A device intended to be used by a healthcare professional in a clinical setting to record the electrical activity of the heart and display it in the form of a graph, to assist a physician in assessing electrical cardiac physiology [electrocardiography (ECG)]. It is designed to record the electrical signal from only one configuration of electrodes (ECG-leads) at a time (single-channel) but may otherwise include a variety of additional features [e.g., interpretive software, data telemetry, display screen]; electrodes may be included. It is intended to be used by a healthcare professional in a clinical setting.