A racing heart might be a sign of love or fear ...
Using a mathematical model of the electrocardiogram produced by a human heart, we speed up the heart to produce some interesting music.
Synthetic ECG generator: ECGSYN
McSharry PE, Clifford GD, Tarassenko L, Smith L. (2003). A dynamical model for generating synthetic electrocardiogram signals. IEEE Transactions on Biomedical Engineering 50(3): 289-294; March 2003.