EKG help

The heart is a muscle formed in a way that allows it to act as a pump for blood, when the heart contracts under command from an electrical stimulus in the electroconduction system.
The heart pumps blood when the muscle cells making up the heart wall contract, generating their action potential. This potential creates electrical currents that spread from the heart throughout the body. The spreding electrical currents create differences in electrical potential between various locations in the body, and these potentials can be detected and recorded though surface electrodes attached to the skin. The waveform produced by these biopotentials is called the eletrocardiogram ECG that is a written record (Graph) of the cardiac leectrical potential waveform.

Using an EKG allows doctors to measure the relative voltage of these impulses at various positions in the heart. Electrocardiograms are possible because the body is a good conductor of electricity. When an electrical potential is generated in a section of the heart, an electrical current is conducted to the body surface in a specific area. Electrodes attached the body in these areas enable the measurement of these currents. On the handheld EKG machine, when your thumbs are in contact with the dry electrodes, the palm-sized device is able to trace and record the micro-current your heart generates during heartbeats, generating the related heart function parameters (PR, QRS, ST).