Final answer:
The precordial electrode placed at the fourth intercostal space to the right of the sternum in a 12-lead ECG is V1, important for accurate heart activity readings.
Step-by-step explanation:
The precordial electrode that is located by counting to the fourth intercostal space to the right of the sternum is known as V1. In a 12-lead ECG, six electrodes are placed on the chest to record the heart's electrical activity from different angles. The correct positioning of electrodes is crucial for accurate readings, with V1 being the first of the chest or precordial leads. To locate V1, one must identify the fourth intercostal space at the right margin of the sternum.