Identifying instances of cardioversion while building a position map

A method includes computing a position of an intrabody probe, which includes one or more electrodes and an electromagnetic sensor, within a heart of a subject, based on an induced signal received from the electromagnetic sensor, ascertaining a set of properties of signals passed between the electrodes and multiple reference electrodes located at respective reference positions, based on the set of properties, deriving an estimated position of the probe from a position map that maps multiple sets of properties to respective estimated positions, in response to a distance between the computed position and the estimated position being greater than a predefined threshold, ascertaining whether an electrocardiographic signal from the subject is saturated, and in response to the electrocardiographic signal not being saturated, updating the position map so as to map the set of properties to the computed position. Other embodiments are also described.