1. A method of decomposing an electrocardiogram (ECG) signal, the method comprising: receiving an ECG signal; segmenting the received ECG signal into a set of cycle segments; aligning the set of cycle segments; generating a set of cross-sectional signals from the cycle segments; separating, using the signal separation process, the set of cross-sectional signals into a set of statistically substantially independent components; and detecting, using the set of components, an abnormal cardiac signal.