MicroelectrodesDefibrillators, ImplantableElectrodes, ImplantedImplantable NeurostimulatorsIon-Selective ElectrodesTachycardia, VentricularEquipment FailureAction PotentialsProstheses and ImplantsMembrane PotentialsElectric CountershockElectrochemical TechniquesVentricular FibrillationEquipment DesignElectrophysiologyDeath, Sudden, CardiacArrhythmias, CardiacElectrochemistryEquipment Failure AnalysisPacemaker, ArtificialInfusion Pumps, ImplantableElectric StimulationPotassiumAnti-Arrhythmia AgentsMicrotechnologyBiosensing TechniquesPurkinje FibersElectrodesElectric InjuriesAmplifiers, ElectronicEquipment SafetyDevice RemovalTelemetryNeural ProsthesesSyncopeElectric ImpedanceMiniaturizationExtracellular SpaceCardiac Pacing, ArtificialElectrocardiographyNecturus maculosusSodiumProsthesis ImplantationHeart Conduction SystemNeuronsTime FactorsAmiodaronePapillary MusclesHydrogen-Ion ConcentrationGuinea PigsElectric ConductivityChloridesConductometryCatsElectric Power SuppliesFluorocarbon PolymersBicarbonatesStrophanthidinElectrophysiologic Techniques, CardiacCardiac Resynchronization Therapy DevicesIon ExchangeNecturusMicromanipulationRadio Frequency Identification DeviceDogsMicrochip Analytical ProceduresCarbonElectrocardiography, AmbulatoryArtificial OrgansCalciumHeart-Assist DevicesHeart FailureFollow-Up StudiesTreatment OutcomeEvoked PotentialsGlassIon TransportOxygenIontophoresisRabbitsRats, Sprague-DawleyQuinidineMonitoring, AmbulatoryPatch-Clamp TechniquesSiliconStereotaxic TechniquesElectromagnetic PhenomenaImplants, ExperimentalElectrophysiological PhenomenaCardiac Resynchronization TherapyTetrodotoxinElectroplatingHeart ArrestDeep Brain StimulationPrimary PreventionHeartCatheters, IndwellingHeart Ventricles4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic AcidTachycardia