Abstract: Heart rate is, among the many vital signs (respiration rate, blood oxygen saturation, arterial blood pressure, etc.), one of the most commonly measured and monitored. Whatever will be the sensing principle or the monitoring method used, data referred to the heart rate can be considered the primary vital sign information which is needed on a patient approach in both emergency and clinical situations. Heart rate data are used to measure anomalous rate or irregular pulse rate (arrhythmias) or heart block. The post-processing of the data can be used to verify trends or single events, providing precious elements to the patient diagnosis. Heart-rate variability (HRV) can be performed on recorded data in order to have an objective measure of eventual cardiac abnormalities (irregular beat-to-beat time is a prognostic factor for atrial fibrillation (Gorgas, 2004). Low HRV is also a known prognostic marker for several cardiovascular diseases. Other possible use of the heart rate data are related to the analysis of the circadian rhythm (sleep), temperature regulation, cardiac sympathetic nervous activity and synchronization with respiration rate. Since the past centuries, observation of the electrophysiologic effects related to the heart beats are reported. In 1842, Carlo Matteucci, Professor of Physics at the University of Pisa, shows that an electric current accompanies each heart beat. In 1902 Einthoven publishes (Einthoven, 1902) the first electrocardiogram recorded on a string galvanometer, opening the way to the electrocardiography (ECG) era which is still, nowadays, the primary heart rate monitoring procedure. To date, an enormous series of procedures, methods and devices for ECG monitoring are available on the market (Gorgels PM, 2007; Webster, 1988). The majority of these contributions are based on the need to place some electrodes on standard positions on the body surface (i.e. Einthoven’s triangle), as depicted in fig. 1. ECG measurements can be divided into two types according to where electrodes are attached or fixed. The first type involves measurements with conventional ”fixed-on-body” electrodes such as Ag–AgCl electrodes, and the other involves measurements using electrodes installed on appliances or furniture. Even if fixed-on-body electrodes (fig. 2) are reliable and give good signal quality, they are inconvenient and inadequate for long-term, everyday measurements. Moreover the presence of cables (one for each of the electrodes placed) can considerably limit the patient mobility and comfort, forcing him to maintain the initial position (supine) for all the monitoring period of time or limiting his/her movements because of the cables length.”