How many leads are used in a dual-chamber/bipolar pacemaker?

• A. One lead
• B. Two leads
• C. Three leads
• D. Four leads

Answer: (B)

Dual-chamber pacemakers are designed to monitor and pace two cardiac chambers: the atrium and the ventricle. To achieve this, two separate leads are implanted—one in the right atrium and one in the right ventricle. The term bipolar describes the electrode setup on each lead (tip and ring electrodes forming two poles), not the total number of leads. Therefore, a dual-chamber/bipolar pacemaker uses two leads.

A single-lead system paces only one chamber. A three-lead system would typically support additional left-ventricular pacing for resynchronization (CRT), and four leads go beyond the standard dual-chamber configuration.