An ECG controller for an ECG device is connectable to a base ECG lead system (e.g., a 12-lead system) whereby the ECG controller implements an ECG waveform morphology based and ECG lead redundancy based detection and classification of any cable interchange (e.g., a limb cable interchange or a precordial cable interchange) between the ECG controller and the base ECG lead system. Alternatively, the ECG controller is further connectable to a sub-base ECG lead system (e.g., a limb only-lead system or a limited precordial-lead system) whereby the ECG controller implements an ECG waveform morphology based detection and classification of any cable interchange (e.g., a limb cable interchange or a precordial cable interchange) between the electrode interface and the sub-base ECG lead system.

Systems and methods for monitoring the condition of electrodes used in biological signal measurement are provided. One method includes applying a first test signal having a first frequency to at least one of a plurality of electrodes and applying a second test signal having a second frequency to at least one of the plurality of electrodes. Both frequencies are below a frequency range associated with the biological signal. The method further includes capturing the biological signal while applying the plurality of test signals and generating an output signal that includes both the measured biological signal and the plurality of test signals. The method further includes retrieving an output amplitude for each of the plurality of test signals from the output signal and calculating an estimated impedance for each of the plurality of electrodes based on the retrieved output amplitudes of the plurality of test signals.

A system and method for a multi-function remote ambulatory cardiac monitoring system. The system includes a housing and a microprocessor disposed within the housing. The microprocessor controls the remote ambulatory cardiac monitoring system. The system also includes an electrode for sensing ECG signals and the electrode being in communication with the microprocessor. An integrated cellular module also is included in the system, and the cellular module is connected to the microprocessor and disposed within the housing. The integrated cellular module transmits ECG signals to a remote center.

A defibrillation circuit comprising a gas discharge tube and a light source arranged to pre-energize the gas discharge tube in order to provide predictable breakdown conditions of the gas discharge tube. The gas discharge tube may be used as an overvoltage protection device for the defibrillation circuit or for certain parts of the defibrillation circuit. An overvoltage protection device for medical devices is also described. The overvoltage protection device comprises a gas discharge tube and a light source arranged to pre-energize the gas discharge tube in order to provide predictable breakdown conditions of the gas discharge tube.

Devices, systems, and methods are disclosed that identify a type of cable coupled to a receptacle of a defibrillator and that activate one or both of an ECG monitoring module and an energy storage circuit based at least in part on the identified cable type. The cable-type identification may allow a defibrillator to, for example, operate in either or both of an ECG monitoring mode and/or a therapy mode, based on the type of cable that is coupled to the defibrillator. The disclosed devices, systems, and methods can monitor an ECG of a patient and deliver defibrillation therapy to the patient, depending on the type of cable coupled to the defibrillator and/or the type of detected ECG signal of the patient.

A system including a plurality of wireless sensors for monitoring one or more parameters of a subject is provided. The wireless sensors can be attachable to or implantable in the subject and form a network. The sensors can include a sensing component configured to detect a signal corresponding to at least one condition of the subject. The sensors further can include a communication component configured to wirelessly transmit the detected signal to at least another of the plurality of wireless sensors, and wirelessly receive a signal transmitted from at least one of the remaining sensors in the network.

A device and method that detects a lead failure condition for a lead having at least one electrode in contact with body tissue, wherein the lead is connected to the device. The device includes a first filter that filters an electric signal sensed by the at least one electrode to a first filtered signal, and a lead failure detection unit that detects signal characteristics of the first filtered signal. The lead failure detection unit indicates a lead failure condition when the detected signal characteristics correspond to a step response of the first filter.

A long term physiological signal sensing patch, including a water protective film, an electrode layer, a conductive hydrogel layer, a block layer and a first attaching layer. The water protective film provides functions of electrical insulation, stickiness and water protection. The electrode layer includes at least two electrodes attached to the bottom of the water protective film. The conductive hydrogel layer configured beneath the electrodes is electrically conductive and sticky. The block layer is under the electrodes to block water, and accommodates the conductive hydrogel layer. The first attaching layer is provided around the block layer. Therefore, the sensing patch can be attached to the human body for a long period of time to sense physiological signal, which is further transmitted to the external apparatus for more detailed analysis, calculation or display.

Electrode impedances on a body of a subject are measured by connecting a sense electrode, a reference electrode and a return electrode to the body, using the sense electrode to deliver a test current from a current source to the body of the subject, and measuring the potential difference between the sense electrode and the reference electrode. The impedance of the sense electrode on the body is measured in accordance with the measurement of the potential difference between the sense electrode and the reference electrode.

An instrument that utilizes body contact electrodes evaluates the quality of the connections made between the electrodes and the body. An electrode contact quality evaluation circuit performs the quality evaluation, such as by determining contact impedances for the electrodes. The corresponding contact quality of each electrode is conveyed to the user.