This description provides a system and a method for recognizing and monitoring a patient's life-threatening conditions due to pathological electrolyte fluctuations in blood serum and episodes of arrhythmias. The system comprises a patient-worn device with integrated biosignal sensors； real-time signal processing modules integrated in the worn device； and a sudden-death-risk-assessment module that is used in the server, personal computer, or smart device. Life-threatening arrhythmias are recognized by real-time analysis of the continuously recorded photoplethysmogram signal, and electrolyte fluctuations are monitored by analysis of a short electrocardiogram signal recorded by integrated biopotential sensors. The system user shall have the possibility to enter, by means of a smart device, other information related to his or her medical condition that is visible on the physician's smart device. In his smart device, the doctor sees detailed information about the patient's state of health and the risk of life-threatening conditions.The system is designed to monitor the health of patients with chronic kidney disease, who are subject to hemodialysis, but it can also be used to home-monitor other patients after serious illness. The test means are non-invasive, reusable on a continuous basis, do not restrict patient movements, and wireless； test results and feedback are transmitted over the internet.
