1. A method of detecting changes relating to activity of a heart, the method comprising: embedding time series data relating to the activity of the heart within a reconstructed phase space to generate embedded time series data; partitioning the reconstructed phase space into a plurality of regions; generating a first matrix having a plurality of cells, wherein the first matrix comprises a row and a column for each of the plurality of regions, wherein a value stored in each cell is based on a probability the activity of the heart will transition from a first region associated with the cell to a second region associated with the cell and a rate of separation of trajectories of the embedded time series data within at least one of the first region and the second region, and wherein the first matrix is generated using a first set of the time series data associated with a normal operating condition of the heart; generating a second matrix based on a second set of the time series data; and comparing the first matrix and the second matrix to detect a heart attack; wherein comparing the first matrix and the second matrix comprises: calculating a state change parameter representing a degree of state change between a first state associated with the first matrix and a second state associated with the second matrix; and comparing the state change parameter to a threshold value; and wherein the method further comprises performing an action relating to the heart attack when the state change parameter exceeds the threshold value.