| Variable | Description |
| subject_id | An identifier for the subject which aligns across the MIMIC-IV database |
| study_id | An identifier for the study which the diagnostic ECG is associated with |
| cart_id | An identifier specific to the ECG cart used to collect the diagnostic ECG waveform |
| ecg_time | The date that the diagnostic ECG was collected on |
| report_# | A text based cardiology report generated by the ECG machine. A variable number of report #'s are expected and can be separated by blank rows. |
| bandwidth | The bandwidth of the ECG machine |
| filtering | An indicator for the filter setting |
| rr_interval | Time between successive R-waves (msec) |
| p_onset | Time at the onset of the P-wave (msec) |
| p_end | Time at the end of the P-wave (msec) |
| qrs_onset | Time at the beginning of the QRS complex (msec) |
| qrs_end | Time at the end of the QRS complex (msec) |
| t_end | Time at the end of the T-wave (msec) |
| p_axis | The electrical axis of the P-wave (degrees) |
| qrs_axis | The electrical axis of the QRS complex (degrees) |
| t_axis | The electrical axis of the T-wave (degrees) |