I'm studying current of injuries and the diastolic current theory is explained as such:
The ECG machine is programmed to keep the T-P segment at baseline with everything else on the strip moved up or down relative to that. If the T-P segment is depressed, the ECG machine will raise it back up to baseline and concurrently raise the rest of the tracing an equal amount. Thus, instead of seeing actual T-P depression, you will think you are seeing ST elevation.
However in Guyton Hall Physiology under the subheading "Use of the J point in plotting axis of injury potential" it is stated the line passing through the J point is taken as the zero voltage level to which injury current is compared.
I am confused, does the J point represent the baseline or is it the TP segment, or instead do we specifically use the J point as a baseline while examining the direction of only the current of injury?