In electrocardiography, what does lead aVL record?

• A. Activity across the heart to the left shoulder
• B. Activity to the right shoulder
• C. Activity from left leg to right arm
• D. Activity between the center of heart and chest wall

Answer: (A)

Lead aVL records the electrical activity of the heart primarily in the frontal plane, specifically focusing on the left side of the heart as viewed from the left shoulder. It is classified as an augmented limb lead and is positioned to measure the potential difference between the left arm and a composite reference point derived from the other limbs. By capturing this electrical activity directed toward the left shoulder, lead aVL provides valuable information about the heart's electrical system, specifically revealing aspects of the left atrium and ventricle's activity as well as potentially indicating issues with the left-sided heart structures. This positioning and perspective help clinicians assess conditions related to left-sided heart function.