ECG is a relatively easy thing to measure, so that single axis they measure is quite accurate. But the conclusions one can make from that is limited (you basica

ECG is a relatively easy thing to measure, so that single axis they measure is quite accurate. But the conclusions one can make from that is limited (you basically take a video from a single point). Doctors use 12 axes instead to get a real-time, 3D vector of the heart.