Patent claim: The system according to claim 8 wherein the processor is configured to identify the gaps by detecting the gaps that are larger than a first threshold but smaller than a second threshold.

Related passage: Fig.4 is a flow chart that schematically illustrates a method for assessing intracardiac ablation that is applied at step 72 in accordance with an embodiment of the invention.Processor 40 applies decision logic 80 typically in software based on the date collected during ablation step 64 at a given site and possibly the data collected before andor after the ablation steps 6870.The following filters may be appliedA position stability filter 82 Processor 40 measures changes in the location of catheter 24 during the ablation after compensating for respiratory movementstep 70.Filter 82 typically requires that the variation of the location over a predefined minimum ablation time be no greater than a predefined maximum distance.The variation may be measured for example in terms of a standard deviation about the mean position during the ablation time.A velocity filter 84.This filter can be used to detect loss of stability.For this purpose processor 40 measures the displacement between successive locations of the catheter and implicitly or explicitly divides by the time increment between the locations to find the velocity of motion of the catheter.If the velocity is above a specified threshold such as 10 mmsec the catheter may be considered to be unstable.An impedance drop filter 86.Processor 40 typically takes the impedance value of the first position in a stable site as a base impedance value and then tests subsequent impedance values against a predefined percentage threshold.For example the impedance drop in subsequent measurements may be defined as 1 current position impedance valuebase impedance value100.If this drop is greater than the percentage threshold the site is considered to have been ablated and is therefore marked on map 46.Alternatively or additionally the amount of impedance drop may be taken into account in coloring the corresponding mark 50 52.An ECG drop filter 88.For each stable site processor 40 may calculate for example the maximum peaktopeakECG amplitude value in an ECG data span of two seconds ending at the time at which a corresponding position measurement was made.If the calculated amplitude is less than a predefined threshold the site may be marked as having been ablated andor colored to indicate the amount of ECG drop.A force level filter 90.At each stable site processor 40 tests the average contact force between catheter 24 and the heart tissue against a predefined threshold.When the average contact force is above a predefined threshold the site is marked as having been ablated and may be colored to indicate the average force level.Additionally or alternatively processor 40 may assess the force percentage i.e.the fraction of the time during which the catheter dwelled at a given ablation site for which the force was above a certain force threshold number of postions exceeding the contact force thresholdtotal number of positions in the stable site100.If the percentage value is above a predefined time percentage threshold the site is marked andor the mark may be colored according to the percentage value.