base activation.

If the impulse traveled from base to apex, the vector would point toward the inferior leads, producing positive QRS deflections there. So the negative inferior leads indicate a superior-axis activation pattern, consistent with apex-to-base propagation.