Electrocardiography (ECG)
A non-invasive diagnostic technique recording the spatial bioelectric potential changes produced by heart muscle depolarization and repolarization.
Governing formula
Cardiac Dipole Vector P(t), Einthoven's Triangle Lead Vectors
SI unit
mV (Amplitude ~1 mV) & bpm (Heart Rate)
In depth
Records surface body potentials generated by the spreading cardiac electrical wavefront using 12-lead electrode configurations. Identifies P-wave (atrial depolarization), QRS-complex (ventricular depolarization), and T-wave (ventricular repolarization).
Examples in the real world
12-lead ECGs detecting ST-segment elevation indicating acute myocardial infarction (heart attack).