Abstract: The present invention relates to a catheter and method for detecting electrical activity in an organ. The catheter comprises: a proximal end with connection means for connecting to a signal processing system and a distal end for being inserted into a patient's organ, at least 3 arms extending from the distal end, each arm comprising at least one electrode. The catheter further comprises a central electrode at the distal end of the catheter. The method comprises: inserting a multi-electrode catheter into a patient's organ; obtaining and conditioning a positioning signal for positioning the electrodes; obtaining causal information about the current location; processing and summarizing the causal information obtained together with causal information about previous locations; visually presenting a recurrence plot of all the causal information obtained; and then moving the catheter to a new location and repeating the method until obtaining a complete recurrence plot.