Defibrillators, ImplantableMicroelectrodesImplantable NeurostimulatorsElectrodes, ImplantedTachycardia, VentricularEquipment FailureElectric CountershockVentricular FibrillationProstheses and ImplantsDeath, Sudden, CardiacArrhythmias, CardiacPacemaker, ArtificialInfusion Pumps, ImplantableEquipment DesignAction PotentialsElectrochemical TechniquesAnti-Arrhythmia AgentsEquipment Failure AnalysisElectric InjuriesAmplifiers, ElectronicEquipment SafetyDevice RemovalTelemetryNeural ProsthesesSyncopeElectrophysiologyMicrotechnologyMembrane PotentialsProsthesis ImplantationCardiac Pacing, ArtificialAmiodaroneElectrocardiographyBiosensing TechniquesElectric StimulationPurkinje FibersElectric Power SuppliesElectrophysiologic Techniques, CardiacCardiac Resynchronization Therapy DevicesRadio Frequency Identification DeviceElectrochemistryElectric ImpedanceElectrocardiography, AmbulatoryArtificial OrgansElectrodesHeart Conduction SystemTime FactorsMiniaturizationHeart-Assist DevicesIon-Selective ElectrodesHeart FailureFollow-Up StudiesTreatment OutcomePapillary MusclesMonitoring, AmbulatoryStereotaxic TechniquesElectromagnetic PhenomenaImplants, ExperimentalCardiac Resynchronization TherapyHeart ArrestDeep Brain StimulationPrimary PreventionPotassiumCatheters, IndwellingTachycardiaSotalolDogsVisual ProsthesisNeuronsBiocompatible MaterialsSignal Processing, Computer-AssistedElectronicsRemote Sensing TechnologyNecturus maculosusProsthesis-Related InfectionsElectric ConductivityWireless TechnologyGuinea PigsCatsEndocardiumRetrospective StudiesStroke VolumeProspective StudiesVentricular Dysfunction, LeftTachycardia, SupraventricularElectrophysiological PhenomenaMicro-Electrical-Mechanical SystemsCardiomyopathiesIridiumDeath, SuddenHeart VentriclesBrugada SyndromeRisk AssessmentFeasibility StudiesMonitoring, PhysiologicQuinidineCardiomyopathy, DilatedNeurophysiologyElectric Stimulation TherapyResins, SyntheticConductometry