Unipolar cardiac leads between history and science

The surface electrocardiography (ECG) uses a virtual reference point to measure the potential of chest electrodes. This reference potential is known as Wilson central terminal (WCT) and is assumed negligible (near zero) in amplitude. Consequently, the precordial leads have been named as the unipolar leads. Although this assumption was found incorrect immediate after this reference potential was introduced, it was difficult to measure its real amplitude. We recently introduced a 15-lead electrocardiography device that can record the traditional ECG leads in combination with the raw potential of limbs and chest electrodes directly referred to the circuit grounding. Consequently, we are able to record the potential of the raw chest electrodes, which we named as true unipolar chest leads. The aim of this study is to have a clear understanding of the WCT potential and its influence on the chest leads. Our records show that the true unipolar leads may be more sensitive for detecting cardiac diseases in the left anterior descending coronary artery in patients with non-ST elevation reported on chest leads.