Automated graphical presentation of electrophysiological parameters

#The present invention relates generally to electrophysiological measurements, and particularly to apparatus and methods for automated mapping of electrophysiological parameters.

#An electrophysiological (EP) map of a tissue of a patient is generated by positioning one or more electrodes on a region of the tissue, acquiring an EP signal of the region, and then repeating the process for a different region. EP parameters are extracted from the EP signals in each region of measurement, and then displayed over an image of the tissue.

#Embodiments of the present invention that are described hereinbelow provide improved methods and apparatus for mapping of electrophysiological parameters.

#FIG. 1 is a schematic pictorial illustration of a medical apparatus for mapping an EP parameter in a heart of a patient, in accordance with an embodiment of the present invention;

#FIG. 2 is a flowchart that schematically illustrates a method for automated EP mapping, in accordance with an embodiment of the invention; and

#FIGS. 3A-3C are schematic illustrations of an electro-anatomical map, comprising a 3D map of a chamber of a heart, with a superimposed visual indication of EP parameters during a measurement and after an automatic removal of inconsistent EP parameters, in accordance with an embodiment of the invention.

#Generating an electrophysiological (EP) map of a tissue of a patient involves positioning one or more electrodes on a region of the tissue, acquiring the signal of the region, and then repeating the process for a different region. When small numbers of electrodes are used, this process generates accurate maps of the EP parameters extracted from these signals, since the physician can observe the acquired signals, and only accept “good” signals (as judged by the physician) into the map. A good signal is typically generated only when the electrode is in good contact with the tissue. Using a small number of electrodes has, however, the drawback that the mapping takes a long time.

#For catheters with large numbers of electrodes, the mapping time is reduced, but the accuracy is decreased, since the physician is incapable of properly inspecting all the simultaneously generated signals within the available time. The task of accepting good signals (and rejecting others) may be facilitated by presenting to the physician the analyzed results of the signals, i.e., the values of an EP parameter across the measured region. (For the sake of brevity, “value of an EP parameter” will in the following description be referred to simply as “EP parameter.”) The task may be further facilitated by presenting these values in a graphical form, such as a map of the values. However, the physician is still required to use his/her subjective judgement in accepting or rejecting the analyzed results, with an inherent variability in the acceptance due to subjectivity. Moreover, requiring the physician to judge the quality of these results will further tax his/her time and attention during the mapping procedure, especially if a large number of electrodes is used.

#The embodiments of the present invention that are described herein address these problems by providing a medical apparatus comprising a probe, a display screen, a position-tracking system, and a processor. The probe, which comprises one or more electrodes, is inserted into a body of a patient so that it contacts tissue within the body. While the probe and its electrodes are held stationary on the tissue over a preset length of time, the position-tracking system acquires the position coordinates of the electrodes, and the processor acquires EP signals from the electrodes. The processor extracts the respective EP parameters from the signals, and computes a measure of consistency of the values at each electrode location. The processor renders to the display screen a three-dimensional (3D) map of the tissue while superimposing on the map a visual indication of the extracted EP parameters at the locations for which the measure of consistency satisfied a predefined consistency criterion. The processor automatically discards from the map the EP parameters for which the respective measure of consistency did not satisfy the predefined criterion.