Electrocardiogram

The electrocardiogram (EKG) was developed using a string galvanometer to record the heart's electrical potentials. It became a crucial tool in diagnosing heart conditions based on rhythmic electric potentials.
 Willem Einthoven Netherlands 1903 Electrocardiogram

The electrocardiogram (EKG) was developed using a string galvanometer to record the heart's electrical potentials. It became a crucial tool in diagnosing heart conditions based on rhythmic electric potentials.