A system provides cardiac arrhythmia detection and performs blood pressure analysis of multiple catheter channels of blood pressure signals to characterize heart hemodynamic activity. A system for heart performance characterization and abnormality detection includes a repository, data processor and output processor. The repository of data comprises, first distribution data representing a probability distribution of a first patient parameter over a first time period and acquired on a first occasion and second distribution data representing a probability distribution of the first patient parameter over a second time period and acquired on a second occasion subsequent to the first occasion. The data processor calculates an overlap indicator indicating degree of overlap of the first distribution data and the second distribution data in a predetermined interval of the distributions. The output processor provides the calculated overlap indicator to a destination device.