Certified Rhythm Analysis Technician (CRAT) Practice Exam 2026 – All-in-One Study Guide for Exam Success!

Standard limb leads, when positioned appropriately on a patient, do indeed create what is known as the Einthoven triangle. These leads are classified as bipolar leads because they measure the electrical potential difference between two electrodes. In a bipolar lead system, one electrode serves as a positive (positive pole) and the other as a negative (negative pole).

The standard limb leads (lead I, II, and III) take readings from two of the limb electrodes each, with one serving as the positive and the other as the negative for each lead. This configuration is crucial because it allows for the capture of electrical activity from the heart in different perspectives, which is essential for accurately interpreting the cardiac rhythm and detecting any abnormalities.

The distinction of being bipolar is important especially when comparing to other lead types, such as unipolar leads, which use a single positive electrode and reference the potential to a neutral point. In summary, standard limb leads forming the Einthoven triangle being recognized as bipolar leads indicates that they rely on the relative voltages between two electrodes to produce meaningful electrocardiographic readings.