Methods of measuring features of a digitally generated waveform include communicating patient data to a device that is remote from a source of the patient data, generating the waveform on a touch-screen display of the device, and measuring along an axis of the waveform. The measuring includes generating a first point corresponding to the waveform based on contact with the touch-screen display, generating a second point corresponding to the waveform based on contact with the touch-screen display, automatically measuring a distance between the first point and the second point along the axis upon generation of the second point, and displaying a value corresponding to the distance on the touch-screen display.