Table 1.

Definitions of the eight classes

Class	Definition
Asystole	A gap of at least 4 s between two successive R-waves
Extreme bradycardia	A heart rate lower than 40 beats per minute for four consecutive beats
Extreme tachycardia	A heart rate higher than 140 beats per minute for 17 consecutive beats
Ventricular fibrillation	An oscillatory ECG waveform of at least 4 s
Ventricular tachycardia	Five consecutive VT beats with heart rate of at least 100 beats per minute
Normal sinus rhythm	A heart rate between 60 and 100 beats per minute for 15 s
Sinus tachycardia	A heart rate between 100 and 140 beats per minute for 17 consecutive beats
Noise/artefacts	All physiological signals are filled with noise or artefacts