Portable electrocardiograph machine with trolley and accessories

Portable electrocardiograph machine, all-mains model, on wheeled trolley, with accessories, by the Cambridge Instrument Co. Ltd., 1934

Electrocardiographs (ECG) detect heart rhythms by measuring electrical activity. ECGs can detect heart problems such as artery disease, enlarged hearts and abnormal rhythms. The first commercial ECG machine was developed by the Cambridge Scientific Instrument Company in 1908. An electrocardiogram is the visible result produced by the electrocardiograph.