Acquisition of long-term cardiac signals for chronodiagnostic utility

Periodical and long-term examination of the cardiac function is important for detecting early-stage disorders, and contributing to chronodiagnosis and chronotherapeutics. Frequent or daily examination utilizing the present test procedures, however, places the patient under stress even when it is administered at home and not during a hospital visit. In order to cope with this issue, monitoring systems whereby a patient is not aware of being examined were developed taking the electrocardiogram (ECG) as an example. The ECG was monitored while the patient was taking a bath or sleeping in bed. The system did not utilize any body surface electrodes but introduced in-water electrodes in the bath and textile electrodes on the bed. These systems made long-term observation feasible without imposing any stress on the patient.