Abstract: A system for allowing interactive time measurement and comparison of events and indication of heart rate intervals is disclosed. A part of vertical lines, an anchor bar and a movable or measurement bar, are displayed on a graphic display along with the signal to be analyzed. The bars can be moved relative to each other and the time between the two bars is indicated above a horizontal line connecting the bars. The bars may be locked in place and moved to a different portion of the gathered signals to allow precise comparison. Additionally, a signal channel is monitored for maximum, minimum and baseline values. These values are used to determine a maximum deviation from the baseline and from that deviation an event trigger level is developed. The time between two signal portions greater than the trigger level is measured and displayed as the heart rate.