An apparatus, comprising: a probe having a plurality of electrodes (32, 33) and sensors; electrical circuitry for receiving data from the electrodes and sensors when the probe is at a location in a heart of a living subject; a memory; a display monitor; a processor connected to the memory and the display monitor and operative for performing the steps of: displaying an electroanatomical map of the heart on the monitor; and during a time interval that does not exceed a duration of a cardiac cycle of the heart, performing the further steps of: reading data from at least one of the electrodes (32, 33) and sensors; performing an algorithm on the data, the algorithm having a plurality of inputs and a result, wherein the data comprises one of the plurality of inputs and the result comprises a transformation of the data; and rendering the result on the monitor to modify the electroanatomical map; wherein the algorithm comprises the steps of: selecting first electrodes from the electrodes wherein the first electrodes are in contact with tissue of the heart; identifying relative motion of the first electrodes with the tissue; selecting second electrodes from the first electrodes, wherein the second electrodes exhibit a predetermined amount of the relative motion; selecting third electrodes from the second electrodes, wherein respective locations of the third electrodes in successive beats have a correlation score below a predetermined threshold; and generating the result from data obtained from the third electrodes. a probe having a plurality of electrodes (32, 33) and sensors; electrical circuitry for receiving data from the electrodes and sensors when the probe is at a location in a heart of a living subject; a memory; a display monitor; a processor connected to the memory and the display monitor and operative for performing the steps of: displaying an electroanatomical map of the heart on the monitor; and during a time interval that does not exceed a duration of a cardiac cycle of the heart, performing the further steps of: reading data from at least one of the electrodes (32, 33) and sensors; performing an algorithm on the data, the algorithm having a plurality of inputs and a result, wherein the data comprises one of the plurality of inputs and the result comprises a transformation of the data; and rendering the result on the monitor to modify the electroanatomical map; displaying an electroanatomical map of the heart on the monitor; and during a time interval that does not exceed a duration of a cardiac cycle of the heart, performing the further steps of: reading data from at least one of the electrodes (32, 33) and sensors; performing an algorithm on the data, the algorithm having a plurality of inputs and a result, wherein the data comprises one of the plurality of inputs and the result comprises a transformation of the data; and rendering the result on the monitor to modify the electroanatomical map; reading data from at least one of the electrodes (32, 33) and sensors; performing an algorithm on the data, the algorithm having a plurality of inputs and a result, wherein the data comprises one of the plurality of inputs and the result comprises a transformation of the data; and rendering the result on the monitor to modify the electroanatomical map; selecting first electrodes from the electrodes wherein the first electrodes are in contact with tissue of the heart; identifying relative motion of the first electrodes with the tissue; selecting second electrodes from the first electrodes, wherein the second electrodes exhibit a predetermined amount of the relative motion; selecting third electrodes from the second electrodes, wherein respective locations of the third electrodes in successive beats have a correlation score below a predetermined threshold; and generating the result from data obtained from the third electrodes.