A cardiograph is a medical device that is used to measure electrical activity in the heart. It is commonly referred to as an electrocardiogram (ECG or EKG), and it is a non-invasive test that is used to evaluate the electrical activity of the heart. It records the heartbeat by measuring the electrical impulses that are generated by the heart muscles and transmitted through the body. These electricalECG) machine. The device works by placing electrodes on a patient's chest, arms, and legs, which then record the electrical pulses produced by the heart. These electrical pulses are used to create a graphical representation of the heart's activity, which can be analyzed by medical professionals to diagnose and monitor various heart conditions and diseases. ECGs are commonly used to detect irregular heartbeats, blockages in the arteries, and other problems with heart function.