Implementations provide methods including actions of processing patient data to generate one or more graphical representations of the patient data, at least one graphical representation of the one or more graphical representations including a waveform, displaying at least one waveform segment of the waveform, and displaying calipers associated with the at least one waveform segment, each caliper being associated with an interval, where displaying the calipers includes, for each caliper: receiving a measurement value of the interval associated with the caliper, determining respective positions of a first handle and a second handle of the caliper based on the measurement, and displaying the first handle and the second handle in the respective positions relative to the at least one waveform segment.