The ECG paper speed is ordinarily 25 mm/sec. As a result, each 1 mm (small) horizontal box corresponds to 0.04 second (40 ms), with heavier lines forming larger boxes that include five small boxes and hence represent 0.20 sec (200 ms) intervals.
Z codes are a special group of codes provided in ICD-10-CM for the reporting of factors influencing health status and contact with the health services.
