In the context of an electrocardiogram (ECG), the terms AVR, AVL, and AVF refer to three of the six limb leads that are used to measure the electrical activity of the heart. These leads are part of the standard 12-lead ECG, which is a non-invasive test that records the heart's electrical activity from 12 different angles. AVR (Augmented Voltage Right), AVL (Augmented Voltage Left), and AVF (Augmented Voltage Foot) are unipolar limb leads that are derived from a combination of the bipolar limb leads. They provide different perspectives on the heart's electrical activity and are particularly useful for diagnosing certain conditions such as myocardial infarctions (heart attacks), bundle branch blocks, and other conduction abnormalities. Each lead views the heart from a different angle, and the signals they record are influenced by the position of the electrodes on the body. The AVR lead is positioned to give a positive view of the electrical activity in the right atrium and ventricle, AVL provides a view from the left arm, and AVF from the foot. read more >>

For a routine analysis of the heart's electrical activity an ECG recorded from 12 separate leads is used. A 12-lead ECG consists of three bipolar limb leads (I, II, and III), the unipolar limb leads (AVR, AVL, and AVF), and six unipolar chest leads, also called precordial or V leads, ( , , , , , and ).read more >>