Computer-implemented method of handling electrocardiogram data

A computer-implemented method of handling electrocardiogram data having a plurality of magnitude values varying over time and representing a succession of heartbeats, the method comprising:

• the computer displaying the electrocardiogram data on a display;
• wherein the electrocardiogram data includes a plurality of single axis graphs
• the computer categorizing a first zone of the electrocardiogram data including:
• receiving a first user input and identifying a first temporal coordinate of the electrocardiogram data based on the first user input;
• receiving a second user input and identifying a second temporal coordinate of the electrocardiogram data based on a second user input;
• defining the first zone of the electrocardiogram data as extending between the first temporal coordinate and the second temporal coordinate;
• and
• receiving a third user input indicative of a category selected by a user on the computer, the computer assigning the category to the first zone based on the third user input.