Different people will have slightly different EKGs (almost like finger prints). A tall thin person will have a noticeably different EKG than a short round person. People with large and round chests may have "low QRS voltage" due to their large body size. The more tissue there is for the EKG impulse to travel through, the lower the voltage appears on the EKG tracing. A low QRS voltage on an obese person is not unusual, but the computer does not take this into account. If you are a skinny person with a low QRS (pulse for ventricles) voltage, this may be something that the doctor has to review.
Or it could be improper calibration of the equipment or malfunction.
the above is me - there was no panic attack