A Holter-24h recorder is a device that allows to acquire for an extended period of time (max 24 hours) the biosignal that represents the electrical cardiac activity (ECG), by several electrodes positioned on the thorax skin of the experimental subject. The available devices (H12+, Mortara Instrument Inc., Milwaukee, WI) have the following characterisics:

• Sampling frequency 1000 Hz
• 12 leads
• A/D conversion: 20 bits
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