So when the heart cell depolarizes, positive ions are let out. Because this propogates down the heart this causes the positive current. I believe what the ekg is measuring is the change in voltage, over time, across a lead. Does that make sense? Sorry, I'm trying to make it make sense!
Ah, I guess I assumed current was flowing. You're right, the leads are simply measuring voltage change. Just to make sure this makes sense then... if a positive current causes an upward deflection on an EKG, the recording terminal must be the positive one, correct?
Given a standard 3-lead ekg where the leads are read as below:
Why does atrial depolarization cause an upward deflection? Assuming the EKG is being read from Lead II, I believe that if the current flowing from the negative terminal at RA (right arm) to the positive terminal at LL (left leg) is...