How is a bipolar lead best defined?

• A. Includes leads A and B
• B. Includes leads I, II, and III
• C. Includes only lead I
• D. Is a unipolar lead configuration

Answer: (B)

A bipolar lead is best defined as one that includes leads I, II, and III. In electrocardiography (ECG), these leads are derived from pairs of electrodes measuring the electrical activity of the heart across different angles. Each of these leads represents the potential difference between two electrodes placed on the body, allowing for a comprehensive view of the heart's electrical activity.

Lead I measures the voltage between the right arm and left arm, lead II measures the voltage between the right arm and left leg, and lead III measures the voltage between the left arm and left leg. By utilizing more than one lead, the bipolar configuration captures a broader picture of the heart's electrical activity compared to a unipolar lead configuration, which would only use a single reference point.

This understanding is essential in telemetry and cardiology, as it informs the monitoring and diagnosis of potential cardiac issues.