Where is the V3 electrode placed for a 12 lead ECG?

The V3 electrode is placed in the fifth intercostal space at the left side of the sternum, which corresponds to option A. This positioning is crucial for obtaining accurate readings of the heart's electrical activity from the anterior and lateral walls of the heart. The placement allows for optimal contact with the skin and provides a clear view of the electrical signals emanating from the heart.

When correctly positioned, the V3 electrode helps to contribute to the interpretation of various cardiac conditions by providing essential information regarding depolarization and repolarization patterns in the heart muscle. Proper electrode placement is critical to ensure that the ECG readings are reliable and actionable.