1. A process for pre-processing a digitised acoustic heart sound signal of a patient comprising the steps of identifying or predicting locations of individual heart beats within the heart sound signal; predicting locations and durations for systole and diastole segments of the heart sound signal; compiling a peak array containing peak locations within the heart sound signal that correspond to possible locations of S 1 and S 2 heart sound pulses in the heart sound signal; calculating interval sizes between the peak locations in the peak array; selecting and isolating heart beats in the heart sound signal that were detected with the highest level of confidence based on the predicted durations of the systole and diastole segments of the heart sound signal and the peak array; determining if segmentation of the heart sound signal is possible based on the selected and isolated heart beats; dividing inter-peak intervals that make up the heart sound signal into even and odd groups in the order in which they appear if segmentation of the heart sound signal was found to be possible; and calculating a variance and mean for both of the even and odd groups and taking the group with the largest ratio of variance over mean as corresponding to the diastole intervals and the other group as corresponding to the systole intervals.